Dissertationen zum Thema „Kiwifruit“

Quantify the magnitude, sources and distribution of variation in fruit quality traits within kiwifruit populations and identify opportunities for the management of this variation. Near-infrared (NIR) grading was used as a tool for monitoring fruit quality, and measurements combined with orchard/vine information to investigate opportunities for the management of the variation in fruit quality traits with a particular focus on fruit DM. NIR enabled non-destructive assessment of the quality characteristics of individual fruit from 96 commercial orchards, comprising 550 fruit-lines, across four consecutive seasons, resulting in a dataset of measurements made on 146.7 million individual fruit. The distribution of quality traits within fruit populations and the relationships between quality traits were examined. The spatial component of variation in fruit quality was investigated to assess the potential for zonal management practices. Finally, the effects of growth temperatures on fruit quality were studied. Significant variation in fruit quality was observed between-seasons, between-orchards, and between-vines within an orchard. From comparison of CVs between quality traits, cropload was more variable than fruit weight which varied more than fruit DM, independent of the production scale considered (between-orchard or between-vine). Across a hierarchy of fruit populations (individual vine, fruit-line and orchard), the majority of fruit quality distributions demonstrated significant deviations from normality. However, departures from normality can be tolerated for estimation of the proportion of fruit with specific quality criteria. The sources of variation in fruit weight and DM populations were investigated at both a between-orchard scale and a within-orchard scale. Between-orchard variation was significant, however, the majority of variation occurred within-fruitlines, within-orchards and within seasons. The within-fruitline component of variation was investigated separately. Both between-vine and within-vine variation were significant, but within-vine variation was dominant. The focus of management should be on reducing variation occurring within-fruitlines within-orchards, which is largely attributable to variation occurring within the individual vine. Higher croploads per vine have negative consequences for fruit weight but variable effects on DM. Increasing croploads reduce both FW and DW allocations for each fruit, therefore the effect of cropload on DM is dependent on the relative reductions in FW and DW. The DW allocations to fruit are not limited by DW production, at least up to the croploads observed in this study (≤65 fruit m-2). The potential for zonal management was investigated. Variation in fruit quality characteristics between-orchards across the Te Puke growing region, and between-vines within an individual orchard area were investigated using geostatistics. A spatial component to variation was identified both between-orchard and between-vine. However, the effect of spatial variation was diluted by that of non-spatial variation and therefore, zonation between orchards or between areas within-orchards should not be where the effort in managing variation is concentrated. Orchard altitude correlated with some aspects of fruit quality. Mean fruit weight declined 0.5g and within-orchard variation in fruit weight declined 0.25 units with a 25m increase in orchard altitude. Mean fruit DM was independent of orchard altitude and within-orchard variability in DM declined 0.023 units per 25m increase in orchard altitude. Differences in orchard altitude equated with differences in growth temperatures. Warm spring and cool summer temperatures favour the growth of high DM fruit. The effects of spring temperatures on canopy development and maturation were investigated to elucidate potential physiological mechanisms for temperatures effects on fruit growth. Higher spring growth temperatures increased the rate of total leaf area development and promoted development of leaf photosynthesis. Higher spring growth temperatures favoured a more positive carbon balance, which has beneficial effects on the development of fruit quality characteristics. Post-harvest, the traditional practice of grading fruit into count sizes generally also segregates for DM, and large count size fruit will often have higher DM than small sized fruit. Between fruit populations, a positive correlation was identified between fruit DM and acidity; therefore, segregation of the inventory by DM will also segregate for acidity. High DM fruit are also more acidic with a higher, more favourable brix/acid ratio when ripe. It is recommended that fruit DM status be managed in the inventory, not by maturity area as is the current practice, but by groups of similar count sizes within maturity areas.

A system has been developed to aid in the establishment of Agrobacterium-mediated transformation for new plant species. A series of binary vectors have been constructed that express a chimaeric β-D-glucuronidase (GUS) gene in plants cells but not in bacterial cells. This feature allows GUS activity from transformed plant cells to be assayed in the presence of Agrobacterium. Preliminary experiments examined the expression of these chimaeric GUS genes in transformed petunia leaf discs. GUS expression was detectable 2 days after inoculation, peaked at 3 – 4 days and then declined; if selection was imposed expression increased again after 10 - 14 days. The amount of expression observed 4 days after inoculation correlated well with stable integration as measured by kanamycin resistance, hormone independence, and gall formation. Histochemical staining of inoculated leaf discs confirmed the transient peak of GUS expression 3 - 4 days after inoculation. Surprisingly, GUS expression was concentrated in localized zones on the circumference of the disc; within these zones essentially all the cells appeared to be expressing GUS. These results suggest that the frequency of gene transfer from Agrobacterium is extremely high within localized regions of the petunia leaf explants, but that the frequency of stable integration is several orders of magnitude lower. A reliable Agrobacterium-mediated transformation system has been established for kiwifruit (Actinidia deliciosa var. deliciosa cv. Hayward) by using transient expression of GUS to monitor gene transfer frequencies. In vitro culture of kiwifruit plants and conditions for regeneration of plants from leaf discs have been established. Several factors were found to improve gene transfer frequencies in kiwifruit: (i) healthy actively growing source tissue; (ii) the use of Agrobacterium strain A281; (iii) the presence of a layer of moistened filter paper between the leaf explants and the cocultivation media; and (iv) the presence of 20 μM acetosyringone in both the bacterial culture media and in the cocultivation media. Pre-culture of leaf explants significantly inhibited gene transfer, particularly at the cut edge of the explants. Using the optimized transformation system, at least one transgenic plant can be regenerated from each leaf inoculated. Stable transformation frequencies have been shown to vary significantly between different binary vectors. Phenotypic, PCR, and Southern analysis has confirmed the presence of stably integrated T-DNA in several transgenic kiwifruit plants.

The activity of superoxide dismutase (SOD) was determined in three kiwifruit (Actinidia) species including A. deliciosa, A. chinensis, and A. arguta. Among the species tested, the highest SOD activity was found in crude extracts prepared from fruit tissues of A. deliciosa. The highest enzyme activity was localized in seed, followed by locules, core and outer pericarp (OP). SOD activity in crude extract of whole fruit remained stable for at least one month when stored at -20℃. The effect of synthetic protease inhibitors (PI) on SOD activity was investigated. Supplementing crude kiwifruit extracts with PI improved SOD activity in freshly prepared extracts, and in extracts stored at 4℃, but had no effect on those stored at -20℃. Among the PI used, iodoacetamide (an inhibitor of cysteine proteases, for example, actinidin which is a principal protease found in kiwifruit) and PMSF (an inhibitor of serine proteases), had the most and least influence on SOD activity in crude kiwifruit extracts, respectively. There was a significant increase in SOD activity in kiwifruit (that were relatively firm) when the fruits were stored at low temperature (4℃). An increase in SOD activity was also correlated with a decrease in fruit firmness. Staining fruit tissues with nitroblue tetrazolium (NBT) provided evidence for stress-induced superoxide generation in kiwifruit tissues. Taken together, the changes in SOD activity and the capacity for stress-inducible superoxide production in post-harvest kiwifruit suggest that SOD might play a fundamental role in the storage life/ripening of kiwifruit.

