Academic literature on the topic 'Ripening'

The influence of drying and ripeninig conditions (traditional and industrial) in the production of dry fermented sausage Petrovsk? klob?sa, on fatty-acid composition and oxidative changes in lipids, during 7 months of storage, was investigated. During the storage period, the sum of unsaturated fatty acids and the content of free fatty acids were significantly higher (p<0.05), while the content of malondialdehyde was significantly lower in the sausage subjected to traditional conditions of drying and ripening. At the end of the storage period, contents of pentanal and hexanal in the sausage subjected to traditional conditions of drying and ripening (4.03 ?g/g and 1.67 ?g/g, respectively) were significantly lower (p<0.05) in comparison with these contents in the sausage subjected to industrial conditions of drying and ripening. Traditional conditions of drying and ripening at lower temperatures have led to lower oxidative changes in lipids in traditional dry fermented sausage Petrovsk? klob?sa during storage period.

HighlightsMeasurements of relaxation times in intact banana at micro-Tesla field was achieved.Bulk spin-spin relaxation time highly correlated with best descriptors of banana ripening.A basis for quasi-continuous distribution of spin-spin relaxation in banana was given.Abstract. Achieving fast, low-cost, and non-destructive internal quality testing techniques in the horticultural industry is a challenge. Developing techniques such as ultra-low field nuclear magnetic resonance (NMR) is a promising solution. Banana is a fast ripening fruit, which undergoes many changes in quality characteristics during ripening, and was chosen as a fit choice for extensive fruit quality study by NMR. A commercial NMR system using a superconducting quantum interference device (SQUID) as a sensor and operating at 100µT was used to measure changes that occurred in banana fruit during ripening. The longitudinal and transverse relaxation times (T1 and T2, respectively), were measured on fruit samples progressively drawn from a larger batch under storage. Physico-chemical attributes such as total soluble solids (TSS), titratable acidity (TA), pH, and color parameters were measured and used as reference measurements. Statistical analysis using cross-correlation, linear regression, analysis of variance (ANOVA), and principal components analysis (PCA) were performed to probe the relationships between various quality attributes. T1 showed high correlations with total soluble solids (R = 0.84), sugar:acid ratio (R = 0.84) and color parameters (R from 0.49 to 0.88). T2, on the other hand, was most highly correlated to pH (R = 0.76) but also had a statistically significant but negative correlation with Ri (-0.58 at p &lt;0.05). PCA results separated the first day from the remaining days of the ripening process and the overall variation was mostly explained by color attributes (a* and h), T1, TSS, and TSS/TA. During seven days of ripening in storage, the trend of change in the peel color of banana was best described by L*, a*, h and total color difference (TCD). The index of ripening, Ri, defined based on the apparent change in peel color was highly correlated to TSS, TSS/TA, L*, a*, h, TCD, and T1. The strong similarity between the evolution of T1 and the most commonly approved characteristics of banana ripening suggest that T1 has great potential for characterizing the ripening process of banana. However, an investigation of the full metabolic profile of banana during ripening would provide an understanding of the link between NMR relaxation and ripening characteristics. A distribution of T1 relaxation time of intact banana fruit at the micro-Tesla field was successfully generated using Laplace inversion. A suitable framework of T1-domain based studies on banana ripening also applicable to other fruit was discussed; it would provide a comprehensive understanding of structural changes and water mobility that occur in ripening banana. The SQUID-detected ultra-low field NMR used here shows promise as a tool for probing the quality of intact banana fruit. Keywords: Banana quality, Laplace inversion, Relaxometry, SQUID-NMR.

This thesis presents a theoretical approach to Ostwald ripening of droplets in arbitrary dimensions. A mean-field theory is constructed to incorporate screening effects among the competing droplets. The mean-field equations are solved to all orders in the volume fraction to provide analytic expressions for the coarsening rate, the droplet distribution function, and the time-dependent droplet number. These results are in agreement with experiments in three-dimension and with very large scale and extensive numerical studies in both two and three dimensions undertaken in this thesis. The numerical study also provides the time evolution of the structure factors, wherein lengths scale with the average droplet radius. Finally, the mean-field theory is extended to exciton systems and surfactant systems.

Thesis (MSc)--Stellenbosch University, 2002.
