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1
Xu, Yue. "Isolation and characterization of components from whey /". View thesis, 1996. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030808.133723/index.html.
Testo completo
2
Mohr, Jan-Christian. "Optimized utilization of quarg production residuals". Thesis, University of South Wales, 2011. https://pure.southwales.ac.uk/en/studentthesis/optimized-utilization-of-quarg-production-residuals(6a7a4f48-5aa2-40b4-a100-ad7daa8d1a59).html.
Testo completoAbstract (sommario):
Acid whey is a by-product of the quarg production and arises in large volumes in dairies. A considerable disposal problem arises due to the lack of obtainable proceeds from acid whey utilisation. Additionally, sustainable and energy efficient treatment methods for high strength liquid wastes from dairies cleaning operation are needed to reduce the costs of wastewater treatment. Samples of acid whey and spent cleaning solutions from a quarg cheese production plant were collected. The composition and physical properties were analysed and evaluated against waste treatment process requirements. The occurrence of different waste streams, their volumes and frequencies were also investigated. A laboratory scale membrane nanofiltration plant was designed, and built for investigation of the volume reduction of cleaning process effluents with emphasis to treatment options for the filtration concentrates. The examination of the rheological properties of alkaline CIP wastewaters at different volume reduction ratios clearly shows that these effluents are Newtonian fluids even at high concentrations. The anaerobic biodegradability of acid whey and mixtures containing portions of alkaline CIP wastewaters at different volume reduction ratios was tested. Characteristic process kinetics for acid whey fermentation in batch mode was observed. The occurrence of a second lag-phase in mixtures containing larger portions of acid whey was identified as phase separation- due to rapid acidification of lactose. Anaerobic digestion (AD) was identified as a suitable treatment option for acid whey and alkaline CIP wastewaters. Four anaerobic digester types were designed with regard to their suitability for high strength waste treatment and were built and operated at laboratory scale. The reactors tested were: a) A Continuous Stirred Tank Reactor (CSTR); b) An Anaerobic Membrane Reactor (AMR); c) An Upflow Anaerobic Sludge Blanket (UASB) re- actor; and d) A novel two-stage process design consisting of a combined acidification and crystallization stage and a gaslift driven fluidised bed methanogenic stage. The operation of the AMR process and also of the UASB process with internal circulation and pH-control using alkaline CIP effluents was evaluated at high loading rates of 7.7 g•L-1•d-1 and 10.2 g•L-1•d-1 respective. However, in the experiments it was demonstrated that even with perfect biomass retention the operation of one stage anaerobic digestion at high loading rates caused process upsets. Precipitation and accumulation of milk minerals within the sludge was observed in all one stage experiments. The conclusions drawn from one stage studies led to the design of a novel high-rate diges- tion system to meet the demands of anaerobic digestion of acid whey and effluents from dairy plant cleaning. The design based on different high-rate industrial reactor designs and incorporate the ideas of staging, crystallisation of calcium salts prior to anaerobic di- gestion, fluidised bed and internal circulation reactors, and also jet-loop or gaslift reactors. The performance of the novel system when treating acid whey is comparable to the results of well designed, two-stage digesters treating cheese whey which is easier to digest.
3
Dlamini, Abednego Mfanufikile. "Microbial biopolymers from whey : production and applications /". View thesis View thesis, 1997. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030514.130601/index.html.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Western Sydney, Hawkesbury."A thesis submitted to the University of Western Sydney Hawkesbury in fulfillment of the requirement for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 204-224).
4
Pan, Mei-Rong. "High quality fat replacers from whey proteins /". free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9998501.
Testo completo
5
Xu, Yue. "Isolation and characterization of components from whey". Thesis, View thesis, 1996. http://handle.uws.edu.au:8081/1959.7/248.
Testo completoAbstract (sommario):
The structure, functionality, isolation methods and applications of whey components, particularly the proteins and lactose, have been extensively studied. These studies have had a great impact on the food industry where whey components are increasingly being used as food ingredients. Two generations of whey protein product, namely Lactalbumin, produced by heat-induced precipitation, and Whey Protein Concentration/ Isloate, produced by ultrafiltration/ ion exchange chromatography, have been commercialised. Crystalline lactose in the food and pharmaceutical grades is also being produced. Recently, research activities in whey fractionation have shifted to the isolation of the minor components. This thesis is aimed at developing a Total Whey Utilization strategy by which the several components of the whey stream would be completely recovered by fractionation, resulting in little or no residue to be disposed of in the wastewater stream. Therefore, this study was initially dedicated to the development of novel separation methods which would be suitable for the Total Whey Utilization process. The development of those techniques revealed some previously unknown feature of whey components. The mechanisms of the separation methods have been also investigated. Although crystallization is an efficient method for fractionation or purification, its disadvantage is that the mother liquor is a wastewater containing high salt and BOD (Biological Oxygen Demand). The chromatographic method has been investigated in this work to separate the mother liquor or permeate into lactose and mineral fractions such that a goal of this thesis, namely a 'clean' water stream after processing whey, can be finally achieved. These studies have focused on the effect of resin type, salt form of the resin and the operating conditions on the separation of the lactose and mineral fraction.
6
Kisaalita, William Ssempa. "Anaerobic fermentation of whey : acidogenesis". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27362.
Testo completoAbstract (sommario):
Based on the initial exploratory results of single-phase (acidogenesis and methanogenesis takes place in one vessel) whey biomethanation studies, a two-phase (acidogenesis and methanogenesis takes place in two separated serial vessels) biomethanation process was found to be more suitable for dealing with the current whey utilisation and/or disposal problem. Acidogenesis was found to be less understood in comparison to methanogenesis and therefore acidogenesis became the central problem of this thesis.
Given that 90% of the five-day biochemical oxygen demand in whey is
due to lactose, continuous culture (Chemostat) experiments were undertaken
to examine the general mechanism of lactose acidogenesis by a mixed
undefined culture using ¹⁴C-labeled tracers. Also the influence of whey protein (mainly β-lactoglobulin) on the general fermentation scheme was addressed. Experimental factors included a pH range of 4.0 to 6.5, a mesophilic temperature of 35°C and a dilution rate (D) range of 0.05 to 0.65 h⁻¹.
At a fixed pH level, the observed variability in the main acidogenic
end products (acetate, propionate, butyrate and lactate) with respect to D
were found to be a consequence of the systematic separation of the various
microbial groups involved in acidogenesis. Batch incubation of a [¹⁴C(U)]-lactate tracer with chemostat effluent samples and preparative separation of the end products followed by a liquid scintillation assay of the location of the radio activity demonstrated that a microbial population lactate to other end products and hence the observed increase in lactate
concentrations at high D values.
Further use of [¹⁴C(U)]-butyrate and [¹⁴C(2)]-propionate revealed the
predominant carbon flow routes from pyruvate to the various end products. A
qualitative lactose acidogenic fermentation model was proposed, in which
lactose is converted to pyruvate via the Embden-Meyerhof-Parnas pathway.
Pyruvate in a parallel reaction is then converted to lactate and butyrate.
In the presence of hydrogen reducing methanogens lactate is converted to
acetate in a very fast reaction and not propionate as previously believed-.
The implications of these findings with regard to optimising the acidogenic
phase reactor are discussed.
Acidogenic fermentation of protein together with lactose did not affect
the carbon flow scheme. In the D range of 0.05 to 0.15 h⁻¹ low pH (pH <
5.0) was found to favour the butyrate route at the expense of the lactate
route and at high pH (pH > 5.5) the lactate route was favoured at the
expense of the butyrate route, the pH region of 5.0 to 5.5 being the
transition range.
In order to describe the microbial growth, the Monod chemostat model was chosen among the various alternatives, because of its simplicity and its physico-chemical basis. The estimated model parameters are reported.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
7
Landge, Virendra Laxman. "Quality of yogurt supplemented with whey protein concentrate and effects of whey protein denaturation". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2303.
Testo completo
8
Alomirah, Husam Fahd. "Separation and structural characterization of alpha-lactalbumin and beta-lactoglobulin from whey products". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38143.