El consum habitual de fruita (com el kiwi) en la dieta té un efecte molt beneficiós per a la salut. No només és una excel·lent font de vitamines, fibra i minerals, sinó que a més posseeix compostos fitoquímics que contribueixen a la salut. D'altra banda, cada dia més els consumidors demanen d'aliments de preparació ràpida, amb una alta qualitat nutritiva, sensorial i el mínim d'additius per a la seva conservació. RESUM La primera impressió que els consumidors reben de les fruites és l'aparença o aspecte extern, sent la més important per a la seva acceptació i decisió de compra. La forma i mida és un dels aspectes més fàcilment discernibles, tot i que generalment no és un caràcter de qualitat decisiu. Només en cas de malformacions o defectes morfològics podria ser-ho. Durant i després de la collita del kiwi, un cert percentatge de la collita no pot ser destinat a la seva distribució ja que no arriba als estàndards de comercialització. D'altra banda, hi ha un sector de població que necessita de facilitats a l'hora d'incentivar el consum de fruites, i en concret de kiwis, com són els nens, els ancians i certs sectors per las quals, per motius de treball o pràctics, és un inconvenient el rentar, pelar i tallar certes fruites fora de casa. En base a aquest plantejament, a la present Tesi ens hem proposat estudiar l'aplicació d'una tecnologia no tèrmica, com són les Altes Pressions Hidrostàtiques (HHP) per a l'obtenció d'un puré de kiwi segur, saludable (amb les seves propietats nutritives) i desitjable (sense perdre propietats organolèptiques). En la primera fase d'aquesta Tesi es van determinar les condicions de pressió, temperatura i temps del tractament HHP per reduir la seva càrrega microbiana endògena i estudiar l'evolució dels supervivents. A més es van inocular diferents indicadors de patògens, obtenint letalitats i capacitat de recuperació dels supervivents. A més a més, es van monitoritzar paràmetres que poguessin influir en la supervivència o creixement dels microorganismes, com pH, sòlids solubles, temperatures. En una segona fase, es van estudiar els paràmetres de qualitat fisicoquímica (color instrumental, degradació de les clorofil·les, reologia), nutritius (Vitamina C) i sensorials (panell de tastadors), en aquelles condicions que prèviament havien demostrat una seguretat microbiològica inicialment i al llarg del seu emmagatzematge. A mena de resum, destaquem els següents resultats obtinguts, respecte a la inactivació d'aerobis mesòfils (AM) totals es van observar reduccions de 2 i 3 Log a 300 MPa / 0.1 min i resta de condicions, respectivament. Els supervivents en els AM van ser esporulats (SP), ja que van coincidir amb els recomptes de supervivents. Però en cap cas hi va haver proliferació durant el seu emmagatzematge a 30 dies. Els microorganismes patògens inoculats (S. aureus i E. coli), van resultar ser molt més sensibles, ja que a partir de 500 MPa a qualsevol temps i temperatura assajades, no es observar supervivents, amb reduccions de 5 i 7 Log, respectivament. Les menors diferències de color entre les mostres pressuritzades enfront del control (ΔE) van ser les tractades a 10 °C, 5 minuts i 300 < 700 < 500 MPa. A més a més, el contingut de clorofil·les a i b, amb els tractaments de HHP assajats es va mantenir de l'ordre del 50-70% per a clorofil·la a i 60-80% per a clorofil·la b. Amb el tractament tèrmic de pasteurització aplicat només va quedat al 0 i 10% de clorofil·la a i b, respectivament. Per contra, la formació de feofitines (a i b) en les mostres tractades per HHP gairebé no va variar respecte al control, mentre que les mostres pasteuritzades van doblar el seu contingut. Es va poder observar que el contingut total de Vitamina C en les mostres tractades per HHP, tot just es va reduir respecte al seu control, durant el seu emmagatzematge. Només al dia 60, la diferència respecte al seu control va oscil·lar entre un 50-70% menor. A nivell d'anàlisi sensorial, els panelistes van distingir clarament les mostres tractades tèrmicament de les pressuritzades i control. Cal destacar que dels tractaments assajats, les mostres de 300 i 500 MPa a 15 min, van ser les que els panelistes van col·locar més pròximes al control Amb els resultats obtinguts en el present treball es demostra que els tractaments per HHP, són una alternativa per augmentar la vida útil del puré de kiwi, mantenint la seguretat microbiològica i unes característiques reològiques, organolèptiques i nutritives satisfactòries per als consumidors, com a mínim fins al dia 30 de conservació en refrigeració.
El consumo habitual de fruta (como el kiwi) en la dieta tiene un efecto muy beneficioso para la salud. No sólo es una excelente fuente de vitaminas, fibra y minerales, sino que además posee compuestos fitoquímicos que contribuyen a la salud. Por otro lado, los consumidores demandan cada día más de alimentos de preparación rápida, con una alta calidad nutritiva, sensorial y el mínimo de aditivos para su conservación. RESUMEN La primera impresión que los consumidores reciben de las frutas es la apariencia o aspecto externo, siendo la más importante para su aceptación y decisión de compra. La forma y tamaño son unos de los aspectos más fácilmente discernibles, aunque generalmente no es un carácter de calidad decisivo. Solo en caso de malformaciones o defectos morfológicos podría serlo. Durante y después de la cosecha del kiwi, un cierto porcentaje de la recolección no puede ser destinado a su distribución ya que no alcanza los estándares de comercialización. Por otro lado, existe un sector de población que precisa de facilidades a la hora de incentivar el consumo de frutas, y en concreto de kiwis, como son los niños, los ancianos y ciertos sectores para los cuales, por motivos de trabajo o prácticos, resulta un inconveniente el lavar, pelar y cortar ciertas frutas fuera de casa. En base a este planteamiento, en la presente Tesis nos hemos propuesto estudiar la aplicación de una tecnología no térmica, como son las Altas Presiones Hidrostáticas (HHP) para la obtención de un puré de kiwi seguro, saludable (con sus propiedades nutritivas) y apetecible (sin perder propiedades organolépticas). En la primera fase de esta Tesis se determinaron las condiciones de presión, temperatura y tiempos del tratamiento HHP para reducir su carga microbiana endógena y estudiar la evolución de los supervivientes. Además se inocularon diferentes indicadores de patógenos, obteniéndose sus letalidades y capacidad de recuperación de los supervivientes. A su vez, se monitorizaron parámetros que pudieran influenciar en la supervivencia o crecimiento de los microorganismos, como pH, sólidos solubles, temperaturas. En una segunda fase, se estudiaron los parámetros de calidad fisicoquímica (color instrumental, degradación de las clorofilas, reología), nutricional (vitamina C) y sensoriales (panel de catadores), en aquellas condiciones que previamente habían demostrado una seguridad microbiológica inicialmente y a lo largo de su almacenamiento. A modo de resumen, destacamos los siguientes resultados obtenidos, respecto a la inactivación de aerobios mesófilos (AM) totales se observaron reducciones de 2 y 3 Log a 300 MPa/0.1 min y resto de condiciones, respectivamente. Los supervivientes en los AM fueron esporulados (SP), ya que coinciden con los recuentos de supervivientes. Pero en ningún caso hubo proliferación durante su almacenamiento a 30 días. Los microorganismos patógenos inoculados (S. aureus y E. coli), resultaron ser mucho más sensibles, ya que a partir de 500 MPa a cualquier tiempo y temperatura ensayadas, no se observaros supervivientes, con reducciones de 5 y 7 Log, respectivamente. Las menores diferencias de color entre las muestras presurizadas frente al control (ΔE) fueron las tratadas a 10 °C, 5 min y 300 < 700 < 500 MPa. A su vez, el contenido de clorofilas a y b, con los tratamientos de HHP ensayados se mantuvo del orden del 50-70% para clorofila a y del 60-80% para clorofila b. Con el tratamiento térmico de pasteurización aplicado solamente quedó 0 y 10% de clorofila a y b, respectivamente. Por el contrario, la formación de feofitinas (a y b) en las muestras tratadas por HHP apenas varió respecto al control, mientras que las muestras pasteurizadas doblaron su contenido. Se pudo observar que el contenido total de Vitamina C en las muestras tratadas por HHP, apenas se redujo respecto a su control, durante su almacenamiento. Sólo al día 60, la diferencia con respecto a su control osciló entre un 50-70% menor. A nivel de análisis sensorial, los panelistas distinguieron claramente las muestras tratadas térmicamente de las presurizadas y control. Cabe resaltar que de los tratamientos ensayados, las muestras de 300 y 500 MPa a 15 min, fueron las que los panelistas colocaron más cercanas al control. Con los resultados obtenidos en el presente trabajo se demuestra que los tratamientos por HHP, son una alternativa para aumentar la vida útil del puré de kiwi, manteniendo la seguridad microbiológica y unas características reológicas, organolépticas y nutricionales satisfactorias para los consumidores, como mínimo hasta el día 30 de conservación en refrigeración.
Regular consumption of fruit (including kiwi) in the diet has a beneficial effect on health. It is not only an excellent source of vitamins, fiber and minerals, it also has phytochemicals that contribute to health. On the other hand, more and more consumers demand for fast food with high nutritional quality, sensory and minimum of additives for conservation. ABSTRACT The first impression consumers have from fruit it is the appearance or external aspect, being the most important for acceptance and purchase decision. The shape and size are among the most easily discernible aspects, but generally it is not a decisive quality character. Only if morphological abnormalities or defects could be a cause of reject. During and after kiwi harvest, a certain percentage of the harvest cannot be intended for distribution on not reaching marketing standards. On the other hand, there is a sector of the population that requires encourage for fruits consumption, specifically kiwis, such as children, the elderly and certain sectors whom for work or practical reasons, is a drawback to wash, peel and cut some fruits. Based on this approach, in this Thesis we intend to study the application of a non-thermal technology, such as high hydrostatic pressure (HHP), to obtain a kiwi puree safe, healthy (with its nutritional properties) and desirable (without losing organoleptic properties). In the first phase of this thesis the conditions of pressure, temperature and time of HHP treatment to reduce their endogenous microbial load and to study the evolution of the survivors were determined. Also, different indicators of pathogens were inoculated, obtaining their lethality rates and the resilience of the survivors. In turn, parameters that might influence the survival or growth of microorganisms such as pH, soluble solids, and temperature were monitored. In a second stage, physicochemical quality parameters (instrumental color, degradation of chlorophylls, rheology), nutritional (vitamin C) and sensory (taste panel), in the conditions that had previously shown a microbiological safety at the beginning and during storage, were studied. To summarize, we highlight the following results with respect to inactivation of aerobic mesophilic (AM) Total reductions Log 2 and 3 were observed at 300 MPa / 0.1 min and other conditions, respectively. The survivors were sporulated AM (SP), as they match survivors counts. In no case there was growth during storage at 30 days. For inoculated pathogenic microorganisms (S. aureus and E. coli), proved to be much more sensitive as from 500 MPa at any time and temperature tested, no survivors watch yourself, with reductions of 5 and 7 Log, respectively The lesser differences in color between pressurized samples versus control (ΔE) were treated at 10 °C, 5 min and 300 <700 <500 MPa. In turn, the content of pigment molecules with HHP treatments tested (300, 500 and 600 MPa and 0.1, 5 and 15 min) was maintained in the range 50-70% for chlorophyll a and 60-80% for chlorophyll b. With the pasteurization heat treatment remained just 0 and 10% for chlorophyll a and b, respectively. Conversely pheohytins formation in samples treated by HHP, hardly changed relative to the control, pasteurized samples doubled its contents. It was observed that the total content of Vitamin C in the samples treated by HHP, the gap narrowed just about control during storage, only at day 60 compared to control ranged between 50-70% lower. A level sensory testing, panelists clearly distinguished the samples heat treated and the pressurized control. It should be noted that the treatments tested, samples of 300 and 500 MPa for 15 min, were placed the closest to the control by panelists. With the results of this study demonstrated that treatment by HHP, are an alternative to increase the life of mashed kiwi, maintaining the microbiological safety and rheological, organoleptic and favorable to consumers nutritional characteristics, at least until the 30th day of storage.