ENGLISH ABSTRACT: 'Forelle' is one of three blushed pear cultivars produced in South Africa. A mandatory minimum cold storage duration of 12 weeks at -0.5°C to ensure even ripening, prevents 'Forelle' from being marketed earlier. Since earlier marketing can result in premium prices (in excess of 50% morê per carton) research in recent years has been directed at reducing this 12 week cold storage period. Intermittent warming treatments, controlled atmosphere (CA) storage in combination with regular atmosphere (RA) storage intervals, and ethylene treatments, have been tested as alternatives to the 12 week cold requirement. However, none of these treatments delivered a better internal quality in terms of mealiness and astringency. Fruit harvested from the Warm Bokkeveld and Theewaterskloof areas at commercial maturity were stored at -0.5°C for up to 21 and 22 weeks, respectively, to understand the changes in ripening and mealiness of 'Forelle' pears after cold storage (Paper 1). Samples were removed every third weev, placed at 15°C, and maturity factors, total ACC concentration, ethylene production and respiration rates monitored every third day for 12 days. Fruit from the Warm Bokkeveld and the Theewaterskloof areas ripened after 6 and 7 weeks at -0.5°C, respectively. However, after 6 weeks of cold storage followed by 6 days at 15°C, all fruit harvested in the Warm Bokkeveld, and 70 % of the fruit harvested in the Theewaterskloof area, were mealy. With extended storage at -0.5°C (> 15 weeks) the incidence of mealiness declined in fruit from both areas, but never disappeared, when evaluated at 15°C over 12 days. Since harvest maturity affects the incidence of mealiness in other pear cultivars, the effect of harvest maturity on 'Forelle' pears with regard to mealiness development was examined (Paper 2). Fruit were harvested from the Ceres area, in weeks 8 (preoptimum), 10 (optimum), 12 and 14 (both post optimum). Maturity indices, juice content, mealiness, total ACC content, ethylene production and internal ethylene were monitored at harvest, after 6 weeks of storage at -0.5°C and again after 7 days at 15°C. Fruit harvested 2 weeks before commercial harvest (week 8) had the highest total ACC concentration, ethylene production and the potential to ripen, but also developed the highest incidence of mealiness (80%). However, fruit of all harvest maturities (except where contamination with 1-MCP occurred) were mealy. It would appear that factor(s), other than harvest maturity, play a more important role in the initiation of mealiness in 'Forelle' pears. Although ethylene has been shown to shorten the cold requirement of 'Forelle', there are conflicting reports as to its effectiveness in reducing mealiness. Consequently, the aim of the third paper was to evaluate the effect of ethylene on ripening and mealiness of 'Forelle' pears. Fruit harvested from the Elgin area at commercial maturity were stored for 3 weeks at -0.5°C, treated with ethylene (100 Jl L.L·l , 24h, 20°C) and held at 20°C for a further 2 days (without ethylene). Control fruit were held at 20°C for 3 days. Fruit were returned to -0.5°C for a further 3 weeks. After a subsequent 3 days at 20°C, flesh firmness was 4.6 kg in treated fruit compared to 6.1 kg for control fruit. At this point all fruit treated with ethylene were mealy. Control fruit all exhibited mealiness after a further 3 weeks at -0.5°C followed by 7 days at 15°C. Ethylene treatment advanced fruit maturity, but did not prevent or alleviate mealiness. Mealiness is a textural disorder recognized by a dry soft pulp. This has previously been recorded in 'd'Anjou' pears, as a result of storing the fruit for too long at -1.1°C, but has also been the result of a chilling injury in fruit like nectarines, kiwi and persimmon. The role of storage temperature on ripening, and specifically mealiness, of 'Forelle' was thus investigated (Paper 4). Fruit harvested from the Elgin area at commercial maturity were stored at -0.5°C, 4.0°C and 7.5°C for 0, 3 and 6 weeks. Samples were removed every third week, placed at 15°C, and maturity indices, extractable juice content, mealiness, total ACC content, internal ethylene concentration and ethylene production were monitored on removal and after 7 days. Flesh firmness of the 4°C stored fruit was 0.5 kg lower than fruit stored at -0.5°C, on removal from storage. Fruit stored at 4°C and 7.5°C ripened with little to no mealiness (0 and 8% respectively) in contrast to fruit stored at -0.5°C (70% mealy). Total ACC accumulation and ethylene production were higher for fruit stored at 4°C and 7.5°C than fruit stored at -0.5°C. Storage temperature appears to playa role in the development of mealiness. Although storage temperatures influenced mealiness development, this research should be repeated before this can recommended as a commercial treatment. The underlying mechanism of action in the development of mealiness should be investigated. By examining fruit grown in different climatical areas, harvested at different maturities, treated with exogenous ethylene and stored at different temperatures, this research has helped to a better understanding of the role of factors affecting ripening and development of mealiness in 'Forelle'.