Testo completoAbstract (sommario):
In most food applications, whey proteins are used, rather than the individual proteins and this accounts for the high functional variability among commercially available whey protein products, and limits their applications. The overall objective of this study was to investigate the structural and thermal properties of individual alpha-lactalbumin (alpha-Lac) and beta-lactoglobulin (beta-Lg) fractions isolated from different whey protein sources.A common non-chromatographic process that isolate alpha-Lac and beta-Lg, with relatively high purity and yield from liquid whey (LW), whey protein concentrate (WPC) and whey protein isolate (WPI) using different chelating agents, was developed. The use of sodium citrate (NaC) and sodium hexametaphosphate (SHMP) were more effective than other chelating agents. Yield results indicated that 47 to 69% of beta-Lg originally present in the whey preparations was recovered, with purities ranging from 84 to 95%, and protein contents ranging from 40 to 99%, while the yields of alpha-Lac were 23 to 89%, with purities ranging from 83 to 90%, and protein contents ranging from 65 to 96% depending on the source of whey protein preparations and type of chelating agents.
Structural and thermal properties of beta-Lg and alpha-Lac isolated fractions were studied using polyacrylamide electrophoresis (native and SDS), RP-HPLC, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and electrospray ionization mass spectrometry (ESI-MS). Results showed that all beta-Lg and alpha-Lac isolated fractions exhibit increased thermal stability and reversibility over standard proteins and difference in thermal properties were dependent on protein source. The relative intensity of the 1692 cm-1 band in the beta-Lg isolated fractions was dependent on the nature of the chelating agent, and disappearance of this band occurred at temperature higher than that of beta-Lg standard, indicating increased thermal stability of beta-Lg isolated fractions. Denaturation of apo-alpha-Lac was related to the gradual decrease in the alpha-helix band and accompanied by the gain in intensity of 1653 and 1641 cm-1 bands, while denaturation of holo-alpha-Lac was associated by breakdown of beta-sheet structure and increase in turns and unordered structures.
Changes in charge state distribution (CSD), as measured by ESI-MS of beta-Lg and alpha-Lac in response to pH and storage time, were only qualitative and were of relatively low resolution at basic pH. The hydrogen/deuterium (H/D) exchange results demonstrated that the conformation of holo-alpha-Lac was more stable than that of apo-alpha-Lac and conformation of beta-Lg variant B was more stable than beta-Lg variant A. Kinetics of H/D exchange indicated that alpha-Lac and beta-Lg fractions isolated from different whey protein sources have the same or improved conformational stabilities compared to that of alpha-Lac and beta-Lg standard. The covalent binding of 3 or more hexose residues to alpha-Lac enhanced its conformational stability, but covalent binding of two hexose residues to beta-Lg resulted in less stable conformation.
9
Lal, Sumit. "Biodegradable packaging from whey protein". Thesis, University of Auckland, 2012. http://hdl.handle.net/2292/13815.
Testo completoAbstract (sommario):
Biodegradable packaging films from whey protein concentrate were made in this study. A total of 46 formulations were made in the form of thin (50 - 120um) films by using solvent casting. Additives used in the formulations included plasticizers i.e glycerol and propylene glycol, chaotropic agent i.e guanidine thiocynate, gelation and crosslinker i.e glutaraldehyde. Tensile tests showed an increase in tensile strength with the addition of glutaraldehyde (1.2 v/v) and gelatin (upto 50% wt%). Addition of glycerol, propylene glycol and guanidine thiocynate increased elongation of films. Water vapor permeability and oxygen permeability of films containing glycerol, propylene glycol and guanidine thiocynate increased, while films made with gelatin, glutaraldehyde showed lower permeability for oxygen and water. Glass transition temperature was measured by DSC and results showed consistent decrease in Tg with increasing amount of plasticizer and chaotropic agent. Biodegradability was measured by degradation in 1% pancreatin. Results showed lower degradation time for formulations containing increasing proportions of glutaraldehyde and gelatin. Fourier transform infrared spectroscopy (FTIR) was used to evaluate changes in covalent bonding post glutaraldehyde crosslinking. Peaks corresponding to stretching of imine bonds were found at 1590 cm-1 suggesting crosslinking reaction between glutaraldehyde and terminal amine residues of whey/gelatin. Scanning electron micrographs showed an increase in relative porosity for compositions containing glycerol when compared to formulation containing only whey. Surface micrographs of formulations with gelatin showed phase separation. The phase separation may be attributed to partial immiscibility of whey with gelatin.
10
Steventon, Anthony James. "Thermal aggregation of whey proteins". Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/251549.
Testo completo
11
Howell, John Michael. "Whey permeate fouling of evaporators". Thesis, University of Canterbury. Chemical and Process Engineering, 1998. http://hdl.handle.net/10092/10686.
Testo completoAbstract (sommario):
Whey permeate fouling was studied to gain a better understanding of the processes involved and find methods of alleviation. An apparatus was built which allowed study of fouling under industrial conditions. It was found that pretreatment by heating at 80°C for two minutes and then centrifuging at 630 g reduced fouling in the apparatus by 94%. This was attributed to precipitation of calcium phosphate in the solution bulk during preheating, which reduced the level of supersaturation. Heat treatment with the same conditions but without centrifuging reduced fouling by only 39%. Precipitate which forms in the bulk of solution fouls in later heat treatment processes and separation of the precipitated mineral is needed to minimise fouling.
Storage time affected fouling. In the short term (about 2 weeks), fouling slightly increased with storage time. When held for longer times (about 1 month) whey permeate did not appreciably foul.
The use of additives was also found to be an effective alleviation method, reducing fouling by 66% with 0.1% addition (by dry weight) of tetrasodium pyrophosphate. This addition would increase the price of a ton of lactose by $16.32 /ton.
Nanoftltration, ion dialysis and electrodialysis were also examined, but rejected as being uneconomic.
By observing the effect of preheating and storage time it was proposed that calcium phosphate exists in whey in two forms. The majority of the minerals are associated with non-protein nitrogen (NPN) species, which tends to provide stability and prevent precipitation. In the other form the calcium phosphate is in solution as free ions. When the NPN species release minerals due to cleavage by enzymes or denaturation by heat, the concentration of ionic species increases past the solubility product and precipitation occurs.
12
Kamath, Savita. "Characterization of residual whey lipids /". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487935958848216.
Testo completo
13
Vendramin, Veronica. "Whey valorisation by microbial fermentation". Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3426766.
Testo completoAbstract (sommario):
Streptococcus thermophilus is a thermophilic lactic acid bacterium (LAB) of major importance in the dairy industry. This species is widely used as starter culture to produce fermented dairy products. It has been awarded the status of GRAS (Generally Recognized as Safe) in the USA and a Qualified Presumption of Safety (QPS) status in the European Union, due to its long history of safe use in food production. Increasing the number of starter available to producers by discovering new strains with desirable characters is important not only for identifying new properties that may better suited the needs of the industrial raising demand but also to preserve natural biodiversity, which is diminishing with the spread and overuse of commercial starters.
The progresses in high-throughput ‘omics’ technologies (‘Foodomics’) allows the development of more rational approaches aimed to improve fermentation processes both for the traditional foods productions and for new functional food products . Nevertheless, to date only few steps were made toward the in-depht analysis of the pan-genome and transcriptional regulation in species of food interest.
In this study the whole genome sequencing of eight S. thermophilus strains isolated from typical cheese-making processes in four Italian regions was performed using the Illumina platform. Genomic data were compared with the already available information in order to study the level of genetic biodiversity present within the species. In addition, some technological properties were analysed both genetically and phenotypically to integrate the knowledges at these two levels.
The applicative part of the study regarded the study of the strains during growth on milk whey, both from physiological and genetic (gene expression) standpoints. Particular effort was dedicated to production of vitamin, in particular folates. The obtained results, reported in this thesis, are interesting both from a scientific and applicative point of view.Streptococcus thermophilus appartiene ai batteri lattici (LAB) termofili ed è un microrganismo di primaria importanza nel settore caseario. Questa specie è largamente usata come starter nella produzione di prodotti caseari fermentati. Grazie alla sua lunga storia nella produzione di alimenti, gli è stato conferito lo stato di GRAS (Generally Recognized as Safe) negli Stati Uniti d’America e di QPS (Qualified Presumption of Safety) nell’Unione Europea. Aumentare il numero di ceppi starter disponibili per i produttori caseari, scoprendo ceppi autoctoni che posseggano caratteri tecnologicamente rilevanti, è importante non solo per identificare nuove proprietà che possano rispondere maggiormente alla crescente domanda, ma anche per preservare la naturale biodiversità che sta diminuendo con il diffondere e il sempre maggiore degli starter commerciali. I progressi attuali nelle tecnologie high throughput (‘Foodomics’) permettono lo sviluppo di approcci razionali per l’ottimizzazione del processo fermentativo sia nella tradizionale funzionalità alimentare sia nella nuova potenzialità dei prodotti nutraceutici. Tuttavia, non molti passi sono stati fatti verso l’analisi dettagliata della pan-genomica e della regolazione trascrizionale nelle specie di interesse alimentare. In questo studio, è stato portato a termine il sequenziamento completo del genoma di otto ceppi di S. themophilus isolati da processi di caseificazione tradizionali in varie località italiane. I dati genomici sono stati comparati con l’informazione disponibile nei database pubblici nel tentativo di studiare il livello di biodiversità genetica presente all’interno della specie. Inoltre, alcune proprietà tecnologicamente rilevanti sono state analizzate sia geneticamente sia fenotipicamente in modo da integrare le conoscenze a questi due livelli La parte applicativa dello studio ha riguardato lo studio dei ceppi durante la crescita in siero di latte, sia dal punto di vista fenotipico che dell’espressione genica, con particolare attenzione alla produzione di vitamine e specificamente di folati. I risultati ottenuti hanno prodotto informazioni interessanti sia dal punto di vista scientifico che, in prospettiva, da quello applicativo.