The chlorophyll degradation pathway is central to a number of plant processes including senescence and fruit ripening. However, the regulation of the chlorophyll degradation pathway enzymes is not well understood. The aim of this thesis was to elucidate the genetic mechanisms that control changes in pigment composition leading to fruit flesh yellowing in kiwifruit. Actinidia deliciosa and A. chinensis fruit, which are green and yellow, respectively, provide an opportunity to study the regulation of chlorophyll levels. The expression of genes that code for enzymes of the chlorophyll and cytokinin metabolic pathways was measured using qRT-PCR. Candidates for chlorophyll degradation regulatory points were then characterised for functionality by transient transformation in N. benthamiana. The endogenous cytokinin levels were measured in kiwifruit and transient activation assays were carried out with the promoters of key candidate genes. Overall, expression of the chlorophyll degradation genes was elevated in yellow fruit and expression of biosynthetic genes was higher in green fruit. The chlorophyll degradation-associated protein, STAY-GREEN2 (SGR2), was more highly expressed in yellow fruit, and transient over-expression of SGR was sufficient to drive chlorophyll degradation. Expression of isopentenyl transferase (IPT), the rate-limiting step for cytokinin biosynthesis, showed an increase towards maturity in green fruit, but not in yellow fruit. However, both fruit had similar high levels of cytokinin nucleotides and free bases. A gene coding for O-glucosylation was also highly expressed in green fruit. Green fruit contained higher levels of cytokinin O-glucosides and ribosides towards maturity, suggesting differences in cytokinin signalling, which could lead to regulation of chlorophyll levels via activation of the SGR promoter by transcription factors. It is likely that the chlorophyll degradation pathway and cytokinin metabolism are linked. The differential expression of cytokinin response regulators could lead to differential regulation of cytokinin levels in the fruit of the two species, and possibly differential regulation of the chlorophyll degradation pathway. Progress towards elucidation of the control of chlorophyll levels provides knowledge of this key process in kiwifruit and potentially gene-based markers for breeding new kiwifruit cultivars.

Research in this thesis describes the characterisation of mRNA sequences coding for actinidin, a cysteine protease found in abundance in the fruit of kiwifruit (Actinidia deliciosa). The first step in the characterisation required the isolation of mRNA from ripe kiwifruit tissue. The suitability of a number of RNA extraction procedures was investigated. The method finally adopted differed from that used for unripe fruit tissue, and was chosen as a result of the nature of the polysaccharide that contaminated nucleic acids prepared from extracts of kiwifruit fruit tissue. RNA extracted from ripe fruit was used to synthesis a partial cDNA library and clones for actinidin were isolated. A number of these cDNA clones were sequenced; three clones were almost full-length. The actinidin cDNA clones obtained fall into two broad sequence classes. The majority of them encode acidic proteins (pI˜4.7), with 97% homology to the published amino acid sequence of actinidin. The second class encode basic proteins (pI˜8.1), with 83% homology to the published amino acid sequence of actinidin. Both classes of actinidin cDNA sequence encode zymogens, which contain N- and C-terminal extensions not present in the mature form of the enzyme. The N-terminal extension of both sequence classes includes a putative signal peptide. Northern hybridization analysis was used to investigate the tissue specificity of actinidin mRNA expression, and the expression of mRNA for the two actinidin sequence classes during fruit ripening. Both actinidin sequence classes were expressed differentially during the latter stages of kiwifruit fruit development and through post-harvest fruit ripening. The expression of both sequence classes increased from just prior to fruit maturity through ripening and reached a maximum as fruit attained the stage of 'eating' ripeness. The level of expression of the sequences encoding acidic actinidin reached a plateau at this point, while the expression of the sequence encoding basic actinidin appeared to decrease slightly as fruit continued to ripen. The sequences encoding acidic actinidin were expressed during ripening at a much higher level than those encoding basic actinidin. No actinidin mRNA was detected in other tissues except for very low levels of the acidic form in kiwifruit leaf, and low levels of the basic form in senescing petals. A full-length, acidic, actinidin cDNA sequence was introduced into tobacco (Nicotiana tabacum) plants via Agrobacterium tumefaciens-mediated transformation. Using the binary vector pGA643, the sequence was introduced in both the sense and antisense orientation relative to the cauliflower mosaic virus 35S promoter and transgenic plants were obtained for both sequence orientations. The presence of the T-DNA cassette (containing the actinidin sequence) in the plant genomes was determined using PCR analysis, and confirmed by Southern hybridization. A number of the transgenic plants contained multiple insertions of the actinidin sequence, and most plants contained at least one intact copy of the T-DNA cassette. The transcription of the introduced actinidin sequence was investigated by Northern hybridization analysis. All of the plants containing actinidin in the sense orientation, and some of those incorporating the antisense construct, transcribed the actinidin sequence. Attempts to detect actinidin protein in the transgenic plants were unsuccessful. Acidic actinidin was identified as one of the most abundant bands in the total protein profile from ripe kiwifruit fruit tissue. The identity of the protein was confirmed by N-terminal sequence analysis. The electrophoretic mobility of actinidin, both in the total cell homogenate and when partially purified, suggested that the first step in post-translational processing of the zymogen may be the removal of the N-terminal extension. Actinidin was also partially purified and used to raise antibodies. Poor specificity of the antibody for actinidin led to preliminary evidence for the glycosylation of actinidin.

A new formulate containing citokinins, that is commercialized as Cytokin, has been introduced as dormancy breaking agents. During a three-years study, Cytokin was applied at different concentrations and application times in two producing areas of the Emilia-Romagna region to verify its efficacy as a DBA. Cytokin application increased the bud break and showed a lateral flower thinning effect. Moreover, treated vines showed an earlier and more uniform flowering as compared to control ones. Results obtained on the productive performance revealed a constant positive effect in the fruit fresh weight at harvest. Moreover, Cytokin did not cause any phytotoxicity even at the highest concentrations. Starting from the field observation, which suggested the involvement of cytokinins in kiwifruit bud release from dormancy, 6-BA was applied in open field condition and molecular and histological analyses were carried out in kiwifruit buds collected starting from the endo dormant period up to complete bud break to compare the natural occurring situation to the one induced by exogenous cytokinin application. In details, molecular analyses were set up on to verify the expression of genes involved in the reactivation of cell cycle: cyclin D3, histone H4, cyclin-dependent kinase B, as well as of others which are known to be up regulated during bud release in other species, i.e.isopenteniltransferases (IPTs), which catalyze the first step in the CK biosynthesis, and sucrose synthase 1 and A, which are involved in the sugar supplied. Moreover, histological analyses of the cell division rate in kiwifruit bud apical meristems were performed. These analyses showed a reactivation of the cell divisions during bud release and changes in the expression level of the investigated genes.

A new formulate containing citokinins, that is commercialized as Cytokin, has been introduced as dormancy breaking agents. During a three-years study, Cytokin was applied at different concentrations and application times in two producing areas of the Emilia-Romagna region to verify its efficacy as a DBA. Cytokin application increased the bud break and showed a lateral flower thinning effect. Moreover, treated vines showed an earlier and more uniform flowering as compared to control ones. Results obtained on the productive performance revealed a constant positive effect in the fruit fresh weight at harvest. Moreover, Cytokin did not cause any phytotoxicity even at the highest concentrations. Starting from the field observation, which suggested the involvement of cytokinins in kiwifruit bud release from dormancy, 6-BA was applied in open field condition and molecular and histological analyses were carried out in kiwifruit buds collected starting from the endo dormant period up to complete bud break to compare the natural occurring situation to the one induced by exogenous cytokinin application. In details, molecular analyses were set up on to verify the expression of genes involved in the reactivation of cell cycle: cyclin D3, histone H4, cyclin-dependent kinase B, as well as of others which are known to be up regulated during bud release in other species, i.e.isopenteniltransferases (IPTs), which catalyze the first step in the CK biosynthesis, and sucrose synthase 1 and A, which are involved in the sugar supplied. Moreover, histological analyses of the cell division rate in kiwifruit bud apical meristems were performed. These analyses showed a reactivation of the cell divisions during bud release and changes in the expression level of the investigated genes.

The importance of European honey bees in improving fruit set, yield and fruit weight of kiwifruit on the central east coast of Australia was investigated. Field investigations were carried out using different bee saturations and different types of male pollen parents. These investigations confirmed the importance of honey bees in kiwifruit fruit set, yield and fruit weight. However, the results suggested that increasing bee activity alone may not increase pollination of kiwifruit by honey bees. Many factors need to be understood before introducing bees into the orchard. Bees were more effective during the early part of the flowering period, and bee activity varied according to the sex of the vine, planting design and the time of day. The type of male pollen parents also influenced fruit size and quality. Flowers pollinated by different pollen parents were assessed for pollen tube growth and histochemical changes. The resulting fruit were also examined for weight and seed numbers. Honey bees play the major role in the size and yield of kiwifruit, but the design of male vines, their age and type of male pollen may also contribute. The kiwifruit pistil also possesses important features that can be considered as adaptations to insect pollination.