AFRIKAANSE OPSOMMING: Forelle' is een van drie blos peer kultivars wat in Suid Afrika geproduseer word. 'n Minimum van 12 weke by -0.5°C opberging, is deur wetgewing vasgestel, om eweredige rypheid van 'Forelle' te verseker. Vroeër bemarking van 'Forelle' kan daartoe lei dat vrugte premium pryse, van 50% meer per karton behaal. Aangesien die vasgestelde koue periode verhoed dat 'Forelle' vroeër bemark kan word, het onlangse navorsing gefokus op vermindering van die vasgestelde opberging van 12 weke by -0.5°C. Afwisselende verwarmmgs behandelings gedurende koue opberging, beheerde atmosfeer (BA) opberging in kombinasie met gewone atmosfeer (GA) opbergings intervalle, en etileen behandelings, is _getoets as alternatiewe vir die 12 weke opbergings vereiste by -0.5°C. Geen van die bogenoemde behandelings kon egter 'n beter interne kwaliteit in terme van meleringheid en frankheid as 'n alternatief verseker nie. Die doel van die eerste proef was om die invloed van koue opberging by -0.5°C op rypwording en melerigheid van 'Forelle' te bepaal. Vrugte is in die Warm Bokkeveld and Theewaterskloof areas geoes tydens kommersiële oesrypheid, waarna hulle vir 21 en 22 weke, respektiewelik, by -0.5°C opgeberg is. Monsters is elke derde week vanaf die -0.5°C koue opberging geneem en by 15°C geplaas, waarna rypheids indeksering, totale ACC konsentrasie, etileen produksie and respirasie tempos elke derde dag vir 12 dae gemonitor is. Vrugte wat in dieWarm Bokkeveld en Theewaterskloof areas geoes is, het rypgeword by 15°C, na 6 and 7 weke by -0.5°C, respektiewelik. Alle vrugte vanaf die Warm Bokkeveld en 70% vrugte vanaf die Theewaterskloof area, het egter na die 6 en 7 weke by -0.5°C, respektiewelik, en 6 dae by 15°C, melerigheid ontwikkel. Vrugte wat vir langer as 15 weke by -0.5°C opgeberg is, het in albei areas 'n afname in melerigheid getoon, maar die defek het nooit heeltemal verdwyn tydens evaluasie by 15°C nie. Oes rypheid affekteer die ontwikkeling van melerigheid in ander peer kultivars. Die tweede proef was dus gefokus op dip. invloed van oes rypheid op 'Forelle' se ontwikkeling van melerigheid. Vrugte is in die Warm Bokkeveld area geoes in week 8 (pre-optimum), 10 (optimum), 12 and 14 (albei post-optimum). Rypheids indekse, uitdrukbare sapinhoud, meleringheid, totale ACC konsentrasie, interne etileen vlakke en etileen produksie is gemonitor, na opberging vir 6 weke by -0.5°C en 7 dae by 15°C. Vrugte wat 2 weke voor kommersiële rypheid geoes is (week 8) het die hoogste totale ACC konsentrasie en etileen produksie gehad, en het reeds die potensiaal gehad om ryp te word. Die hoogste vlakke van melerigheid (80%) is ook in vrugte wat tydens hierdie oes verkry is, waargeneem. Vrugte wat op alle tye geoes is, het melerigheid ontwikkel, behalwe waar kontaminasie met 1-MCP plaasgevind het. Dit wil voorkom asof 'n ander faktor 'n belangriker rol in die ontwikkeling van melerigheid in 'Forelle' speel as oes rypheid. Etileen is bewys om die vereiste koue opberging vir 'Forelle' te kan verkort, maar daar is konflik oor die effektiwiteit van etileen op die verlaging van melerigheid in 'Forelle'. Die doel van die derde proef was dus om die effek van eksterne etileen behandeling op rypheid en melerigheid van 'Forelle' te toets. Vrugte wat in die Elgin area by kommersiële oesrypheid geoes is, is vir 3 weke gestoor by -0.5°C, met etileen behandel (100 Il L.L-1, 24h, 20°C) en vir 'n verdere 2 dae by 20°C gehou (sonder etileen). Kontrole vrugte is vir 3 dae by 20°C gehou. Daarna is vrugte weer vir 'n verdere 3 weke by -0.5°C opgeberg. Na 'n verdere 3 dae by 20°C, was vlees fermheid van etileen behandelde vrugte 4.6 kg .n vergelyking met 6.1 kg vir die kontrole vrugte. Alle vrugte wat met etileen behandel is, was melerig op hierdie stadium. Die kontrole vrugte het ook almal melerig geword, maar slegs na 'n verdere 3 weke by -0.5°C en 7 dae by 15°C. Etileen behandeling het dus die rypheid van 'Forelle' bevorder, maar het nie melerigheid voorkom nie. Melerigheid is 'n tekstuur probleem, wat gekenmerk word aan sagte droë pulp. Hierdie tekstuur probleem is voorheen waargeneem in 'd'Anjou' pere wat te lank by -Ll=C opgeberg is, maar is ook kenmerkend by vrugte soos nektariens, kiwi en persimmon wat aan koue skade ly. Lie gevolg is dat die effek van opbergings temperatuur op 'Forelle' rypwording en melerigheid getoets moes word. Vrugte is geoes van die Elgin area tydens kommersiële oesrypheid en gestoor by -0.5°C, 4.0°C en 7.5°C vir 0, 3 en 6 weke. Vrug monsters is geneem, na verwydering van bogenoemde stoor temperature en na 7 dae by 15°C, waarby rypheids indekse, uitdrukbare sapinhoud, meleringheid, totale ACC konsentrasie, interne etileen vlakke en etileen produksie gemonitor is. Vlees fermheid van vrugte wat vir 6 weke by 4°C opgeberg was, was 0.5 kg laer as vrugte wat by -0.5°C opgeberg was. Vrugte wat by 4°C and 7.5°C vir 6 weke gestoor is en by 15°C ryp geword het, het min tot geen melerigheid ontwikkel (0 and 8%, respektiewelik) nie. Vrugte wat by -0.5°C opgeberg was het egter hoë vlakke van melerigheid bereik (70% melerig). Totale ACC akkumulasie en etileen