14
Mitchell, Muriel. "Effect of whey protein fortification on selected quality characteristics of some formulated tomato-whey beverages /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487265143147454.
Testo completo
15
Xue, Xin 1972. "Electrohydrodynamically-dried whey protein : electrophoretic and calorimetric analysis". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20605.
Testo completoAbstract (sommario):
Drying is an energy intensive process. The conventional heat-based drying methods often produce changes in the physico-chemical properties of products. A newly developed electrohydrodynamic (EHD) drying technique may be much less destructive to these heat-sensitive materials. This thesis presents comparative analyses of product deterioration in EHD-dried whey proteins, using electrophoresis, differential scanning calorimetry (DSC), and color measurements. Gel electrophoresis showed the disappearance of bands and reduction in band intensities depending upon the temperature of the oven in which the whey protein was dried. The thermograms of the differential scanning calorimeter varied considerably as the temperature of oven-drier increased. EHD, air-drying, and their combination showed no significant change in the electrophoretograms and thermograms compared with the native protein. Color measurements also indicated no significant change in color of EHD-dried whey protein whereas oven-drying produced darker colors from the original. These results allowed us to conclude that physico-chemical properties of whey protein remained intact after drying with EHD.
16
Olson, Amie L. "Efficacy of a whey permeate based sports drink". Online version, 2003. http://www.uwstout.edu/lib/thesis/2003/2003olsona.pdf.
Testo completo
17
Dlamini, Abednego Mfanufikile, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty e School of Applied and Environmental Sciences. "Microbial biopolymers from whey : production and applications". THESIS_FST_AES_Dlamini_A.xml, 1997. http://handle.uws.edu.au:8081/1959.7/322.
Testo completoAbstract (sommario):
The main aim of this research was to utilise whey as a fermentation substrate for the production of microbial biopolymers.Of the three commercial biopolymer producers tested for biopolymer production in whey, only Pseudodomonas elodea produced significant apparent viscosities of up to 470cP at 2 s-1 on enriched whey broths. In these broths lactose utilisation was poor (14% w/v). A strain of P. elodea that had improved lactose utilising capacity was selected after six serial transfers on whey and lactose rich broths. After screening more than 60 bacterial isolates, a strain of Klebsiella oxytoca that initially produced a broth apparent viscosity of 36 cP at 12 s-1 in whey was isolated from raw milk. Biopolymer production was optimised in the K. oxytoca isolate.Concentrations of over 16 g/1 and broth apparent viscosities greater than 20,000 cP at 0.6 s-1 were obtained after optimisation. The biopolymer produced by the K. oxytoca isolate was shown to contain rhamnose, glucose and cellobiose, a composition not comparable to any reported polysaccharide. Polymer application studies indicated that it had potential to be used as a thickener, stabiliser, and binder.Doctor of Philosophy (PhD)
18
Macedo, Antónia Teresa Zorro Nobre. "Fraccionamento de lactossoro de ovelha por tecnologias de membranas e estudo das possiveis utilizações dos concentrados obtidos". Doctoral thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/3871.
Testo completoAbstract (sommario):
Doutoramento em Engenharia Agro-Industrial - Instituto Superior de AgronomiaIn this thesis we studied the efficiency of fractionation of ovine whey by ultrafiltration followed by nanofiltration, in terms of permeation fluxes and apparent rejections. The application possibilities of the concentrates produced were also investigated. Ultrafiltration tests were performed in total recirculation mode under different operating conditions of transmembrane pressure and feed recirculation velocity with membranes ETNA10PP, GR81PP and GR61PP. The membranes ETNA10PP turned out to be the most appropriate for the separation of the whey protein fraction because they allowed higher permeate flux (higher productivity) with apparent rejections coefficients of the protein above 90% and low apparent rejections of lactose, providing a better separation between the two fractions (protein and fraction rich in lactose). So, the membranes ETNA10PP were used in the trials of ultrafiltration, in concentration mode, till a volume concentration factor (VCF) of 4.0. Samples of concentrates were taken for the VCF´s of 1.8, 2.0, 3.0 and 4.0, which were used to manufacture cheese whey, following the traditional process of production. Compared to traditional whey cheese, the curd made from protein concentrates have dried residues, ash and fat contents significantly lower than those determined in traditional whey cheese, whereas concentrations of protein and lactose and the hardness are significantly higher. The nanofiltration of ultrafiltration permeates, performed with membranes NFT50, allowed almost total recovery of lactose and organic matter, measured by chemical oxygen demand. The diafiltration of the lactose concentrates can be used for purposes of purification, according to the intended end application.
19
Turkmenoglu, Secil. "Organic Acids Production From Cheese-whey". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607709/index.pdf.
Testo completoAbstract (sommario):
In this study, production of organic acids from cheese-whey was studied. Optimization of organic acids production was performed in semi-batch and batch reactors. Two sets of experiments were performed. First set of experiments were performed in semi-batch reactors for the optimization of organic loading rate (OLR) and hydraulic retention time (HRT). As a result of Set 1 experiments optimum OLR was found to be 15 g COD l-1. Second set of experiments were performed in batch reactors by using the optimum OLR found in Set 1 experiments. Set 2 experiments were conducted to study the effect of using different seed cultures and Basal Media (BM) on Volatile fatty avid (VFA) production. Main acidogenesis products were acetic acid (Hac), butyric acid (Buty) and propionic acid (HPr) with smaller quantities of i-butyric acid (i-Buty), valeric acid (Val) and caproic acid (Cap). It was seen that BM had a suppressive effect on ethanol (EtOH) production while it stimulated the
VFA production. Higher VFA productions and variety of VFA types were observed in Test Reactors seeded with acidogenic culture (R3 and R6).
20
Pais, Joana Oliveira. "Bioconversion of cheese whey into polyhydroxyalkanoates". Doctoral thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/12043.
Testo completo
21
Queirós, Ana Sofia Batista. "Acid induced-gelation of whey proteins". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15473.
Testo completoAbstract (sommario):
Mestrado em Bioquímica - Bioquímica AlimentarTraditionally, whey protein (WP) gelation requires the application of heat, hence limiting the use of whey protein ingredients as gelling agents in foods sensitive to high temperatures. Acid-induced gelation has been shown to promote whey protein gel formation at room temperature, using acidulants. However, it requires the application of heat in the initial stages of the process to achieve partial denaturation of the protein and the formation of soluble aggregates. Gelation in the presence of weak organic acids at room temperature has been reported for shark myofibrils. Nevertheless, according to the literature, these conditions have not yet been tested in whey proteins. Therefore, the aim of this study was to investigate whey protein gelation at ambient temperature upon addition of weak organic acids (formic, acetic and propionic). The effect of protein concentration, acid concentration, pH and acid type on the sol-gel protein phase behavior was investigated by macroscopic observation. Phase diagrams were established to define the physical state of the WP systems as a function of protein and acetic acid concentration, and pH. Small strain oscillatory rheological measurements were performed in order to characterize the gelation times and the viscoelastic properties of the obtained gels. Differential scanning calorimetry was applied to investigate the denaturation behavior of the WP, under the studied concentration and ionic conditions. Rheological measurements and visual assessment of the prepared samples indicated that all formic, acetic and propionic acids have induced whey protein gelation. However, this process was shown to be highly dependent on protein concentration, acid concentration, pH and acid type, which also seemed to influence the appearance of the final gels. Therefore, increasing protein and acid concentrations resulted in decreased gelation times and led to the formation of increasingly turbid and opaque gels. WPI gelation was also shown to occur more rapidly as the pH increased towards the isoelectric point, promoting the formation of translucent gels which became more turbid at higher values of pH. Lastly, propionic acid was the fastest to induce gel formation, yielding opaquer gels, followed by acetic acid and formic acid which formed clearer gels. DSC results showed a decrease in the denaturation temperature of WP in the presence of the highest acetic acid concentration studied (2.8 mol L-1, pH 3.2) in relation to the protein with no added acid, from 78 to about 58 ºC, indicating the lower thermal stability of the proteins in the presence of high acetic acid concentrations, probably related to changes in the intramolecular interactions stabilizing the proteins and to consequent conformational changes in the proteins upon acid addition.