Botrytis cinerea and Sclerotinia sclerotiorum are the two most serious pathogens on kiwifruit in New Zealand. Because of the pesticide regulations in some of the countries to which New Zealand exports fruit, total protection from Botrytis stem end rot with current dicarboximide fungicides is not possible. The aim of this thesis was to investigate biological control measures for Botrytis stem end rot and Sclerotinia diseases of kiwifruit. More than 1000 microorganisms, isolated from the leaves and flowers of kiwifruit during spring and autumn, and selected from BCAs reported to be effective against B. cinerea and./or S. sclerotiorum, were tested in vitro for their antagonistic ability against B. cinerea and S. sclerotiorum. Successful antagonists were those that, in dual culture on agar plates, produced a zone of inhibition, an area of browning of the pathogens, or grew rapidly over the pathogens and inhibited their growth. The fifty most promising isolates from the initial screen were tested on fruit for their ability to reduce Botrytis and Sclerotinia fruit rots. Mature kiwifruit were artificallv wounded and dual inoculated with a spore suspension of one of the fifty test organisms and either a conidial suspension of B. cinerea or a mycelial suspension of S. sclerotiorum. Following 8-12 weeks incubation in a cool store, fruit were assessed for Botrytis or Sclerotinia induced rot. Isolates of Bacillus spp., Epicoccum purpurascens, Pseudomonas sp. and Trichoderma. spp. reduced, Botrytis fruit rot from 92% (inoculated control) to 0%.Isolates of Alternaria spp., pestalotia sp. and a non-sporulating isolate also reduced the number of fruit rotting to some extent. Similarly, isolates of Bacillus spp., E purpurascens and Trichoderma spp. reduce d Sclerotinia fruit rot from 100% (inoculated control) to 0%. Isolates of Alternaria spp., Myrothecium verrucaria and Pestalotia sp. were also successful at reducing the level of Sclerotinia fruit rot. It was considered undesirable if potential biological control agents (BCAs) were able to colonize kiwifruit that were to be marketed for human consumption. In order to determine if microorganisms, shown to be effective in preventing Botrytis or Sclerotinia fruit rot, were capable of themselves colonizing fruit, isolations were made from fruit dual inoculated with B. cinerea, S. sclerotiorum and/or one of several BCAs. Strains of the BCAs Bacillus spp., Pseudomonas sp. and E. purpurascens were not found to be saprophytic on fruit. Isolates of Alternaria sp., Bacillus sp., E purpurascens, pestalotia sp., Pseudomonas sp. and T. harzianum significantly inhibited germination and germ tube elongation of B. cinerea conidia in vitro in a nutrient solution, over a 24 h period. For example, the presence of Alternaria alternata A6 spores in a nutrient solution reduced germination of B. cinerea conidia from 100% to 20%. The presence of E purpurascens A77 spores inhibited B. cinerea conidial germ tube elongation from >840 pm (in control conidia) to 27 µm. The presence of any one of the BCAs tested prevented germination of B. cinerea conidia in a non-nutrient water solution, in comparision to germination of up to 86% in controls. A spore or cell suspension of each of the isolates Bacillus sp.M60, E. purpurascens A77 and T. harzianum C65 were spray inoculated onto kiwifruit blossoms produced in vivo in the glasshouse, immediately prior to inoculation of the blossoms with a condial suspension of B. cinerea. Application of the BCAs were completely effective in preventing colonization of blossoms by B- cinerea conidia. The effectiveness of each of the isolates E. purpurascens A77,T. harzianum C65 and either Bacillus sp.M60 or M53 to reduce the viability of sclerotia of B. cinerea and S. sclerotiorum was tested in soil punnets. A spore or cell suspension of each respective BCA was applied to the surface of replicated punnets that were seeded with either B. cinerea or S. sclerotiorum. Following 8 weeks incubation, punnets were harvested and viability of sclerotia assessed. T. harzianum C65 and Bacillus sp. M60 significantly reduced the viability of B. cinerea sclerotia from 8 sclerotia/punnet (control) to 4 sclerotia/punnet. T. harzianum C65 and E. purpurascens A77 caused a significant reduction in apothecia production of S. sclerotiorum, from 2.7 apothecia/punnet (control) to 0.7 apothecia/punnet. Bacillus sp.M8 and E purpurascens A77 were tested for their ability to reduce Botrytis stem end rot and Sclerotinia field rot in a kiwifruit orchard. The isolates tested did not successfully reduce either disease. Possible explanations for this are discussed. In order to monitor the survival of particular isolates of BCAs in the field, a technique was developed to distinguish between individual strains of a BCA species. The polymerase chain reaction (PCR) was utilized to identify DNA polymorphisms within the genome of T. harzianum C65, in comparison with other strains of Trichoderma spp.. A sequence of polymorphic DNA was cloned, sequenced and used as a hybridization probe in southern blotting to enable T. harzianum c65 to be distinguished from other strains of Trichoderma spp.. From the results obtained in this study, it was considered that Bacillus M60, E purpurascens 477 and Pseudomonas M30 were the best isolates for the biological control of Botrytis stem end rot on kiwifruit. Further work to enable application of these isolates as postharvest BCAs is discussed. Of the isolates tested in this study, T. harzianum C65 was considered the best isolate for use against Sclerotinia diseases on kiwifruit. Methods of selecting more effective BCAs against S. sclerotiorum are discussed.

There has been a move in the kiwifruit industry to pollinate by machine, allowing orchardists flexibility in timing, and other advantages. The traditional pollinators, bees, are unreliable and are susceptible to diseases such as the varroa mite. No measurements have been done on the efficiency of single-flower collection of pollen and the influence of airjet characteristics, to put this activity on a firm quantitative basis. For predictive purposes, a robust model of pollen behaviour around a single Green kiwifruit flower (Actinidia deliciosa) was built in this study by using a commercial computational fluid dynamics (CFD) package. The theoretical study first looked at the wind pollination of flower buds at different opening stages. Within the range of draft velocity recorded in the orchards, stigma are predicted to capture more pollen in a wind approaching from the front than from the side and back. Also, the pollen deposition on stigma increases as the bud opens wider and loses its petals. An estimation based on the predicted pollen collection efficiency indicated that wind pollination alone is insufficient to produce a minimum exportable fruit, which is in agreement with the observations reported in the literature. The question whether kiwifruit is a wind-pollinated plant is also discussed. Experimental checks of the modelling were carried out. Visualization of flow paths around a real kiwifruit flower in a wind tunnel compared well with the CFD predictions. The machine pollination employs a jet of air. CFD simulations of pollen-loaded air jets were carried out to study the effect of different jet-nozzle configurations, namely the jet direction onto the flower, nozzle-to-flower distance, diameter of nozzle and initial jet velocity. A frontal spray gives the most efficient pollen delivery to the stigma. Further gain is accomplished by introducing the pollen cloud closer to the flower, from a smaller nozzle and at higher initial jet velocity. These trends, except for that of nozzle size, have been validated experimentally through the pollen spraying of single real kiwifruit flower in the laboratory. Recommended ways of airjet spraying are suggested based on the CFD results. From the stigma collision efficiency, it is more advantageous to apply pollen when most of the flowers have lost their petals. Additional inclusion of an electrostatic influence into the pollen-loaded air jet simulations indicate that corona charging, but not tribo-charging, gives enhanced pollen collection by the stigma. The enhancement depends on the strength of electric field established between the nozzle and the flower. The spraying tests with tribo-charged pollen in laboratory indicated that an improved pollen collection may be possible with a greater charging of pollen. The benefit however was not realized consistently in all experimental conditions. The simulations assumed complete stickiness i.e. complete capture of pollen by the stigma on collision. This study also measured the force necessary to remove pollen in contact with stigma. The stickiness measurements of the stigma of Gold and Green kiwifruit flowers found that both flowers have equally sticky stigma. Stickiness increased with the aging of flowers. A reason is proposed related to the sugar in the exudate film. Overall, the variation of stickiness was statistically insignificant during the day. However, some older stigma were found to be stickier in the afternoon, which is in contrast to the general view that stigma are stickier in the morning. The gain in stickiness by the older stigma supports the recommendations for carrying out machine pollination after the petal fall. The last section of the work was done in an orchard, and studied the characteristics of large jet spraying (without pollen) at the T-bar and pergola trained vines. Recommendations on the designs of jet have been provided.

New Zealand is currently the third largest global producer of kiwifruit and thus plays an important role in the international market. Exports of kiwifruit are also of significant horticultural value for New Zealand and in 2007 the kiwifruit industry accounted for export values of NZ$790 million. The global kiwifruit market has experienced substantial changes in recent years and is likely to change significantly in the near future due to developments in production sources, adjustments to trade policy settings and shifts in consumer preferences. The New Zealand kiwifruit industry needs to consider what the impacts of these changes might be so that future strategies can be constructed effectively. Little quantitative modelling has been done in New Zealand to consider the impacts of changes to the global kiwifruit industry. The major contribution of this research was the development and calibration of a kiwifruit industry-specific partial equilibrium trade model. The model was then used to examine the impacts on New Zealand producers of these trade-related changes in the global kiwifruit market. Three relevant scenarios were developed for this purpose. They include a drop in EU demand through the introduction of a stricter Sanitary and Phytosanitary policy, an expansion of the Chinese kiwifruit industry where production is doubled by year 2013 and finally a trade liberalisation scenario where current import tariffs on kiwifruit were removed worldwide. It is clearly observed, through both the Chinese expansion scenario and the trade liberalisation scenario, what a potential impact and future role China has as a world market player. Increased availability of Chinese kiwifruit appears to affect New Zealand producer returns and exported quantities negatively, albeit not as significantly as the EU introduction of an SPS policy. A trade liberalisation scenario, on the other hand, proves to increase New Zealand grower returns significantly for all varieties.

Studio delle proprietà tecnologiche e funzionali di snack essiccati a base di kiwifruit Per diminuire i volumi di scarto di Actinidia chinensis cv. Jintao causati da standard estetici, in questo lavoro di tesi è stato studiato lo sviluppo di un nuovo prodotto partendo dalla purea di kiwifruit a polpa gialla alla quale sono stati aggiunti altri prodotti ortofrutticoli ed eventualmente saccarosio o trealosio, fino ad ottenere degli snack funzionali ad elevato valore nutritivo. Gli effetti benefici derivano principalmente dall’elevato contenuto di acido ascorbico degli ingredienti. L’agar è un polisaccaride che è stato aggiunto alla purea base per il suo potere addensante, conservante e stabilizzante. Dopo aver pensato a tre formulazioni con differenti ingredienti, i campioni sono stati sottoposti a liofilizzazione o essiccazione, in modo da ottenere due tipologie di prodotti entrambi stabili a temperatura ambiente. Dopodiché, i prodotti ottenuti a seguito dei processi di stabilizzazione sono stati caratterizzati dal punto di vista qualitativo (attività dell’acqua, contenuto in acqua, sostanza secca, colore e consistenza), nutrizionale (attività antiossidante con il metodo DPPH e ABTS, contenuto in polifenoli ed acido ascorbico) e sensoriale. I trattamenti di essiccazione riducono in parte le caratteristiche nutrizionali rispetto alla purea fresca tal quale, anche se i campioni liofilizzati, rispetto a quelli essiccati, hanno dimostrato di preservare meglio i composti antiossidanti, il contenuto in polifenoli ed in acido ascorbico. L’aggiunta di saccarosio o trealosio ha migliorato la durezza, e nei campioni dello snack contenente kiwifruit, finocchio e spinaci e in quelli liofilizzati contenenti kiwifruit, fragola, finocchio e succo di limone, svolgono un’azione protettiva dallo stress dei trattamenti di essiccazione sui composti antiossidanti. Dall’analisi sensoriale è emerso che i campioni liofilizzati contenenti saccarosio sono quelli maggiormente preferiti.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第22489号
農博第2393号
新制||農||1076(附属図書館)
学位論文||R2||N5269(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 近藤 直, 准教授 小川 雄一, 教授 飯田 訓久
学位規則第4条第1項該当