produksie was hoër vir vrugte wat by 4°C en 7.5°C gestoor was, teenoor vrugte wat gestoor was by -0.5°C. Dit wil voorkom asof na-oes opbergings temperature wel 'n rol speel in die ontwikkeling van melerigheid. Alhoewel dit voorkom asof na-oes temperature wel 'n rol speel in die ontwikkeling van melerigheid in 'Forelle' pere, is meer basiese navorsing nodig om die meganisme van werking in melerigheid ontwikkeling te verstaan. Na-oes temperatuur as 'n faktor wat melerigheid kan beïnvloed, moet oor 'n reeks van seisoene nagevors word. Laasgenoemde is van uiterste belang aangesien die invloed van seisoenale variasies op melerigheid nog nie gekwantifiseer is nie. Die navorsing was gefokus daarop om vas te stel watter faktore 'n fisiologiese rol speel in rypwording en melerigheid van 'Forelle' pere. Deurdat vrugte van twee areas met verskillende klimate, vrugte met verskye oesryphede, ekterne etileen behandeling, en vrugte van verskillende opbergings temperature ondersoek is, het hierdie navorsing gehelp om 'n beter begrip te vorm van die rol van hierdie faktore op die rypwording en die ontwikkeling van melerigheid in 'Forelle'.

Various techniques for accelerating mature flavour development in Cheddar cheese were compared. Control cheese ( c) was manufactured by using Streptococcus cremor is AM2, a starter used in normal commercial manufacture. A combination of S. cremoris AM2 and Streptococcus lactis C2 Lac- Prt- mutant was used in the manufacture of test cheeses (M). §._. lactis C2 mutant was grown in glucose broth at 30°c and pH 6 .O for 16 hours, followed by concentration and diafiltration to 1011cfu mL - 1 using microfiltration equipment. The control cheesemilk was inoculated to 6x107 streptococci pe mL with S. cremoris AM2 and the mutant vat cheesemilk to 2x109 per mL with a combination of ~ cremoris AM2 and ~ lactis C2 mutant. The starter population in cheese containing mutant starter was 100 times that in control cheese (1010 compared to 10a). Cheeses were also made with added bacterial neutral proteinase (Neutrase, N) and stored at a0c (a) and 15°c ( 15) for 32 weeks. This resulted in cheese being subjected to the following treatments: ca (control), C15, CNa, CN15, Ma·, M15, MNa, and MN15. Cheddaring times were slightly reduced and milling acidities slightly higher in the vat . containing mutant starter. However the composition of all cheese was satisfactory. Bacteriological counts, proteolysis, rheological properties and flavour development of these cheeses were monitored at regular intervals throughout maturation. The order of the effectiveness of the treatment in accelerating ripening was MN15, >M15,> CN15,> C15,> MNa,> Ma,> CNa,> ca. Cheeses from these treatments attained the characteristics of control cheese stored at a0 c (Ca) for 6 months after 1.4, 1.7, 2.0, 2.6, 2.8, 3.2, 4.3 and 6.0 months respectively. Cheese quality was not adversely affected except for bitterness in CN8 cheese and overmaturity in CN15 cheese late in the storage period. The possible mechanisms and relative merits of the various treatments are discussed with special reference to an "active role" theory of starter bacteria in flavour development.

Tomatoes are the fourth most valuable commodity in agriculture after rice, wheat and soybeans globally with 151 million tonnes of fruit being produced in 2012. The tomato fruit is also a model system for fleshy fruit development. During ethylene-regulated fruit ripening there are complex changes in fruit chemical composition due to degradation and synthesis of a number of soluble and volatile metabolites. Ultimately, these changes control the composition of the ripe fruit and dictate its flavour and texture. It is known that ripening can proceed when mature green fruit are removed from the plant (and indeed this is standard commercial practice) but the extent to which metabolic changes are sustained when fruit are ripened in this way has yet to be established. A modelling approach such as constraints-based modelling can provide system-level insights into the workings of the complex tomato metabolic network during ripening. The first aim of this thesis was therefore to construct a genome-scale metabolic network model for tomato and to use this model to explore metabolic network flux distributions during the transitions between the stages of fruit ripening. The flux distributions predicted provided insight into the production and usage of energy and reductants, into routes for climacteric CO₂ release, and the metabolic routes underlying metabolite conversions during ripening. The second aim of this thesis was to use the model to explore metabolic engineering strategies for increased production of lycopene in tomato fruit. The model predictions showed that rearrangement of dominant metabolic fluxes were required to cope with the increased demand for reductants at high lycopene accumulation, which came at a cost of a lower accumulation of other secondary metabolites. Overall the thesis provides an approach to connect underlying metabolic mechanisms to the known metabolic processes that happen during ripening.