Tradicionalmente, a gelificação das proteínas do soro do leite requer aplicação de calor, limitando a utilização destes agentes gelificantes em alimentos sensíveis a elevadas temperaturas. É possível a gelificação destas proteínas induzida por ácidos à temperatura ambiente, através do uso de acidulantes, requerendo, contudo, a aplicação de calor numa fase inicial do processo. De acordo com a literatura, foi possível gelificar proteínas miofibrilares de tubarão na presença de ácidos orgânicos fracos. No entanto, não existem registos que indiquem a utilização destas condições para gelificar proteínas do soro do leite. Este trabalho teve como objetivo investigar a gelificação de proteínas do soro do leite, à temperatura ambiente, na presença de ácidos orgânicos fracos (fórmico, acético e propiónico). Os efeitos do tipo e concentração de ácido, concentração de proteína e pH sobre a transição de fase sol-gel foram estudados através da observação macroscópica de amostras em tubos de ensaio. Estabeleceram-se diagramas de fase para as proteínas do soro de leite em meio aquoso acidificado, em função das concentrações de proteína e ácido acético e do pH. Os tempos de gelificação e as propriedades viscoelásticas dos géis obtidos foram caracterizados através de ensaios reológicos dinâmicos a baixa deformação. A desnaturação destas proteínas, sob as diferentes condições em estudo, foi avaliada por calorimetria diferencial de varrimento. Os resultados dos ensaios reológicos e da avaliação visual das amostras indicaram que todos os ácidos estudados induziram a gelificação do isolado de proteínas do soro do leite. Contudo, este processo demonstrou ser altamente dependente da concentração de proteína e de ácido, do pH e do tipo de ácido, fatores estes que também influenciam o aspeto final dos géis. Assim, o aumento da concentração de proteína e de ácido resultou em tempos de gelificação menores e na formação de géis cada vez mais turvos e opacos. A gelificação destas proteínas também aconteceu mais rapidamente à medida que o pH aumentava e se aproximava do ponto isoelétrico, originando géis inicialmente translúcidos que se tornaram mais turvos a pH mais elevado. A formação de géis aconteceu de forma mais rápida na presença de ácido propiónico, seguindo-se o ácido acético e o ácido fórmico. No primeiro caso, foram produzidos géis translúcidos e opacos, enquanto os outros ácidos formaram géis mais transparentes. Os resultados de calorimetria mostraram a diminuição da temperatura de desnaturação do isolado de proteínas do soro de leite, de 78 para 58 ºC, para a concentração de ácido acético estudada mais elevada (2.8 mol L-1, pH 3,2), indicando a influência da presença do ácido na estabilidade térmica das proteínas, provavelmente uma consequência de alterações nas interações intramoleculares e na conformação destas proteínas.
22
Ramakrishnan, Sundaram. "Construction and properties of lactose utilizing brewers' and bakers' yeasts". Thesis, Imperial College London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266243.
Testo completo
23
Kumar, Vijay. "Cloning and expression of the Aspergillus niger Beta-Galactosidase gene in Saccharomyces cerevisiae". Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47141.
Testo completo
24
Dixon, Elizabeth Marie. "Whey Permeate, Delactosed Permeate, and Delactosed Whey as Ingredients to Lower Sodium Content of Cream Based Soups". NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-11072008-113327/.
Testo completoAbstract (sommario):
The use of whey permeates as salt substitutes can help to decrease sodium and chloride intake, increase potassium, calcium and magnesium intakes and decrease hypertension risk. Five different whey permeates from 5 different manufacturers were analyzed with ICP for mineral content (Na, K, Ca, Mg, Fe, Zn). Two permeates are powder and three are liquid. Lactose and protein content were also analyzed by Lactose/D-Glucose UV kit from Roche and BCA protein assay, respectively. Chloride and phosphate were measured spectrophotometrically. Basic tastes and aromas were quantified by a trained sensory panel. Based on the highest âsalty tasteâ identified by the trained sensory panel, one liquid and one solid permeate were further investigated as sodium substitutes. The sodium content of the guideline solutions for comparing salty taste of the permeates were used to calculate the equivalent concentrations of salt and permeate for salty taste in aqueous solution. Two soup formulations were used to test the use of permeate as a salt substitute; one retorted, canned, condensed cream soup base, and one fresh cream soup base. Each formulation of soup was tested on a separate day by 75 consumer panelists who averaged between 20 and 30 years of age. Four samples were given each day 0%, 50%, 100% of the standard salt content in condensed soup, and permeate at a content calculated to be equal in salty taste to the standard salt content. The permeate soup was ranked in salty taste slightly lower than the 50% sample for the fresh soup. In the retorted soups, the permeate was ranked slightly higher than the 50% sample. However, the fresh and retorted soup formulations made from permeate actually contained 11% and 19% sodium as compared to the 100% salt recipe, respectively. The permeate soup was described as higher in salty taste than expected based on actual sodium content, but not as high as predicted from the salty taste of the permeate in aqueous solution. Potassium and magnesium levels were increased in the formulations with permeate. This research gives an optimistic view on the possibility of whey permeates and their capability of replacing sodium in cream soups and other processed foods.
25
Kishta, Osama. "Enhancement of innate immune defence by supplementation with pressurized whey protein as compared to its native whey counterpart". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107623.