Tenderness, juiciness, colour and flavour are the most important meat quality attributes affecting the consumer acceptance. Maintaining the consistency of meat products by avoiding variable quality has become a major concern and great challenge to the meat industry. This in turn will also benefit meat end-users in the marketplace by having more tender meat. The present study was designed to evaluate the overall effects of pre-rigor infusion with kiwifruit juice, which contains the plant protease, actinidin, on lamb quality. A total of 18 lambs (12 months old) were divided into three treatment groups (6 lambs per each treatment). After exsanguination, lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and compared with a noninfusion treatment which acted as a control (C). Samples from different muscle/cuts (longissimus dorsi (LD) vs leg chops) at different post-mortem times (1 day post-mortem vs. 3 wks vacuum packaged storage at 2°C) and display time (0 to 6 days after the post-mortem storage) were analysed to monitor the changes on meat physical properties (e.g., tenderness, temperature, drip and cooking loss, colour), biochemical changes (pH, proteins and lipids) and volatile flavour compounds after the infusion treatments. The most tender meat (lowest shear force values) (P < 0.001) detected in the Ac carcasses post-mortem compared with C and W carcasses demonstrated that kiwifruit juice was a very powerful meat tenderizer, and could contribute to the meat tenderization process efficiently and effectively. Compared with C and W carcasses, the enhanced proteolytic activity (P = 0.002) resulting from the actinidin in kiwifruit juice in Ac carcasses caused degradation of the myofibrillar proteins and the appearance of new peptides during postmortem ageing. A slight positive effect in a*-value (redness) and decreased lipid oxidation, found in leg chops, was thought to be caused by the natural antioxidants in kiwifruit juice. Kiwifruit juice infused into the meat did not alter (P > 0.05) the volatile flavour compound profile indicating that the meat from Ac treated carcasses maintained its natural lamb flavour. No treatment differences were found for the temperature decline (P > 0.05) between the infused treatments and C. The higher rate of pH decline (P < 0.05) found in W carcasses might have contributed to the higher drip and cooking loss. The unbound water in meat might contribute to the higher L*-values (lightness) found in W carcasses. In summary, the proteolytic tenderizing infusion treatment using kiwifruit juice is a feasible approach for the commercial meat industry to increase profits, and also could satisfy the eating quality standards required by the consumers. In addition, tenderizing meat by using kiwifruit juice could also provide the kiwifruit processors an additional option for use of their product to gain a more profitable return.

The importance of European honey bees in improving fruit set, yield and fruit weight of kiwifruit on the central east coast of Australia was investigated. Field investigations were carried out using different bee saturations and different types of male pollen parents. These investigations confirmed the importance of honey bees in kiwifruit fruit set, yield and fruit weight. However, the results suggested that increasing bee activity alone may not increase pollination of kiwifruit by honey bees. Many factors need to be understood before introducing bees into the orchard. Bees were more effective during the early part of the flowering period, and bee activity varied according to the sex of the vine, planting design and the time of day. The type of male pollen parents also influenced fruit size and quality. Flowers pollinated by different pollen parents were assessed for pollen tube growth and histochemical changes. The resulting fruit were also examined for weight and seed numbers. Honey bees play the major role in the size and yield of kiwifruit, but the design of male vines, their age and type of male pollen may also contribute. The kiwifruit pistil also possesses important features that can be considered as adaptations to insect pollination.
Doctor of Philosophy (PhD)

La crescente tendenza dei consumatori a ricercare alimenti con alto contenuto funzionale ed elevata shelf-life ha stimolato la ricerca verso lo sviluppo di tecnologie innovative stabilizzanti. Tra i possibili trattamenti applicabili, risultano interessanti le alte pressioni di omogeneizzazione (HPH), anche per il riutilizzo di scarti e sottoprodotti dell’industria agro-alimentare. Infatti, essi sono una matrice ricca di sostanze ad elevato valore nutrizionale e funzionale, come gli antiossidanti, i polifenoli e l’acido ascorbico. L’obiettivo di questo lavoro di tesi è stato quello di valorizzare i kiwifruit a polpa gialla sottodimensionati (e quindi considerati scarti) per la creazione di una purea di frutta composta da kiwifruit, finocchio e limone. Tale purea è stata sottoposta ad HPH come trattamento stabilizzante, con o senza l’utilizzo di un trattamento termico blando (HPH, HPH in aggiunta a trattamento a 70°C (T+HPH) e con solo trattamento termico più intenso (a 97°C per 25 minuti (T)), per la valutazione della stabilità e della qualità chimico-fisica, microbiologica e nutrizionale in rapporto ad un campione non processato. In aggiunta si sono effettuati inoculi di microrganismi patogeni (L. monocytogenes, E. coli, S. enteritidis, B. cereus) e degradativi (S. cerevisiae e L. plantarum) con lo scopo di valutare l’idoneità dei trattamenti applicati nella matrice in oggetto e per analizzare l’andamento di tali microrganismi durante la shelf-life. Dalle analisi effettuate si è osservato un cambiamento del colore per il campione T, mentre il trattamento T+HPH è risultato ottimale fino al 64 giorno di conservazione a temperatura ambiente. L’attività antiossidante è risultata migliore nel campione T, mentre il contenuto di acido ascorbico è diminuito in ogni campione. Dal punto di vista microbiologico, tutti i trattamenti hanno abbattuto i MO patogeni eccetto il B. cereus, per il quale solo il trattamento termico è risultato efficace.

Lo scopo di questa tesi è stato quello di sviluppare un nuovo prodotto, fette di kiwifruit essiccate, a partire dai frutti sotto calibro della varietà Jintao, con lo scopo di valorizzare i frutti considerati scarti, in quanto non conformi agli standard commerciali. I campioni prima dell’essiccazione a tre diverse temperature (50 – 60 – 70°C) hanno subito trattamenti PEF (campi elettrici pulsati) ed OD (disidratazione osmotica) singolarmente o combinati tra loro. Di ciascun campione è stata valutata la cinetica di essiccazione e successivamente i prodotti sono stati caratterizzati dal punto di vista qualitativo (contenuto in acqua, sostanza secca, attività dell’acqua, colore e texture) e dal punto di vista nutrizionale (attività antiossidante, contenuto di polifenoli totali ed acido ascorbico), ed in fine è stata effettuata un’analisi sensoriale. I risultati ottenuti hanno dimostrato come i pre-trattamenti, campi elettrici pulsati (PEF) e osmosi diretta (OD), possano diminuire i tempi di essiccazione e come l’effetto combinato di tali per-trattamenti possa incidere sui vari parametri investigati. Tutti i campioni ottenuti hanno mantenuto un colore giallo tipico del kiwifruit Jintao. La croccantezza dei campioni è risultata più elevata nei campioni essiccati a 70°C, in particolare nei campioni Controllo e in quelli trattati con PEF e successivamente OD. Dall’analisi sensoriale è emerso un maggiore gradimento per lo snack ottenuto con la combinazione dei pre-trattamenti OD/PEF e PEF/OD rispetto agli altri. Considerando complessivamente sia i risultati delle analisi qualitative che dell’analisi sensoriale, l’utilizzo del trattamento PEF e OD può rappresentare valide soluzioni per l’ottenimento di fette di kiwifruit essiccate con un buon livello di qualità e contemporaneamente una buona gradevolezza complessiva da parte di potenziali consumatori.

Nutrigenomics is the study of interactions between diet and human genotype with the aim of understanding how food components influence gene and protein expression, and of linking this interaction to differences in individual metabolism. Inflammatory Bowel Disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract involving inappropriate immune response to commensal microorganisms in a genetically susceptible host. The principal aim of the research described here was concerned with determining if aqueous and ethyl acetate extracts of gold kiwifruit (Actinidia chinensis) or green kiwifruit (Actinidia deliciosa) had immune modulating effects against inflammatory processes known to be increased in patients with IBD. This aim involved the use of in vitro and in vivo models of IBD that were studied at the molecular level. The first part of the research examined the anti-inflammatory properties of four kiwifruit extracts (KFEs) in in vitro IBD models. These models comprised primary macrophages and intestinal epithelial cells isolated from C57BL/5J or interleukin 10 gene deficient (Il10-/-) mice and RAW 264.7, a transformed murine macrophage-like cell line. All four KFEs reduced the production of the pro-inflammatory biomarker nitric oxide and of both pro- and anti-inflammatory cytokines after cells were stimulated with lipopolysaccharide. Ethyl acetate extracts exhibited greater inhibitory activity compared to aqueous extracts for each type of kiwifruit. In the second part of the research, KFEs were used as a dietary intervention in Il10-/- mice, which are an in vivo model of IBD. While all Il10-/- mice developed significant colonic inflammation compared to the C57BL/6J background strain, this was not affected by the inclusion of KFE in the diet. Whole genome gene and protein expression level profiling indicated that KFEs influenced immune signalling pathways and metabolic processes within the colonic tissue; however, the effects were subtle. These findings highlight the importance of investigating food components identified by cell-based screening assays with appropriate animal models and human clinical studies to confirm and understand their activity. While KFE anti-inflammatory activity was not confirmed in our IBD mouse model, the molecular effects identified may represent immune modulating effects that are beneficial to other inflammatory disorders.