A cell culture system was developed to study the production of prostaglandins by cervical cells from late pregnant guinea pigs. This permitted the examination of the influence of various substances on the synthesis of the prostaglandins, including progesterone and the anti-progesterone drug RU486 (Mifepristone/RU38486). RU486 has been found to promote cervical ripening in humans and guinea pigs. It is thought to increase the sensitivity of the uterus to prostaglandins and thereby promote muscle activity. It is licensed in the United Kingdom as an abortifacient. Since this antiprogestin can provoke cervical ripening alone an accessible source of tissue from an animal with a similar physiology to the human seemed to be an appropriate starting point from which to investigate the effects of this steroidal derivative and how it may affect prostaglandin production. The results show that prostaglandin output can be provoked in vitro by agents such as lipopolysaccharide and phorbol ester. The observed effects by RU486 were mixed. Giving the animals examined, there were, however, some instances where a significant increase was detected, apparently associated with the calcium ionophore A23187, and others where there appeared to be a reduction. The inclusion of RU486 in the culture medium with other treatments did not produce any significant differences compared to the treatment on its own, and alone RU486 only produced a significant difference where the animal had been given the drug in vivo.

Mango fruit ripen quickly. It is highly perishable. Short shelf life of mango fruit limits its transportation to distant domestic and international markets. The objective of my research was to elucidate the role of changes in endogenous levels of brassinosteroids (BRs), ethylene, abscisic acid (ABA) and/or indole-3-acetic acid (IAA) in modulating the ripening processes of 'Kensington Pride' mango fruit. The endogenous levels of these regulators were regulated using inhibitors of their biosynthesis and/or action to unfold their mechanism in delaying/hastening mango fruit ripening, extending storage life and improving fruit quality as well as to underpin the mode of action of ABA and NO in modulating ethylene biosynthesis and activities of fruit softening enzymes in the pulp during ripening and/or alleviating chilling injury (CI) during cool storage.Higher endogenous level of ABA at the climacteric-rise stage triggered the climacteric peak of ethylene production coupled with a significant quadratic relationship between both of them; suggest that ABA play a key role in modulating mango fruit ripening. The exogenous application of ABA (1.0 - 2.0 mM) promoted skin colour development and fruit softening during ripening, and the trend was reversed with its inhibitor of biosynthesis - nordihydroguaiaretic acid (0.1 - 0.2 mM NDGA). The endogenous level of IAA was higher at the initial stage of ripening and decline over ripening period. The exogenous application of 45 - 60 ng g-1 FW Epi- BL increased the climacteric peak of ethylene and respiration, promoted skin colour, but the changes in the endogenous level of BRs (castasterone and brassinolide) are unlikely to modulate mango fruit ripening as it is present in a trace amounts in mango pulp tissues throughout the ripening period.Exogenous postharvest application of ABA (1.0 mM) increased the climacteric peak of ethylene production through promoting the activities of 1- aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS), ACC oxidase (ACO) enzymes, and ACC content, decreased the fruit firmness with increased exopolygalacturonase (exo-PG), endo-PG and endo-1,4-_-D-glucanase (EGase) activities, decreased pectinesterase (PE) activity in the pulp, higher total sugars and sucrose, advanced degradation of total organic acids, citric and fumaric acid. The application of 0.2 mM NDGA showed reverse trends for these ripening indicator parameters.NO fumigation (20 μL L-1 or 40 μL L-1) was more effective in delaying fruit ripening when applied at the pre-climacteric (PC) stage, than at the climacteric-rise (CR) stage. NO (20 μL L-1) fumigation delayed and suppressed the endogenous ethylene production, activities of ACS and ACO enzymes, and ACC content, rate of respiration, higher pulp rheological properties (firmness, springiness, cohesiveness, chewiness, adhesiveness, and stiffness) with lower activities of exo-, endo-PG, EGase, but maintained higher PE activity in pulp tissues during ripening at 21°C and cool storage (13°C). NO treatments (20 and 40 μL L-1) significantly alleviated CI index during ripening at ambient temperature following 2- or 4-week of cold-stored (5°C) period. All NO fumigation treatments significantly suppressed ethylene production and respiration rates irrespective of cold storage period. NO–fumigated with above 5 μL L-1 significantly delayed fruit softening up to 2 days and retarded colour development, reduced total sugar and fructose concentrations, increased tartaric and shikimic acid at fully ripe stage during ripening period irrespective of cold-stored fruit.In conclusion, the higher levels of endogenous IAA in fruit pulp during the PC stage and the accumulation of ABA prior to the climacteric stage might switch on ethylene production that triggers fruit ripening. There is a significant quadratic relationship between endogenous level of ABA in the pulp and ethylene production during fruit ripening period. Exogenous Epi-BL promoted fruit ripening, whilst, the changes in endogenous levels of BRs are unlikely to modulate mango fruit ripening. Moreover, the exogenous application of ABA (1.0 mM) promoted the activities of ethylene biosynthesis enzymes (ACS and ACO) and ACC content and ethylene biosynthesis as well as endo-PG activity in the pulp, whilst, the NDGA-treated fruit showed the reverse trends. The application of NO fumigation (20 L L-1) at PC stage can be effectively used to delay the fruit ripening up to 2 days at ambient temperature (21°C) and cool-storage (13°C) through suppression the activity of ethylene biosynthesis and softening enzymes and alleviate CI following 2- and 4-week cold storage (5°C) without any adverse effects on fruit quality.