Testo completoAbstract (sommario):
Chronic pulmonary infection with Pseudomonas aeruginosa (P. aeruginosa) in patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) is associated with persistent inflammation, exuberant oxidative stress, increased mortality and morbidity. Studies showed that whey protein (a byproduct of the cheese-making process) or its components can enhance innate immune functions of neutrophils ex vivo and decrease bacterial metabolic activity in vitro. Whey-derived peptides enhanced innate defense functions of neutrophils ex vivo and protected mice against infection. Treatment of whey protein with hyperbaric pressure increases its digestibility, alters the spectrum of peptides available for systemic absorption, and enhances its antioxidant potential. Hence the overall objective of this thesis was to test the hypothesis that supplementation with pressurized whey protein can enhance the host's ability to clear microbial infection more efficiently compared to native whey. To this end we used a murine model of sustained pulmonary infection with P. aeruginosa. Our time course study demonstrated that both lung infection and inflammation (indexed by inflammatory cell count in lung lavage fluid, body weight loss and myeloperoxidase activity in lung tissue) peak or start to diminish at Day 3, then wane by Day 7 while airway lumen protein oxidation persists. Two groups of female C57BL/6 mice were then randomized to receive either native or pressurized whey-based diets for four weeks, after which they were infected with 8 x 105 CFUs/mouse of P. aeruginosa. Bacterial burden at Day 3 was 13-fold less in the pressurized whey group (p< 0.5) without associated changes in the inflammatory response. Further approaches were then undertaken to explore the mechanisms of these findings. We found that supplementation with pressurized whey increased airway lumen neutrophil bactericidal activity and superoxide anion production, reflecting a higher innate defense capacity. Airway protein oxidation was also reduced in the pressurized whey group. Airway pro-inflammatory cytokines also suggested reduced local responses in the pressurized whey group, with a 10-fold less granulocyte-macrophage colony stimulating factor and trends towards lower interleukin-1β and macrophage inflammatory protein-2. In conclusion, supplementation with pressurized whey protein can enhance innate immune defenses against microbes to a greater extent than native whey and represents a promising nutritional approach towards enhanced immune protection from infection.Les infections chroniques pulmonaires causées par Pseudomonas aeruginosa (P. aeruginosa) chez les patients atteints de fibrose kystique (FK) ou de maladies pulmonaires obstructives chroniques (MPOC) sont associées à une inflammation persistante, un stress oxydatif exubérant, ainsi qu'une mortalité et une morbidité accrues. Des études ont montré que les protéines du lactosérum (un sous-produit du processus de fabrication du fromage) ou ses composantes peuvent améliorer les fonctions immunitaires innées des neutrophiles ex vivo et peuvent diminuer l'activité métabolique des bactéries in vitro. Les peptides dérivés du lactosérum améliorent les mécanismes de défenses innées des neutrophiles ex vivo et protègent les souris contre l'infection. Le traitement des protéines du lactosérum avec une pression hyperbare augmente leur digestibilité, modifie le spectre de peptides disponibles pour l'absorption systémique et améliore son potentiel antioxydant. Donc l'objectif global de cette thèse était de tester l'hypothèse selon laquelle la supplémentation du lactosérum en protéines par pressurisation peut améliorer la capacité de l'hôte à éliminer l'infection microbienne par rapport au lactosérum natif. À cette fin, nous avons utilisé un modèle murin d'infection pulmonaire soutenue, causée par P. aeruginosa. Notre étude de décours temporel a démontré que l'infection pulmonaire et l'inflammation (indexés par le nombre de cellules inflammatoires dans le liquide de lavage pulmonaire, la perte de poids corporel et l'activité myéloperoxydase dans le tissu pulmonaire) culmine et commence à diminuer au jour 3, puis décroit jusqu'au jour 7 tandis que l'oxydation des protéines de la lumière des voies respiratoires persiste. Deux groupes de souris C57BL / 6 femelles ont ensuite été randomisés pour recevoir soit une diète à base de lactosérum natif ou à base de lactosérum supplémenté par pressurisation pendant quatre semaines, après quoi ils ont été infectés avec 8 x 105 UFC (unité formant une colonie) / souris de P. aeruginosa. La charge bactérienne au Jour 3 était 13 fois moins importante dans le groupe ayant reçu le lactosérum pressurisé et ce sans changement associé au niveau la réponse inflammatoire. D'autres approches ont alors été considérées afin d'étudier les mécanismes pouvant expliquer ces résultats. Nous avons constaté que le groupe ayant reçu une diète à base de lactosérum pressurisé, présentait une augmentation de l'activité bactéricide des neutrophiles présents dans la lumière des voies respiratoires, accompagné d'une production accrue d'anion superoxyde, traduisant une capacité de défense innée amplifiée. L'état d'oxydation des protéines des voies respiratoires a également été réduit dans le groupe ayant reçu le lactosérum pressurisé. Les cytokines pro-inflammatoires présentent dans les voies respiratoires suggèrent une réponse inflammatoire locale réduite dans le groupe ayant reçu le lactosérum pressurisé. En effet le facteur stimulant les colonies de granulocytes-macrophages est réduit par un facteur 10 et une tendance à la baisse est aussi observée pour l'interleukine-1β et la protéine inflammatoire des macrophages-2. En conclusion, la supplémentation avec de protéines de lactosérum pressurisé peut augmenter les défenses immunitaires innées contre les microbes dans une plus grande mesure que le lactosérum natif et représente une approche nutritionnelle prometteuse afin d'accroitre la protection immunitaire contre l'infection.
26
Xu, Yue, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty e School of Food Science. "Isolation and characterization of components from whey". THESIS_FSTA_SFS_Xu_Y.xml, 1996. http://handle.uws.edu.au:8081/1959.7/248.
Testo completoAbstract (sommario):
The structure, functionality, isolation methods and applications of whey components, particularly the proteins and lactose, have been extensively studied. These studies have had a great impact on the food industry where whey components are increasingly being used as food ingredients. Two generations of whey protein product, namely Lactalbumin, produced by heat-induced precipitation, and Whey Protein Concentration/ Isloate, produced by ultrafiltration/ ion exchange chromatography, have been commercialised. Crystalline lactose in the food and pharmaceutical grades is also being produced. Recently, research activities in whey fractionation have shifted to the isolation of the minor components. This thesis is aimed at developing a Total Whey Utilization strategy by which the several components of the whey stream would be completely recovered by fractionation, resulting in little or no residue to be disposed of in the wastewater stream. Therefore, this study was initially dedicated to the development of novel separation methods which would be suitable for the Total Whey Utilization process. The development of those techniques revealed some previously unknown feature of whey components. The mechanisms of the separation methods have been also investigated. Although crystallization is an efficient method for fractionation or purification, its disadvantage is that the mother liquor is a wastewater containing high salt and BOD (Biological Oxygen Demand). The chromatographic method has been investigated in this work to separate the mother liquor or permeate into lactose and mineral fractions such that a goal of this thesis, namely a 'clean' water stream after processing whey, can be finally achieved. These studies have focused on the effect of resin type, salt form of the resin and the operating conditions on the separation of the lactose and mineral fraction.Doctor of Philosophy (PhD)
27
Taylor, Stephen Murray. "Rheology and biochemistry of whey protein gels". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308255.
Testo completo
28
Farinha, Inês da Silva. "Optimization of bioplastics production from cheese whey". Master's thesis, FCT - UNL, 2009. http://hdl.handle.net/10362/2377.
Testo completoAbstract (sommario):
Dissertation presented in partial fulfillment of the requirements for the degree of
Master in BiotechnologyPolyhydroxyalkanoates (PHAs) are polyesters produced by a variety of microorganisms. Due to the similarity of chemical and physical properties with the conventional plastics, and full biodegradability, PHAs constitute one of the best alternatives for synthetic polymers replacement. However, the production costs of these biopolymers are very high when compared to synthetic polymers production. One way to reduce the production costs is the utilization of low cost raw materials, such as industrial wastes and by-products as carbon source. An example of raw material is cheese whey, a by-product form cheese industry rich in lactose (4-5%). In this work, cheese whey was supplied to Escherichia coli strains harbouring the PHB synthesis genes from Cupriavidus necator for the production of poly(3hydroxybutyrate) (PHB). During this study, diverse reactor operating strategies were tested: feeding controlled by pH under oxygen limitation, feeding without oxygen limitation and continuous feeding. The best results were achieved in a fed-batch system with feeding controlled by pH and oxygen limitation, where 44.93% of PHB content,33.76 g/L of PHB concentration, 78.65 g/L of active biomass concentration and a volumetric productivity of 0.57 gPHB/L.h, were obtained.
29
Taylor, Vicki Leanne. "Whey growth factor protection against chemotherapy drug-induced toxicity in vitro /". Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09PHT246.pdf.
Testo completo
30
Tuan, Chik Syed Mohd Saufi. "Mixed Matrix Membrane Chromatography for Bovine Whey Protein Fractionation". Thesis, University of Canterbury. Chemical and Process Engineering, 2010. http://hdl.handle.net/10092/3647.
Testo completoAbstract (sommario):
Whey protein fractionation is an important industrial process that requires effective large-scale processes. Although packed bed chromatography has been used extensively, it suffers from low processing rates due to high back-pressures generated at high flow rates. Batch chromatography has been applied but generally has a low efficiency. More recently, adsorptive membranes have shown great promise for large-scale protein purification, particularly from large-volume dilute feedstocks. A new method for producing versatile adsorptive membranes by combining membrane and chromatographic resin matrices has been developed but not previously applied to whey protein fractionation. In this work, a series of mixed matrix membranes (MMMs) were developed for membrane chromatography using ethylene vinyl alcohol (EVAL) based membranes and various types of adsorbent resin. The feasibility of MMM was tested in bovine whey protein fractionation processes.
Flat sheet anion exchange MMMs were cast using EVAL and crushed Lewatit® MP500 (Lanxess, Leverkusen, Germany) anion resin, expected to bind the acidic whey proteins β-lactoglobulin (β-Lac), α-lactalbumin (α-Lac) and bovine serum albumin (BSA). The MMM showed a static binding capacity of 120 mg β-Lac g⁻¹ membrane (36 mg β-Lac mL⁻¹ membrane) and 90 mg α-Lac g⁻¹ membrane (27 mg α-Lac mL⁻¹ membrane). It had a selective binding towards β-Lac in whey with a binding preference order of β-Lac > BSA > α-Lac. In batch whey fractionation, average binding capacities of 75.6 mg β-Lac g⁻¹ membrane, 3.5 mg α-Lac g⁻¹ membrane and 0.5 mg BSA g⁻¹ membrane were achieved with a β-Lac elution recovery of around 80%.