Orientador: Hilary Castle de Menezes
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-04T04:09:07Z (GMT). No. of bitstreams: 1 Buchweitz_PauloRenato_D.pdf: 3265983 bytes, checksum: 57291d57e5ec02775a2fcdf1204dd61a (MD5) Previous issue date: 2005
Resumo: Em algumas regiões do Brasil a cultura do kiwi encontrou bom potencial para o seu desenvolvimento. A cultivar Hayward destaca-se pela produção de frutos com elevada qualidade no sabor, tamanho, conservação e valor nutricional. Até o momento a maioria das pesquisas pós-colheita esteve voltada a conservação pelo frio, em virtude da elevada susceptibilidade deste fruto a alterações físico-químicas e sensoriais decorrentes dos métodos convencionais de conservação. Este trabalho procurou avaliar os efeitos da pré-secagem osmótica em parâmetros de qualidade de fatias de kiwi secas, congeladas, liofilizadas e pasteurizadas. Os frutos para a execução dos experimentos foram adquiridos diretamente de pomar comercial localizado em Campos do Jordão-SP. Inicialmente foi realizada uma avaliação da pré-secagem osmótica de fatias de kiwi de 10-11mm de espessura sob condições de processo pré-estabelecidas: imersas em solução de sacarose a 65% a 40°C por 15, 60, 120, 180 e 240 minutos com agitação em shaker a 75 oscilações horizontais e amplitude de 1cm, utilizando fruta em solução de sacarose na proporção de 1:4. Os produtos obtidos foram avaliados sensorialmente e verificou-se que a condição correspondente a duas horas de processo foi a melhor aceita, sendo este resultado posteriormente considerado no estudo dos métodos convencionais. Na secagem com circulação forçada de ar aquecido a 40°C até 25% de umidade residual a pré-secagem osmótica proporcionou em média uma redução de 10% no tempo necessário ao processo e melhor aparência, aroma característico e maior firmeza das fatias após a reconstituição com água e açúcar. No estudo do osmo-congelamento por meio da avaliação dos métodos de congelamento por ar estático, contato em placas ou imersão em nitrogênio líquido, foi constatado que a prévia desidratação osmótica exerceu maior influência do que os diferentes métodos de congelamento nos níveis estudados na redução do líquido exsudado e no aumento da firmeza após o descongelamento. O tratamento prévio também contribuiu para melhorar a aparência geral e intensificar a coloração esverdeada. Na avaliação dos efeitos dos referidos métodos de congelamento nos experimentos de osmo-liofilização foi observado que o tratamento prévio em solução de sacarose não promoveu redução no tempo necessário à liofilização. No entanto, proporcionou melhora na textura e coloração das fatias, enquanto que a quantidade de água reincorporada às fatias foi mais influenciada pelos métodos de congelamento. Os produtos em calda processados com fatias submetidas a pré-secagem osmótica apresentaram aceitação sensorial similar quanto ao aroma e sabor e aceitação melhor quanto a aparência e textura durante o armazenamento, comparativamente aos produtos processados com fatias não submetidas ao tratamento prévio. O aproveitamento do xarope da pré-secagem osmótica como líquido de cobertura pode contribuir para a redução de custos no envase de fatias de kiwi em calda
Abstract: Mastitis is an inflammatory reaction of the mammary gland, caused by pathogenic bacteria, resulting in increased number of somatic cells of milk. Milks with high somatic cells count (SCC) present alterations in the composition, influencing, therefore, the quality of processed dairy products. The objective of this work was to evaluate the effect of milk SCC on the development of microorganisms and sensorial characteristics, during ripening of Prato cheese. Two groups of animals were selected to obtain milk with low (< 200.000 cell/ml) and high (> 700.000 cell/ml) SCC. Centesimal composition of cheeses was evaluated after processing and after 6, 12, 19, 35 e 54 days of storage for lactic bacteria, psychrotrophs, total bacteria count, yeasts and moulds counts. A factorial arrangment of treatments 2 x 5 in a completely randomized blocks was used. The effect of SCC (2 levels of variation) and storage time (5 levels of variation) on studied variables was evaluated by ANOVA and Tukey?s test at 5% of significance. The cheeses sensory evaluation was carried out through firmness, flavor and of lavors using ideal scale of nine points and general acceptance was evaluated by hedonic scale of nine points. The sensory evaluations were carried out after 7, 21, 34, 48 and 61 days of storage. Milk with high SCC had higher pH than milk with low SCC. Cheeses obtained from high SCC milk showed higher moisture than cheeses with low SCC. SCC affected lactic bacteria and psychrotrophs counts, as higher levels were found in low SCC cheeses. Total count bacteria, lactic acid and psychrotrophs counts decreased during storage, while yeasts and moulds count increased, independently of milk SCC. The sensory evaluation showed lower general acceptance to high SCC cheeses when compared with low SCC cheeses
Doutorado
Tecnologia de Alimentos
Doutor em Tecnologia de Alimentos

Kiwi Frutix, es un snack saludable con frutos deshidratados, bañados de miel y Kiwicha, 100% orgánico, libre de preservantes, gluten, colorantes, sal, azúcar y otros aditivos. Asimismo, es una excelente opción para las loncheras escolares y como un aperitivo, siendo un aliado perfecto para madres de familia con hijos en edad escolar. Para poner en marcha nuestro proyecto requerimos 41,245.48 soles, con una estructura de financiamiento donde los accionistas e inversionistas participan con 50% cada uno. Consideramos que Kiwi Frutix es un producto exportable, con gran potencial de consumo en mercados europeos y norteamericanos, debido a la tendencia mundial de consumir alimentos naturales y que combatan la obesidad. Estimamos que el proyecto tendrá un VAN financiero S/. 84 321.42 y un TIR de 59%.Y creemos que tendrá aceptación en el mercado y que los planes de marketing que proponemos ayudarán al total éxito de nuestras ventas.
Kiwi Frutix, is a healthy snack with dehydrated fruits, bathed in honey and Kiwicha, 100% organic, free of preservatives, gluten, dyes, salt, sugar and other additives. It is also an excellent option for school lunch boxes and as an appetizer, being a perfect ally for mothers of families with children of school age. To start up our project, we require 41,245.48 soles, with a financing structure where shareholders and investors participate with 50% each. We believe that Kiwi Frutix is an exportable product, with great potential for consumption in European and North American markets, due to the global tendency to consume natural foods and combat obesity. We estimate that the project will have a financial NPV S /. 84 321.42 and an IRR of 59%. And we believe that it will be accepted in the market and that the marketing plans we propose will help our sales succeed.
Trabajo de investigación

Kiwifruit are of huge economic importance for New Zealand representing 29 percent of total horticultural exports. Fruit size is the biggest determinant of what consumers are willing to pay, and there is also a positive relationship between consumer preference for flavour and percentage dry matter. The two main cultivars exported from New Zealand are Actinidia chinensis ‘Hort 16A’ (gold kiwifruit) and A. deliciosa ‘Hayward’ (green kiwifruit). Under current commercial practice the only product allowed for use on kiwifruit to increase fruit size in New Zealand is Benefit®. Benefit® has been shown to induce different results when applied to A. chinensis and A. deliciosa, whereas synthetic plant growth regulators such as the cytokinin-like substance N-(2- chloro-4-pyridyl)-N’-phenylurea (CPPU) have been found to promote similar increases in fresh weight of fruit in both cultivars. Final fruit size is determined by both cell division and cell enlargement. It was been shown that fresh weight can be increased in both of the major Actinidia cultivars even though their physiology differs. Hormonal control of fruit size in relation to cell division and cell enlargement phases of fruit growth was studied in both A. chinensis and A. deliciosa. CPPU was applied to both cultivars in a growth response experiment where fruit were collected throughout the growing season. The objective of this experiment was to create growth curves, to compare and contrast the effect on A. chinensis and A. deliciosa, and to provide material for hormone analysis. Application of CPPU was found to significantly increase the fresh weight of both A. chinensis and A. deliciosa fruit (46.98 and 31.34 g increases respectively), and alter the ratio of inner and outer pericarps of A. chinensis fruit. CPPU and Benefit® were applied individually and together to both cultivars. It was found that only A. chinesis fruit were affected by the application of Benefit®; fresh weight was increased by 26.38 g, and percentage dry matter was significantly reduced. There was a statistically significant (p < 0.05) interaction between CPPU and Benefit® when applied to A. chinensis. 3,5,6-trichloro-2-pyridyloxyacetic acid (3,5,6-TPA) was applied to A. deliciosa on two application dates at three concentrations and was found to decrease fresh weight of fruit, but significantly increase percentage dry matter regardless of application date or concentration. Lastly CPPU and 1-naphthalene acetic acid (NAA) were applied to A. deliciosa at two application dates and in all combinations. Application date affected the response to both a low concentration of CPPU and NAA. A synergistic interaction was observed when CPPU was applied early plus NAA late (CPPU early (4.53 g increase) plus NAA late (13.29 g) < CPPU early plus NAA late (33.85 g). Finally endogenous hormone content was studied. Methods were developed and tested for the simultaneous analysis of both indole-3-acetic acid (IAA) and cytokinins. Freeze dried fruit were purified using Waters Sep-pak® cartridges and Oasis® columns then IAA was quantified by high pressure liquid chromatography. Preliminary results indicate a correlation between application of CPPU and endogenous IAA, high concentrations of IAA correlated well with periods of rapid fruit growth particularly for CPPU treated fruit.

Italy has a preeminent rank in kiwifruit industry, being the first exporter and the second largest producer after China. However, in the last years kiwifruit yields and the total cultivated area considerably decreased, due to the pandemic spread of the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). Several climatic conditions and cultural practices affect the development of the bacterial canker. This research work focused on the impact of agricultural practices and microclimate conditions on the incidence and epidemiology of Psa in the orchard. Therefore, the effect of fertilization, irrigation, use of bio-regulators, rootstock, training system and pruning were examined. The effect of different tunnel systems was analyzed as well, to study the plant-pathogen interaction. Considering the importance of insects as vectors in other pathosystems, the role of Metcalfa pruinosa in the spread of the bacterial canker was investigated in controlled conditions. In addition, quality and storage properties of fruits from infected plants were assessed. The study of all these aspects of the agronomic practices is useful to define a strategy to limit the bacterial diffusion in the orchard. Overall, excess nitrogen fertilization, water stress, stagnant water supplies, pruning before summer and the high number of Metcalfa pruinosa increased the Psa incidence. In contrast, tunnel covers may be useful for the control of the disease, with special attention to the kind of material.