The ripening stage of apple fruits at harvest is the main factor influencing fruit quality during the cold storage period that lasts several months and give rise to physiological disorders in fruits of susceptible cultivars. In particular, superficial scald is connected to α-farnesene oxidation, leading to fruit browning. Therefore, the assessment of the optimal ripening stage at harvest is considered to be crucial to control the overall quality, the length of storage life and the scald incidence. However, the maturity indexes traditionally used in the horticultural practice do not strictly correlate with fruit maturity, and do not account for the variability occurring in the field. Hence, the present work focused on the determination of apple fruit ripening with the use of an innovative, non-destructive device, the DA-meter. The study was conducted on ‘Granny Smith’ and ‘Pink Lady’ cultivars, which differ in scald susceptibility. Pre- and post- harvest ripening behavior of the fruits was studied, and the influence of ripening stage and treatments with 1-MCP were evaluated in relation to scald development and related metabolites. IAD was shown to be a reliable indicator of apple ripening, allowing cultivar-specific predictions of the optimal harvest time in different growing seasons. IAD may also be employed to segregate apple fruits in maturity classes, requiring different storage conditions to control flesh firmness reduction and scald incidence. Moreover, 1-MCP application is extremely effective in reducing superficial scald, and its effect is influenced by fruit ripening stage reached at harvest. However, the relation between ethylene and α-farnesene was not entirely elucidated. Thus, ethylene can be involved in other oxidative processes associated with scald besides α-farnesene regulation.

Objectives. To assess the comparative effectiveness and potential harms of cervical ripening in the outpatient setting (vs. inpatient, vs. other outpatient intervention) and of fetal surveillance when a prostaglandin is used for cervical ripening. Data sources. Electronic databases (Ovid® MEDLINE®, Embase®, CINAHL®, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews) to July 2020; reference lists; and a Federal Register notice. Review methods. Using predefined criteria and dual review, we selected randomized controlled trials (RCTs) and cohort studies of cervical ripening comparing prostaglandins and mechanical methods in outpatient versus inpatient settings; one outpatient method versus another (including placebo or expectant management); and different methods/protocols for fetal surveillance in cervical ripening using prostaglandins. When data from similar study designs, populations, and outcomes were available, random effects using profile likelihood meta-analyses were conducted. Inconsistency (using I2) and small sample size bias (publication bias, if ≥10 studies) were assessed. Strength of evidence (SOE) was assessed. All review methods followed Agency for Healthcare Research and Quality Evidence-based Practice Center methods guidance. Results. We included 30 RCTs and 10 cohort studies (73% fair quality) involving 9,618 women. The evidence is most applicable to women aged 25 to 30 years with singleton, vertex presentation and low-risk pregnancies. No studies on fetal surveillance were found. The frequency of cesarean delivery (2 RCTs, 4 cohort studies) or suspected neonatal sepsis (2 RCTs) was not significantly different using outpatient versus inpatient dinoprostone for cervical ripening (SOE: low). In comparisons of outpatient versus inpatient single-balloon catheters (3 RCTs, 2 cohort studies), differences between groups on cesarean delivery, birth trauma (e.g., cephalohematoma), and uterine infection were small and not statistically significant (SOE: low), and while shoulder dystocia occurred less frequently in the outpatient group (1 RCT; 3% vs. 11%), the difference was not statistically significant (SOE: low). In comparing outpatient catheters and inpatient dinoprostone (1 double-balloon and 1 single-balloon RCT), the difference between groups for both cesarean delivery and postpartum hemorrhage was small and not statistically significant (SOE: low). Evidence on other outcomes in these comparisons and for misoprostol, double-balloon catheters, and hygroscopic dilators was insufficient to draw conclusions. In head to head comparisons in the outpatient setting, the frequency of cesarean delivery was not significantly different between 2.5 mg and 5 mg dinoprostone gel, or latex and silicone single-balloon catheters (1 RCT each, SOE: low). Differences between prostaglandins and placebo for cervical ripening were small and not significantly different for cesarean delivery (12 RCTs), shoulder dystocia (3 RCTs), or uterine infection (7 RCTs) (SOE: low). These findings did not change according to the specific prostaglandin, route of administration, study quality, or gestational age. Small, nonsignificant differences in the frequency of cesarean delivery (6 RCTs) and uterine infection (3 RCTs) were also found between dinoprostone and either membrane sweeping or expectant management (SOE: low). These findings did not change according to the specific prostaglandin or study quality. Evidence on other comparisons (e.g., single-balloon catheter vs. dinoprostone) or other outcomes was insufficient. For all comparisons, there was insufficient evidence on other important outcomes such as perinatal mortality and time from admission to vaginal birth. Limitations of the evidence include the quantity, quality, and sample sizes of trials for specific interventions, particularly rare harm outcomes. Conclusions. In women with low-risk pregnancies, the risk of cesarean delivery and fetal, neonatal, or maternal harms using either dinoprostone or single-balloon catheters was not significantly different for cervical ripening in the outpatient versus inpatient setting, and similar when compared with placebo, expectant management, or membrane sweeping in the outpatient setting. This evidence is low strength, and future studies are needed to confirm these findings.