Crushed SP Sepharose™ Fast Flow (GE Healthcare Technologies, Uppsala, Sweden) resin was used as an adsorbent particle in preparing cation exchange MMMs for lactoferrin (LF) recovery from whey. The static binding capacity of the cationic MMM was 384 mg LF g⁻¹membrane or 155 mg LF mL⁻¹ membrane, exceeding the capacity of several commercial adsorptive membranes. Adsorption of lysozyme onto the embedded ion exchange resin was visualized by confocal laser scanning microscopy. In LF isolation from whey, cross-flow operation was used to minimize membrane fouling and to enhance the protein binding capacity. LF recovery as high as of 91% with a high purity (as judged by the presence of a single band in gel electrophoresis) was achieved from 150 mL feed whey.
The MMM preparation concept was extended, for the first time, to produce a hydrophobic interaction membrane using crushed Phenyl Sepharose™ (GE Healthcare Technologies, Uppsala, Sweden) resin and tested for the feasibility in whey protein fractionation. Phenyl Sepharose MMM showed binding capacities of 20.54 mg mL⁻¹ of β-Lac, 45.58 mg mL⁻¹ of α-Lac, 38.65 mg mL⁻¹ of BSA and 42.05 mg mL⁻¹ of LF for a pure protein solution (binding capacity values given on a membrane volume basis). In flow through whey fractionation, the adsorption performance of the Phenyl Sepharose MMM was similar to the HiTrap™ Phenyl hydrophobic interaction chromatography column. However, in terms of processing speed and low pressure drop across the column, the benefits of using MMM over a packed bed column were clear.
A novel mixed mode interaction membrane was synthesized in a single membrane by incorporating a certain ratio of SP Sepharose cation resin and Lewatit MP500 anion resin into an EVAL base polymer solution. The mixed mode cation and anion membrane chromatography developed was able to bind basic and acidic proteins simultaneously from a solution. Furthermore, the ratio of the different types of adsorptive resin incorporated into the membrane matrix could be customised for protein recovery from a specific feedstream. The customized mixed mode MMM consisting of 42.5 wt% of MP500 anionic resin and 7.5 wt% SP Sepharose cationic resin showed a binding capacity of 7.16 mg α-Lac g⁻¹ membrane, 11.40 mg LF g⁻¹ membrane, 59.21 mg β-Lac g⁻¹ membrane and 6.79 mg IgG g⁻¹ membrane from batch fractionation of 1 mL LF-spiked whey. A tangential flow process using this membrane was predicted to be able to produce 125 g total whey protein per L membrane per h.
31
Vaca, Mier Mabel. "Biconversion of cheese whey into fuels and solvents". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64481.
Testo completo
32
Perez, Hernandez Gabriela. "Use of ingredients and processing to control the stability of high whey protein concentration retort sterilized beverages". Texas A&M University, 2005. http://hdl.handle.net/1969.1/2344.
Testo completoAbstract (sommario):
Stable retorted whey protein beverages with 5% protein concentration were
prepared. The effect of protein concentration, fat concentration and homogenization
pressure on the heat stability and the stability of emulsions of sterilized whey protein
beverages was determined. Beverages containing >1% protein formed aggregates during
the heat treatment. Food grade additives were added to the beverages with >1% protein
to determine if the heat stability could be improved. Lecithins and polyphosphates
improved the heat stability while hydrocolloids decreased the heat stability. Lecithins
improved the heat stability of emulsions better than polyphosphates but polyphosphates
were more effective in beverages without fat. Lecithins modified by acetylation or
hydrolysis provided more protection against heat denaturation of proteins than regular
lecithin. Acetylated lecithin created the emulsions most stable against creaming.
Improvement in the emulsion stability by the use of phospholipids was associated with a
more negative charge at the interface of the fat droplets. The effect of polyphosphates
on the heat stability was related to the chain length of the polyphosphates. Short chain
polyphosphates (dp~4) were more effective than other polyphosphates. Polyphosphates
probably improved the heat stability of the systems by changing the structure of water
and this prevented aggregation of whey proteins. Hydrocolloids decreased heat stability
most probably through thermodynamic incompatibility that locally increased the
concentration of proteins and promoted aggregation during the heat treatment.The effect of homogenization pressure, concentration of acetylated lecithin, and
the concentration of short chain polyphosphate on the storage stability of retorted whey
protein beverages containing 5% protein and 3% fat was determined. The creaming
index and particle size index changed over 28 d of storage and indicated creaming of the
emulsions. The use of homogenization pressures of 55 and 90 MPa compared to 20 MPa
reduced the magnitude of the change of the particle size index and creaming index
during storage. Inclusion of polyphosphates reduced the storage stability of the
emulsions.
Optimization of parameters showed that emulsions formulated with 5% protein,
3% fat and 0.3% lecithin without polyphosphates and homogenized at 90 MPa had the
best stability after 28 d of storage.
33
Yan, Jing-Qing. "Anaerobic digestion of cheese whey in an upflow anaerobic sludge blanket reactor". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/31898.
Testo completoAbstract (sommario):
The anaerobic digestion of cheese whey was studied in an upfiow anaerobic sludge blanket reactor for its start-up characteristics, the effects of various process parameters, the effect of sulfate addition and the determination of optimal operating conditions.
Start-up of an UASB reactor treating cheese whey was extremely difficult due to its tendency to acidify. Various start-up strategies were tested to facilitate start-up and to ensure stable operation. Among the operating parameters, sludge loading rate was the most critical for proper start-up of the UASB reactor. The initial sludge loading rate during start-up period should not exceed 0.25 g COD/g VSS.
The response of whey digestion to several process parameters was investigated. Without
pH-control, over 97% COD removal was obtained for influent concentrations from 5 to 28.8 g COD/1 and HRT of 5 days. However, instability was observed when the influent concentration was increased to 38.1 g COD/1.
Gas production from whey is affected by organic loading rate (OLR). At an OLR less than 4 g COD/l-d, higher influent strength resulted in a higher methane production rate. When the OLR was greater than 6, higher strength feed or shorter hydraulic retention time (HRT) produced less methane.
From the profiles of substrate concentration measured at various levels above the bottom of the reactor, two reaction stages, acidogenesis and methanogenesis were distinguished.
It was experimentally illustrated that the rate of acidogenesis is much faster than the rate of methanogenesis in a whey anaerobic digestion system. The accumulation
of VFAs in the first stage being faster than its assimilation in the second stage creates a distinct acidogenic phase in the bottom of the reactor. The instability caused
by high influent concentration could be attributed to the accumulation of VFAs beyond the assimilative capacity of the methanogenic stage.
A set of empirical models for accumulation and degradation of VFAs was developed using linear regression analysis. The requirement for maintaining this system in a dynamic
balance was that the degradation capacity for VFA in the second stage be greater than the accumulation of VFA in the first stage. Based on this idea, the optimal influent concentration was given as between 25 to 30 g COD/1 for system stability.
A hypothesis was proposed in this study that a proper amount of sulfate may be applied to moderate the detrimental influence of excess hydrogen on a stressed anaerobic reactor. The effect of sulfate was tested to study the biochemical mechanism. The permissible influent COD concentration was increased from 30 g COD/1 to 50 g COD/1 by using sulfate addition. The pH in the reactor was on the average 0.8 units higher and the concentration of butyric acid in the acidogenic phase much lower with added sulfate than without sulfate addition. The significant improvement of process stability and treatment efficiency made by the addition of sulfate clearly illustrated that sulfate acted like a stimulator which helped to maintain conditions favorable to methanogenesis. The mechanism of this stimulation is explained according to thermodynamics and hydrogen regulation which suggested that sulfate is able to promote the β-oxidation of VFAs by consuming hydrogen.
A two-stage inhibition mechanism was proposed to explain the inhibition of high VFA concentrations and the stimulation of sulfate. Higher hydrogen pressure is the cause of preliminary inhibition, resulting in the accumulation of VFAs, which subsequently inhibit the activity and growth of methanogens in the second inhibition stage. The mechanism of inhibition of methanogens from VFAs was interpreted as being caused by the acidification of the internal cytoplasm and destruction of the pH gradient by non-ionized acids based on the theory of bacterial membrane transport. A new control strategy for stabilization
of an anaerobic system is recommended.