Italy has a preeminent rank in kiwifruit industry, being the first exporter and the second largest producer after China. However, in the last years kiwifruit yields and the total cultivated area considerably decreased, due to the pandemic spread of the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). Several climatic conditions and cultural practices affect the development of the bacterial canker. This research work focused on the impact of agricultural practices and microclimate conditions on the incidence and epidemiology of Psa in the orchard. Therefore, the effect of fertilization, irrigation, use of bio-regulators, rootstock, training system and pruning were examined. The effect of different tunnel systems was analyzed as well, to study the plant-pathogen interaction. Considering the importance of insects as vectors in other pathosystems, the role of Metcalfa pruinosa in the spread of the bacterial canker was investigated in controlled conditions. In addition, quality and storage properties of fruits from infected plants were assessed. The study of all these aspects of the agronomic practices is useful to define a strategy to limit the bacterial diffusion in the orchard. Overall, excess nitrogen fertilization, water stress, stagnant water supplies, pruning before summer and the high number of Metcalfa pruinosa increased the Psa incidence. In contrast, tunnel covers may be useful for the control of the disease, with special attention to the kind of material.

Total soluble solids (TSS) is a reliable indicator of melon eating quality, with a minimum standard of 10% recommended. The state of Australian melon production with respect to this quality criterion was considered within seasons, between growing districts and over seasons. It was concluded that improvement in agronomic practice and varietal selection is required to produce sweeter melons. The scientific literature addressing melon physiology and agronomy was summarised, as a background to the work that is required to improve melon production practices in Australia. The effect of source sink manipulation was assessed for commercially grown and glasshouse grown melon plants. The timing of fruit thinning, pollination scheduling, the application of a growth inhibitor and source biomass removal were assessed in relation to fruit growth and sugar accumulation. Results are interpreted against a model in which fruit rapidly increase in weight until about two weeks before harvest, with sugar accumulation continuing as fruit growth ceases. Thus treatment response is very dependant on timing of application. For example, fruit thinning at 25 days before harvest resulted in further fruit set and increased fruit weight but did not impact on fruit TSS (at 9.8%, control 9.3%), while thinning at 5 days before harvest resulted in a significant (Pless than 0.05) increase in fruit TSS (to 10.8%, control 9.3%) and no increase in fruit weight or number. A cost/ benefit analysis is presented, allowing an estimation of the increase in sale price required to sustain the implementation of fruit thinning. The effect of irrigation scheduling was also considered with respect to increasing melon yield and quality. To date, recommended practice has been to cause an irrigation deficit close to fruit harvest, with the intent of 'drying out' or 'stressing' the plant, to 'bring on' maturity and increase sugar accumulation. Irrigation trials showed that keeping plants stress-free close to harvest and during harvest, facilitated the production of sweeter fruit. The maintenance of a TSS grade standard using either batch based (destructive) sampling or (non-invasive) grading of individual fruit is discussed. On-line grading of individual fruit is possible using near infrared spectroscopy (NIR), but the applicability of the technique to melons has received little published attention. Tissue sampling strategy was optimised, in relation to the optical geometry used (in commercial operation in Australia), both in terms of the diameter and depth of sampled tissue. NIR calibration model performance was superior when based on the TSS of outer, rather than inner mesocarp tissue. However the linear relationship between outer and middle tissue TSS was strong (r2 = 0.8) in immature fruit, though less related in maturing fruit (r2 = 0.5). The effect of fruit storage (maturation/senescence) on calibration model performance was assessed. There was a negligible effect of fruit cold storage on calibration performance. Currently, the agronomist lacks a cost-effective tool to rapidly assess fruit TSS in the field. Design parameters for such a tool were established, and several optical front ends compared for rapid, though invasive, analysis. Further, for visualisation of the spatial distribution of tissue TSS within a melon fruit, a two-dimensional, or hyper-spectral NIR imaging system based on a low cost 8-bit charge coupled device (CCD) camera and filter arrangement, was designed and characterised.

碩士
國立中興大學
園藝學系
88
Seed germination of A.arisanensis, A.latifolia, and A.setosa, were accelerated by stratification at 5℃ for 30, 40, and 60 days, respectively. The response of seed to stratification was significantly depended on seed source. seeds from high altitude, A. setosa did not germinate if stratification was absent, but seeds from low altitude, A. arisanensis germinated well after stratification for 30 days. The seed chilling requirement of A.setosa is higher than that of A. latifolia or A. arisanensis. The germination rate of A.arisanensis, A.latifolia, and A.setosa seed without chilled, were significantly promoted by treating GA3. Treatment with GA3 2000ppm resulted in increased germination rate up to 68.4, 52.9, and 26.8%, respectively. GA3 also reduced seed germination period. High concentration of GA3 treatment for 24hrs also enforced germinating vigor. 30℃ is better for the seed germination of A.arisanensis and A.latifolia, while A.setosa are 25℃. In this experiment the germination of Actinidia seed was delayed by 15℃ incubation.

碩士
國立中興大學
園藝學系所
95
The characters of four wild kiwifruit species in Taiwan were investigated in this study. The wild kiwifruits in Taiwan present great diviation in genotype and phenotype. For example, the shape of Actinidia setosa fruit varies from near globose、 ovoid to flate globose；fresh color varies form yellow-green、jade-green to green with red core. The average total soluble solid contains from 10.2 °Brix to 16 °Brix. The most tasty A. setosa plant can be used to further selection. Wild A. callosa plants in Taiwan were found in mountains with different elevation from 400m、1200m and 1800m. We found out that these 3 populations could nomally grow and bear fruit in their own region, but their dormancy characteristic are quite different. In the experiment, A. callosa seeds collected from low attitude even needn’t stratification, and the germination rate can reach 20％. This machinism is very important of them to suit much hotter condition in their own region. In the other way, seeds collected from high land must be suffered 3 weeks or more cold stratification to break winter dormancy. Similar result happened in excised cane test which dormant shoots were collected wildly in November. The seeds taken from wild were breed in NCHU and later planted at Wu-Fung low land for heat resistant test. We obtained that plants originally germed from low attitude has larger leaves, longer shoot average length at the end of the research than plants from high land. In the opposite, plant from high land had smaller leaves and lots of shorter shoots. The photosynthesis ability was low correlated with different population and leave surface temperature, but much correlated with group inter-differences and leave stomatal aperture. It means that we could find plants with high photosynthesis rate in every population, and even these plants are suffering the heat stress, photosynthesis rate will still be high if the stomata can normally open. In the high altitude race, some plants show high photosynthesis rate but have shorter shoots and small leaves. This may be the result of the assimilation balance interfered by high temperature that causes the presence of numorous autumn shoots, which compete for the energy source with each other.

碩士
國立中興大學
園藝學系所
101
Kiwifruits (Actinidia spp.) are deciduous vines that mostly indigenous to temperate areas with the following problems when cultured in subtropical low lands: inadequate winter chilling may cause limited budbreak in the next season, high temperature may induce abnormal growth in summer and delay natural defoliation and onset of dormancy in autumn. Therefore, the main goals of this study are to overcome the the problem of inadequate winter chilling by grafting and bud-forcing of low-land kiwifruit vines, to evaluate the effect of high temperature on the growth of kiwifruits, and to test the potential of artificial defoliation to induce onset of bud dormancy. Results from this research may possibly be applied to culture kiwifruits in subtropical low lands. The plant materials include eight cultivars or individuals in three species(A. deliciosa: ‘Abbott’, ‘Bruno’, ‘Chung-Hsing No. 3’, ‘Tomuri’, ‘Matua’, and a female individual‘E’. A. chinensis: a male individual‘F’. A. setosa: ‘An-Ma No. 9’). The stock plant species is A. rufa. Our results indicated that the grafted scions start to bud two weeks after grafting. The period between budbreak and flowering is 1-4 weeks shorter in low-land trees than that of high-land trees. The high-land flowering often encounters the rainy season, causing the subsequent poor fruitset. The flower number of the low-land grafted scion is fewer, but the percentage of fruitset is higher. As to the fruit quality, the total soluble solids were less in the fruit grown at low land. No significant differences in fruit weight, firmness, and titratable acid can be observed between low- and high-land trees. Treatment of 10 fold diluted DormexR alone or in combination with nicking has no significant effect on budbreak of high-land kiwifruits. For the low-land trees, the best treatment for budbreak was nicking followed by treatment of 20% calcium cyanamide hydrolyzed solution, the second was nicking followed by treatment of 20% garlic extract, the third is nicking and then treated with 10 fold diluted DormexR, next is the 10 fold diluted DormexR treatment without nicking. All these treatments showed a positive effect on budbreak relative to the control. For the bud-forcing in a low-land greenhouse, nicking treatment showed a stronger effect on budbreak than treatment with 10 fold diluted DormexR. The time required for budbreak of low-land trees is about 20 days earlier than that of high-land trees. The period between budbreak and flowering is about 20 days less for low-land trees compared to that of high-land trees. Flowers per shoot in most cultivars were significantly less for low-land trees in contrast to that of high-land trees. Results from bud analysis indicated that respiration rate of the bud increased 18-36 hours after treatment in all treatments. An ethylene peak was also observed after treatment with 10% 2-chloroethanol or 20% calcium cyanamide hydrolyzed solution. Ascorbate peroxidase activity was elevated 24 hours after most of the treatments. For catalase activity, except for the buds treated with 10 fold diluted DormexR showing a decline 48 hours after treatment, the rest first showed a decline followed by an increase. In terms of peroxidase activity, an increase followed by a decrease was observed in most treatments. The low-land kiwifruit plants grown under high temperature have a 25-60% fruit drop. The low- and high-land shoot length was not significantly different from each other. For the net photosynthetic rate, most cultivars grown at low land had a lower rate than those grown at high land. Total soluble sugar of leaves was higher in low-land trees, but the starch content was similar between low- and high-land trees. For the artificial defoliation timing, January is better than December or February. The earlier the plants were defoliated, the more soluble sugars can be accumulated in the buds.