We had proposed to look at several aspects of auxin metabolism in fruit tissues: 1) IAA biosynthesis from tryptophan and IAA biosynthesis via the non-tryptophan pathway; 2) changes in the capacity to form conjugates and catabolites of auxin at different times during fruit development and; 3) the effects of modifying auxin metabolism in fruit tissues. The latter work focused primarily on the maize iaglu gene, with initial studies also using a bacterial gene for hydrolysis of IAA-aspartate. These metabolic and molecular studies were necessary to define potential benefits of auxin metabolism modification and will direct future efforts for crop improvement by genetic methods. An in vitro system was developed for the production of tomato fruit in culture starting from immature flowers in order to ascertain the effect of auxin modification on fruit ripening. IAA supplied to the fruit culture media prior to breaker stage resulted in an increase in the time period between breaker and red-ripe stages from 7 days without additional IAA to 12 days when 10-5 M IAA was added. These results suggest that significant changes in the ripening period could be obtained by alteration of auxin relationships in tomato fruit. We generated transgenic tomato plants that express either the maize iaglu gene or reduced levels of the gene that encodes the enzyme IAA-glucose synthetase. A modified shuttle vector pBI 121 expressing the maize iaglu gene in both sense and antisense orientations under a 35S promoter was used for the study. The sense plants showed total lack of root initiation and development. The antisense transgenic plants, on the other hand, had unusually well developed root systems at early stages in development. Analysis showed that the amount and activity of the endogenous 75 kDa IAGLU protein was reduced in these plants and consequently these plants had reduced levels of IAA-glucose and lower overall esterified IAA.

Background : Banana being a monocot and having distinct peel and pulp tissues is unique among the fleshy fruits and hence can provide a more comprehensive understanding of fruit ripening. Our previous research which translated ripening discoveries from tomato, led to the identification of six banana fruit-associated MADS-box genes, and we confirmed the positive role of MaMADS1/2 in banana ripening. The overall goal was to further elucidate the banana ripening signaling pathway as mediated by MADS-boxtranscriptional regulators. Specific objectives were: 1) characterize transcriptional profiles and quality of MaMADS1/2 repressed fruit; 2) reveal the role of additional MaMADSgenes in ripening; 3) develop a model of fruit MaMADS-box mode of action; and 4) isolate new components of the banana ripening signaling pathway. Major conclusion: The functions of the banana MaMADS1-5 have been examined by complimenting the rinor the TAGL1-suppressed lines of tomato. Only MaMADS5 exhibited partial complementation of TAGL1-suppressed and rinlines, suggesting that while similar genes play corresponding roles in ripening, evolutionary divergence makes heterologous complementation studies challenging. Nevertheless, the partial complementation of tomato TAGL1-surpessed and rinlines with MaMADS5 suggests this gene is likely an important ripening regulator in banana, worthy of further study. RNA-seqtranscriptome analysis during ripening was performed on WT and MaMADS2-suppressed lines revealing additional candidate genes contributing to ripening control mechanisms. In summary, we discovered 39 MaMADS-box genes in addition to homologues of CNR, NOR and HB-1 expressed in banana fruits, and which were shown in tomato to play necessary roles in ripening. For most of these genes the expression in peel and pulp was similar. However, a number of key genes were differentially expressed between these tissues indicating that the regulatory components which are active in peel and pulp include both common and tissue-specific regulatory systems, a distinction as compared to the more uniform tomato fruit pericarp. Because plant hormones are well documented to affect fruit ripening, the expressions of genes within the auxin, gibberellin, abscisic acid, jasmonic acid, salicylic and ethylene signal transduction and synthesis pathways were targeted in our transcriptome analysis. Genes’ expression associated with these pathways generally declined during normal ripening in both peel and pulp, excluding cytokinin and ethylene, and this decline was delayed in MaMADS2-suppressed banana lines. Hence, we suggest that normal MaMADS2 activity promotes the observed downward expression within these non-ethylene pathways (especially in the pulp), thus enabling ripening progression. In contrast, the expressions of ACSand ACOof the ethylene biosynthesis pathway increase in peel and pulp during ripening and are delayed/inhibited in the transgenic bananas, explaining the reduced ethylene production of MaMADS2-suppressed lines. Inferred by the different genes’ expression in peel and pulp of the gibberellins, salicylic acid and cytokinins pathways, it is suggested that hormonal regulation in these tissues is diverse. These results provide important insights into possible avenues of ripening control in the diverse fruit tissues of banana which was not previously revealed in other ripening systems. As such, our transcriptome analysis of WT and ripening delayed banana mutants provides a starting point for further characterization of ripening. In this study we also developed novel evidence that the cytoskeleton may have a positive role in ripening as components of this pathway were down-regulated by MaMADS2 suppression. The mode of cytoskeleton involvement in fruit ripening remains unclear but presents a novel new frontier in ripening investigations. In summary, this project yielded functional understanding of the role and mode of action of MaMADS2 during ripening, pointing to both induction of ethylene and suppression of non-ethylene hormonal singling pathways. Furthermore, our data suggest important roles for cytoskeleton components and MaMADS5 in the overall banana ripening control network. Implications: The project revealed new molecular components/genes involved in banana ripening and refines our understanding of ripening responses in the peel and pulp tissues of this important species. This information is novel as compared to that derived from the more uniform carpel tissues of other highly studied ripening systems including tomato and grape. The work provides specific target genes for potential modification through genetic engineering or for exploration of useful genetic diversity in traditional breeding. The results from the project might point toward improved methods or new treatments to improve banana fruit storage and quality.