Under the optimal operating conditions based on the results in the first three steps, over 97% reduction of COD was achieved when the influent COD was 30 g /l using an HRT of 2 days, an OLR of 16.61 g COD/l-d and sulfate concentration of 0.2 g/1.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
34
D???Souza, Nisha Maria School of Chemical Engineering & Industrial Chemistry UNSW. "Influence of operating conditions on lifetime performance of membrane systems in whey processing". Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2005. http://handle.unsw.edu.au/1959.4/23309.
Testo completoAbstract (sommario):
Statistically designed experiments were conducted on a bench-scale ultrafiltration (UF) system using 10 kDa and 100 kDa polyethersulphone membranes to study the effect of operating conditions on membrane performance during whey processing. Experiments have underlined the importance of and provided a deeper understanding of factors influencing rejection. During filtration, a dynamic layer controlled protein fouling, reducing the effective molecular weight cut-off of the 100 kDa membrane and resulting in partial rejection. As pressure increases, the cake becomes denser allowing fewer and smaller passages for permeation, thereby increasing rejection of smaller solutes. Whey should be processed at high UF cross-flow velocities, relatively low transmembrane pressures, low feed concentrations and low temperatures. Low pressures help improve fractionation efficiency; high cross-flow velocities limit cake build-up and control cake thickness, thereby reducing specific cake resistance. Temperatures less than 10??C and pH values away from the protein iso-electric point inhibit bacterial growth and are compatible with protein, mineral and membrane stability. An existing model of dairy UF plants enabled determination of factors that affect membrane age and operational measures that minimise the effect of ageing. No significant effect of ageing was observed on performance at different volume concentration ratios (VCR). Operation at VCR 37 and 38 was capable of producing 80% whey protein concentrate (WPC). The effect of diafiltration water is improved when introduced over two loops with reallocation. Prevention of reallocation will dilute the total solids concentration in the retentate producing product that is out of specification. High protein rejections, lactose and ash rejection values between 5-15%, and non-protein nitrogen rejections below 50% are essential for producing 80% WPC. Fat rejection did not influence product quality although experimental studies show that fat concentration in liquid whey affects performance. Flux was the most influential measure of membrane life. Membrane elements in loops 11-12 did not require as frequent replacement compared to elements in loops 5-7 which are most susceptible to ageing. Emphasis should be placed on these elements for cleaning routines and operating conditions that minimise the effects of fouling in order to produce 80% WPC.
35
Mei, Fu-I. "Effect of processing on the composition, microstructure and functional properties of cheese whey protein concentrate". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1106156777.
Testo completo
36
Yan, Shunyao. "Dual Template Pore Engineering of Whey Powder Derived Carbon as Efficient Oxygen Reduction Reaction Electrocatalysts For Primary Zinc-Air Batteries". Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/24337.
Testo completoAbstract (sommario):
Oxygen reduction reaction (ORR) is one of the critical reactions in many energy storages and conversion systems, such as fuel cells and metal-air batteries. Cost-effective and high-performance electrocatalysts for oxygen reduction reactions are needed for many energy storage and conversion devices. This project will prove that whey powder, a cheap by-product in the production of cheese and casein, can be used as a sustainable precursor to produce heteroatom-doped carbon electrocatalysts for ORR. The compounds rich in N and S elements in whey powder can produce plentiful catalytic active sites. However, the reactants in ORR cannot easily reach these sites. A dual-template method was used to create a hierarchical and interconnected porous structure with micropores created by Zinc chloride (ZnCl2) and large mesopores generated by fumed Silicon dioxide(SiO2) particles. At the optimum mass ratio of whey power: ZnCl2: SiO2 at 1:3:0.8, the resulting carbon material has a large specific surface area at 1944.7 m2 g–1, containing 4.6 at.% of N with 50.4% as pyridinic N. This carbon material shows superior catalytic activity for ORR, with an electron transfer number of 3.88 and a large kinetic limiting current density of 45.40 mA cm–2. They were employed as ORR catalysts to assemble primary zinc-air batteries, which deliver a power density of 84.1 mW cm−2 and a specific capacity of 779.5 mAh g−1, outperforming batteries constructed using the commercial Pt/C catalyst. Our findings open new opportunities to use an abundant biomaterial, whey powder, to create high-value-added carbon electrocatalyst for emerging energy applications.
37
Liao, Shyh-Yuan. "Development of models to predict whey protein functionality /". The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260531957544.
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38
Boye, Joyce Irene Ashami. "Thermodynamic and structural properties related to the gelation of whey proteins". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28994.
Testo completoAbstract (sommario):
The gelling characteristics of whey proteins is governed by factors which affect the structural properties of the protein. To understand this structure gelling relationship, the following factors were investigated; protein concentration, heating temperature and time, pH, NaCl and sugars. The effect of these factors on the molecular structure and gelatin properties of whey protein concentrate (WPC), $ beta$-lactoglobulin ($ beta$-lg), $ alpha$-lactalbumin ($ alpha$-lac) and bovine serum albumin (BSA) were studied using polyacrylamide gel electrophoresis, HPLC, mass spectrometry, differential scanning calorimetry and Fourier transform infrared spectroscopy. The results showed that protein concentration affected textural properties without affecting the molecular structure of the whey proteins while heating temperature, pH and NaCl affected both molecular structure and the textural characteristics. NaCl and sugars increased the stability of whey proteins to thermal denaturation but decreased gel formation. $ beta$-lg formed an opaque gel at pH 3 and a translucent gel at pH 9; the peak temperature of denaturation was 84$ sp circ$C at pH 3 and 70$ sp circ$C at pH 9. At both acid and alkaline pH, denaturation of $ beta$-lg resulted in the formation of intermolecular $ beta$-sheet structures associated with aggregation. These $ beta$-sheet aggregate structures were also observed when $ alpha$-lac was heated at pH 3 and 5 but not at pH 7 and 9. At pH 7, heating $ alpha$-lac resulted in a loss of $ alpha$-helix, $3 sb{10}$-helix and $ beta$-sheet and an increase in turns. DSC showed two reversible transitions at 39.6$ sp circ$C (A) and 64.8$ sp circ$C (B). At pH 3, transition A was partially reversible (14%) while transition B was completely reversible. At pH 9, transitions A and B were completely irreversible and a translucent gel was formed. Bovine serum albumin (BSA) showed maximum stability to thermal denaturation at pH 5. Denaturation of BSA resulted in the loss of $
39
Joseph, Moses S. P. "Factors that affect the binding of heptane to whey protein concentrates /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024996176.
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Liu, Xiaoming. "Effect of high hydrostatic pressure on whey protein concentrate functional properties". Online access for everyone, 2004. http://www.dissertations.wsu.edu/Dissertations/Spring2004/X%5Fliu%5F050504.pdf.
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Kyle, Clinton. "Influence of magnetic field exposure and clay mineral addition on the fractionation of Greek yogurt whey components". Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19021.
Testo completoAbstract (sommario):
Master of ScienceFood Science Institute
Jayendra Amamcharla
Greek yogurt is one of the largest-growing sectors in the dairy industry accounting for over 25% of yogurt sales in the United States. Greek yogurt is produced by removing a portion of water and water soluble components from yogurt. Consequently, a large quantity of Greek yogurt whey (GYW) is being produced as a co-product. GYW is compositionally different from cheese whey, and thus poses economic and environmental challenges to the dairy industry. The objective of the present study was to evaluate two physical treatments as alternative methods for separating valuable GYW components: magnetic fluid treatment (MFT) and the addition of sepiolite, a clay mineral. A MFT chamber was designed using four pairs of neodymium magnets arranged to produce a magnetic field strength of 0.6 Tesla. Three batches of GYW each from two manufacturers were procured. A 2×3 factorial design was used with MFT or without MFT and the addition of zero, two, or four grams of sepiolite per 100g of GYW. The pH of GYW was adjusted to 7.2 using 5N NaOH solution, and the GYW was pumped at a rate of 7.5 L/min through the MFT system with or without MFT chamber attached. The sample was split into three sub-samples, heated to 80°C, and sepiolite was added as per the experimental design. The samples were centrifuged at 1,000g for five minutes. The top aqueous layer was separated and analyzed for total solids, ash, lactose, protein, calcium, phosphates, and sodium content along with color. MFT did not influence the analyzed whey components (P > 0.05) except for lactose. However, addition of sepiolite influenced protein content and a* and b* color values for the top aqueous layers (P < 0.05). Both levels of sepiolite addition resulted in about a 50% decrease in protein compared to original GYW. Adding two grams of Sepiolite per 100g of GYW from manufacturer 1 resulted in b* decreasing from 25.99 to 8.16 compared to treated GYW with no sepiolite. Sepiolite was found to have possible applications in the removal of proteins and color pigments in GYW.