碩士
國立中興大學
園藝學系
86
The soluble solids content and firmness of kiwifruit could be used as indexs of maturation and harvesting time . In this study, the firmness and soluble solids content of ''First Empire'' are 7.06 Kg ( tip：7.2 mm ) and 6.2 0 Brix, respectively, while those of ''Jiang See 8151'' are 6.68 Kg and 6.6 0 Brix, respectively.The ascorbic acid content of A. latifolia fruit at the young stage could be as high as 2688 mg / 100 g F W, then decreased to 1962 mg / 100 g F W and 1972 mg / 100 g F W during fruit developing stage.We found A. latifolia is one of the highest level in ascorbic acid, even higher than that of Malpighia glabra ( 1362 mg / 100 g F W ). For all organic acids, the content of quinic acid is the highest at the begining of fruit development, then it decreased, while the citric acid increased gradually at later growth stage. The major sugars included fructose、glucose and sucrose. The contents of fructose and glucose were higher than that of sucrose, but they all increased as fruit growing.In the study of storage, the content of ascorbic acid kept stable in cold ( 5 ℃ ) condition for 98 days, while declined dramatically in warm or room temperature. The level of other organic acids declined gradually during storage.The firmness of kiwifruit could be used as an index of storage stability. The soluble solids content is 6 - 7 0 Brix at physiological maturity and 12 0 Brix after storage. The sugar increased significantly, while the organic acids declined gradually after storage at room temperature. Actinidia latifolia, a Taiwan native kiwifruit, with super high content of ascorbic acid, growing widely in countryside ( 300 - 2200 m from sea level ) has great potential in horticulture.

碩士
義守大學
生物技術與化學工程研究所碩士班
97
This work is to establish the optimun for the extraction of kiwifruit seed oil by supercritical carbon dioxide. The free fatty acids composition in the oil is also identified by gas chromatography and by liquid chromatography. While one-factor-at-a-time experiment method was employed to study the effects of operating conditions on the extraction yield, the operating parameters were set in the range of 25~55 MPa, 45~60 ℃, 32~42 kg-CO2/h, 2.4~3.2 kg-loaded per batch, and 40~100 mesh. Furthermore, Taguchi Method (An L32 (21×49) orthogonal array) was also used to study the interaction effect among 6 variables. This study aimed to find the optimal extraction conditions for the Kiwifruit Seed Oil Recovery. From one-factor-at-a-time experiment method, it was found that the extraction pressure is the most significant factor on the extraction yield. The maximum yield of the extraction occurred while the operational variables were set at the following conditions: 55 MPa, 55 ℃, 38~39 kg/h, 2.8 kg per batch and ground to 60~80 mesh. By Taguchi Method, we studied the main effect and the variance. Results showed that optimal extraction yield was achieved when variables were set at the following parameters: operating condition for the extractor were 55 MPa and 60 ℃; for the 1’st separator were 5 MPa and 45 ℃; for the 2’nd separator 5 MPa and 30 ℃; and the flow rate and extraction time were 41 kg/h and 80 minutes. The optimal conditions from two methods are nearly identical with 38.8% of yield. This study also used GC to analyse free fatty acids of the oil and found that the composition is: Palmitic acid (7.04%), Stearic acid (0.40%), Oleic acid (14.30%), Linoleic acid (13.61%) and α-Linolenic acid (63.11%). Among these free fatty acids, the content of α-Linolenic acid is the richest. In addition, the total percentage of the unsaturated fatty acid in kiwifruit seed oil reaches 91.02%. By using GC, HPLC and GC/MS, this study also separated and indentified squalene from the oil. And the content can reach 2.57% of the oil. This implies that kiwifruit seed oil is a valuable gradient and worthy of further studies.

Tese de Doutoramento, Produção Vegetal, Unidade de Ciências e Tecnologias Agrárias, Universidade do Algarve, 1999
O kiwi (Acíinidia deliciosa A. Chev.) tem sido considerado um fruto climatérico. No entanto, este fruto comporta-se atipicamente em resposta à aplicação externa de etileno a várias temperaturas. A incapacidade do kiwi para produzir etileno a baixas temperaturas, a produção de etileno à temperatura ambiente após um período de frio. o limite máximo de temperatura para produção de etileno e o seu comportamento pósarmazenamento não estão suficientemente estudados. Nesta tese investigaram-se algumas características particulares do percurso da biossíntese do etileno e o amadurecimento do kiwi induzidos por propileno a temperaturas de 10 a 45ºC, após armazenamento a baixas temperaturas, assim como após armazenamento em atmosfera controlada (CA) e nível de oxigénio ultra baixo (ULO).
Kiwifruit (Acíinidia deliciosa A. Chcv.) is considcrcd a climactcric fruit. However, it bchaves atypically in response to externai ethylene application at different temperaturcs. The lack of ability of the kiwifruit to produce ethylene at low temperatures, its chilling requirements and maximum temperalure limil for ethylene production and its behaviour post-storagc are poorly understood. In this thesis were studied some particular features of the ethylene biosynthesis pathway and ripening of kiwifruit induced by propylene at temperatures from 10 to 45ºC, during shelf-life after chilling, as well as after storage in controlled atmosphere (CA) and ultra low oxygen (ULO) conditions.

碩士
國立雲林科技大學
財務金融系
107
Taiwan signed the first free trade agreement (FTA) with Panama since Jan, 2004. Thereafter, the FTA between Nicaragua, Guatemala, Salvador, Honduras, Singapore, New Zealand, Paraguay and Kingdom of Eswatini are also signed. However, when we look into the data of bilateral trade after those FTAs getting into effects, the trade deficit seems getting worse, and the surplus dropped considerably. Overall, it is not easy to define whether the FTAs are good for our economy or not. This research analyzes the trade deficits before and after the FTAs, price punctuation of the good traded, and a case study of Kiwi to explore the impact of FTAs on goods and welfares changes.

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This work was supported by funding FEDER through COMPETE, by National funding through Fundação para a Ciência e Tecnologia (FCT) and Marine Studies (CESAM).
Mestrado em Microbiologia

Pseudomonas syringae pv. actinidiae (Psa), is a Gram-negative bacterium, aerobic, motile, able to grow epiphytically and endophytically on plants, and it is the causative agent of kiwifruit bacterial canker. Cool temperature and high humidity promote the multiplication of this pathogen and increase the severity of plant disease. Psa can enter into its host plant through natural openings such as stomata and hydatodes or following mechanical wounding, and then spreads systematically into the whole plant. Psa strains are divided into 5 different biovars, based on the country of origin, the outbreak period, genomic characteristics, toxin production and the virulence. In particular, the biovar 1 was identified in Japan in 1984; the biovar 2 spread in Korea in 1997; the biovar 3, identified both in New Zealand and Italy in 2008-2010, is the causative agent of the last worldwide outbreaks and is recognized as the most virulent biovar; the biovar 4 identified in New Zealand, firstly classified as a low virulence Psa biovar, was re-assigned to another pathovar; finally, the biovar 5 and 6 were identified more recently in Japan but is not yet characterized. In the frame of the PhD project, we performed a microarray analysis in order to elucidate the differences in the transcriptomic profile among the Psa stains (biovar 1, 2 and 3), which could account for their different aggressiveness. Then, we focused on a class of proteins that play a role in signal recognition and transcription regulation called LuxR solos. Psa is characterize by three LuxR solos proteins, namely PsaR1, PsaR2 and PsaR3 which could be involved in the interaction between kiwifruit and Psa but whose role is not elucidate yet. Interestingly a bioinformatics analysis performed in our laboratory revealed that PsaR3-encoding gene is specific of biovar 3 and is localized on a plasmid, within a conserved cluster of genes. Furthermore, the cluster is characterized by the presence of an intergenic region that could play a role as bidirectional promoter and could be regulated by PsaR3 itself according to the predicted presence of cis-acting elements putatively regulated by LuxR proteins. Finally, an RNA-seq analysis revealed the Psa pathways regulated by PsaR3 and studies of promoter activities of the intergenic region which could be putatively regulated by PsaR3 revealed that this LuxR solo could recognize a signal molecule produced by kiwifruit, thus mediating an inter-kingdom communication and likely playing a crucial role in the host recognition and in the mediation of the high virulence of the biovar 3.

碩士
國立中興大學
園藝學系
93
The intention of this study were to establish the data of optimum harvest maturity and the best storage condition of newly breeding ‘Chung Hsing No. 4’ and ‘Chung Hsing No. 3’ kiwifruit to benefit popularization afterward. ‘Chung Hsing No. 4’ and ‘Chung Hsing No. 3’ kiwifruit were harvested from 21 weeks after anthesis, their total soluble solid content have approached 6.5～6.6°Brix, which reaches harvesting standard of the imported kiwifruit. Average fresh weight of ‘Chung Hsing No. 4’ reaches 82.2g and average fresh weight of ‘Chung Hsing No. 3’ reaches 69.4g respectively. To compete with imported kiwifruit, the domestic kiwifruits were harvested as late as possible to obtain higher quality with higher soluble solid content. ‘Chung Hsing No. 4’ kiwifruit stored at 1℃ is proper, and its total soluble solid content have approached more than 12.2°Brix. ‘Chung Hsing No. 4’ kiwifruit that was stored at 1℃ for 140 days was still able to ripen normally, and its total soluble solid content have approached 12.6°Brix, but fruits tasted may be sourer because its titratable acid reaches 1.25％. As long as Taiwan farmers culture ‘Chung Hsing No. 4’ and ‘Chung Hsing No. 3’ kiwifruit on mountain region to product fruit with high quality, they will not only reduce dependence on the imported kiwifruit but also find a way of mountain horticulture in Taiwan.