Our study was designed to elucidate the chemical determinants of pectin cross-linking in developing fruits of apple and peach and to evaluate the role of breakage cross-linkages in swelling, softening, and cell separation during the ripening. Peaches cell walls soften and swell considerably during the ripening, whereas apples fruit cells maintain wall firmness but cells separate during late stages of ripening. We used a "double-reduction" technique to show that levels of non-methyl esters of polyuronic acid molecules were constant during the development and ripening and decreased only in overripe fruit. In peach, methyl and non-methyl esters increased during the development and decreased markedly during the ripening. Non-methyl ester linkages in both fruit decreased accompanied fruit softening. The identity of the second component of the linkage and its definitive role in the fruit softening remain elusive. In preliminary examination of isolated apples cell walls, we found that phenolic compounds accumulate early in wall development but decrease markedly during ripening. Quantitative texture analysis was used to correlate with changes to wall chemistry from the fresh-picked ripe stage to the stage during storage when the cell separation occurs. Cell wall composition is similar in all cultivars, with arabinose as the principal neutral sugar. Extensive de-branching of these highly branched arabinans pre-stages softening and cell-cell separation during over-ripening of apple. The longer 5-arabinans remain attached to the major pectic polymer rhamnogalacturonan I (RG I) backbone. The degree of RG I branching, as judged from the ratios of 2-Rha:2,4-Rha, also decreases, specially after an extensive arabinan de-branching. Loss of the 4-Rham linkages correlated strongly with the softening of the fruit. Loss of the monomer or polymer linked to the RG I produce directly or indirectly the softening of the fruit. This result will help to understand the fruit softening and to have better control of the textural changes in fruit during the ripening and especially during the storage. 'Wooliness', an undesirable mealy texture that is induced during chilling of some peach cultivars, greatly reduces the fruit storage possibilities. In order to examine the hypothesis that the basis for this disorder is related to abnormality in the cell wall softening process we have carried out a comparative analysis using the resistant cultivar, Sunsnow, and a sensitive one, Hermosa. We investigated the activity of several pectin- and glycan-modifying enzymes and the expression of their genes during ripening, chilling, and subsequent shelf-life. The changes in carbohydrate status and in methyl vs. non-methyl uronate ester levels in the walls of these cultivars were examined as well to provide a basis for comparison of the relevant gene expression that may impact appearance of the wooly character. The activities of the specific polygalacturonase (PGase) and a CMC-cellulase activities are significantly elevated in walls of peaches that have become wooly. Cellulase activities correlated well with increased level of the transcript, but differential expression of PGase did not correspond with the observed pattern of mRNA accumulation. When expression of ethylene biosynthesis related genes was followed no significant differences in ACC synthase gene expression was observed in the wooly fruit while the normal activation of the ACC oxidase was partially repressed in the Hermosa wooly fruits. Normal ripening-related loss of the uronic acid-rich polymers was stalled in the wooly Hermosa inconsistent with the observed elevation in a specific PGase activity but consistent with PG gene expression. In general, analysis of the level of total esterification, degree of methyl esterification and level of non-methyl esters did not reveal any major alterations between the different fruit varieties or between normal and abnormal ripening. Some decrease in the level of uronic acids methyl esterification was observed for both Hermosa and Sunsnow undergoing ripening following storage at low temperature but not in fruits ripening after harvest. Our results support a role for imbalanced cell wall degradation as a basis for the chilling disorder. While these results do not support a role for the imbalance between PG and pectin methyl esterase (PME) activities as the basis for the disorder they suggest a possible role for imbalance between cellulose and other cell wall polymer degradation during the softening process.