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Alizadeh, Pasdar Nooshin. "Functional and structural characteristics of acid-hydrolyzed whey protein concentrate". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22844.
Testo completoAbstract (sommario):
Whey Protein Concentrate (WPC) is used as a functional ingredient in many food products. To increase the applicability of WPC as well as other food proteins, it is often necessary to enhance the functional properties of the protein. Various protein modification techniques can be used for this purpose; this includes chemical, physical and enzymatic modification. In present study acid hydrolysis, a chemical modification, was investigated as a means to improve functionality of WPC, emulsifying, foaming and gelatin. Most of the previous work on WPC has been directed at enzymatic hydrolysis.Dispersions of WPC (8%) in organic acids (0.5 N, 1 N and 1.5 N acetic acid, citric acid phosphoric acid and mixture of these acids) were subjected to acid hydrolysis (6, 18 and 48 h) and the effects of this modification on functional properties was assessed. The degrees of hydrolysis were measured and freeze-dried hydrolysates were evaluated for their foam capacity and stability, emulsifying activity and stability index and toughness. Highest foam capacity was found in the hydrolysate obtained using 0.5 N acetic acid (6 h hydrolysis, foaming capacity of 140%); acid hydrolysis increased foam stability, in general. In addition, acid hydrolysis did not affect emulsifying activity index but gave higher emulsifying stability index and toughness of prepared gels.
Results of PAGE indicated that acidic modification led to progressive decrease in the $ alpha$-lactalbumin and BSA. $ alpha$-lactalbumin was found to be the most sensitive protein with significant degradation after 6 h hydrolysis. (Abstract shortened by UMI.)
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Alu'datt, Muhammad Hussein. "Isolation and characterization of soybean and whey protein co-precipitates". Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81245.
Testo completoAbstract (sommario):
Protein co-precipitates were prepared from whey powder and soybean flour using various extraction and co-precipitation techniques. The effect of extraction and co-precipitation on co-precipitate yield was investigated. Native and sodium dodecyl sulfate polyacrylamide gel electrophoresis (Native-PAGE, SDS-PAGE) and light compound microscopy (LCM) were used to study the structure of the co-precipitates. The rheological and gelation properties of the co-precipitates were determined. Highest yield (45%) for NaOH/Isoelectric Point IEP-Heating-Cooling, co-precipitate was obtained using the following conditions of extraction; extraction temperature, 40°C; temperature of precipitation 95°C, and pH of precipitation was 4.5. The yield of co-precipitates was affected by chelating agents and pH of precipitation and temperature of precipitation. Native-PAGE showed that 2 new protein bands result from the interactions between whey and soybean proteins during preparation of the co-precipitate. SDS-PAGE showed that the new proteins dissociated to give the protein subunits of whey and soybean proteins. LCM results showed differences in microscopic structure between the whey and soybean protein precipitates and the protein co-precipitates. Gels were characterized by measurement of water holding capacity (WHC), gelation start temperature (GST) and denaturation start temperature (DST) and gel strength (GS). Gels (16%) from a protein co-precipitate Mixed Powder MP:NaOH/IEP-Cooling had higher WHC and GS than gels from whey protein precipitate, soybean protein precipitate and protein co-precipitates Mixed Extract ME:NaOH/IEP-Cooling and co-precipitates MP: and ME:NaOH/IEP-Heating-Cooling. The DST of protein co-precipitates was dependent on protein concentration and pH, while GST was relatively dependent on protein concentration.
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Moura, Israel Novaes de. "Caracterização e identificação de adulterações em Whey Protein por espectroscopia de fluorescência estacionária e resolvida no tempo". Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/5965.
Testo completoAbstract (sommario):
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O objetivo deste trabalho foi avaliar a caracterização e eficácia de diferentes técnicas da espectroscopia de fluorescência na detecção de adulterações em formulações de Whey Protein concentrado (WPC) em pó, a partir de sua mistura com substâncias de diferentes origens. Foram estudados dois diferentes lotes de WPC provenientes do mesmo fornecedor. Adulterações foram realizadas a partir da adição individual de Cafeína (Tratamento 1), Creatina (Tratamento 2) e Lactose (Tratamento 3) a 30% (m/m) em WPC e submetidas às análises de espectroscopia de fluorescência estacionária e resolvida no tempo, utilizando-se os comprimentos de onda de excitação de 275 e 335 nm. Quando excitadas a 275 nm, as amostras apresentaram pico de emissão a 335 nm aproximadamente, com uma banda de emissão em torno de 380 nm, característica apenas na amostra contendo cafeína, enquanto lactose e creatina não induziram alterações no espectro do WPC. Quando excitadas a 335 nm, as amostras apresentam picos de emissão com máximo em 425 e 470 nm, sem diferenciação por simples observação do espectro. Análise da distância Euclidiana evidenciou que, quando excitadas a 275 nm, os espectros completos dos tratamentos 2 e 3 foram semelhantes ao Controle 1 enquanto o Tratamento 1 foi diferente. Já na excitação a 335 nm todos os espectros foram semelhantes. Análise de Componentes Principais (PCA) confirmou a diferenciação do Tratamento 1 a 275 nm mas foi inconclusiva com a excitação de 335 nm, porém determinou pontos de interesse para estudos das derivadas dos espectros. Com as derivadas, foi possível a diferenciação entre os Tratamentos 2 e 3 nos dois comprimentos de onda, com enfoque em comprimentos de ondas específicos que podem ser decisivos na diferenciação das adulterações. Em relação a espectroscopia resolvida no tempo, o Tratamento 1 demonstrou valores da intensidade média do tempo de vida de emissão superior aos tratamentos 2 e 3 nos dois comprimentos de onda de excitação empregados. A adulteração com cafeína foi realizada na amostra Controle 2 e foi observado resultado semelhante quando comparada ao Controle 1. De maneira geral, a aplicação das técnicas de espectroscopia de fluorescência estacionária e resolvida no tempo possibilitou a caracterização das amostras utilizadas no estudo. Além disso, possibilitou a observação de diferenças entre as amostras controles e aquelas adulteradas, especialmente a adicionada de cafeína e excitada no comprimento de onda 275 nm, com ajuda de ferramentas matemáticas. Os resultados aqui obtidos corroboram com o fato de que as técnicas empregadas podem ser importantes na detecção de fraudes em produtos lácteos.
The objective of this work was to evaluate the characterization and efficacy of different fluorescence spectroscopy techniques in the detection of adulterations in formulations of Whey Protein Concentrate (WPC) powder, from its mixture with substances of different origins. Two different batches of WPC from the same supplier were studied. Adulterations were performed from the individual addition of Caffeine (Treatment 1), Creatine (Treatment 2) and Lactose (Treatment 3) at 30% (w / w) in WPC and subjected to stationary fluorescence spectroscopy and time-resolved fluorescence, using the excitation wavelengths of 275 and 335 nm. When excited at 275 nm, the samples showed an emission peak at approximately 335 nm, with an emission band around 380 nm, characteristic only in the sample containing caffeine, while lactose and creatine did not induce alterations in the WPC spectrum. When excited at 335 nm, the samples showed peak emission at 425 and 470 nm, without differentiation by simple observation of the spectrum. Euclidean distance analysis showed that, when excited at 275 nm, the complete spectra of treatments 2 and 3 were similar to Control 1 while Treatment 1 was different. Regarding the excitation at 335 nm, all spectra were similar. Principal Component Analysis (PCA) confirmed the differentiation of Treatment 1 at 275 nm but it was inconclusive with 335 nm excitation, however, it determined points of interest for spectra derivative studies. With the derivatives, it was possible to differentiate between Treatments 2 and 3 in the two wavelengths, focusing on specific wavelengths that can be decisive in the differentiation of adulterations. In relation to time resolved fluorescence spectroscopy, Treatment 1 demonstrated values of the mean emission lifetime higher over Treatments 2 and 3 at the two excitation wavelengths employed. The caffeine adulteration was performed in the Control 2 sample and a similar result was observed when compared to Control 1. In general, the application of stationary and time resolved fluorescence spectroscopy techniques allowed the characterization of the samples used in the study. In addition, it made possible the observation of differences between the control and adulterated samples, especially the one with caffeine added and excited at the wavelength 275 nm, with the help of mathematical tools. The results obtained here corroborate the fact that the techniques employed may be important in the detection of fraud in dairy products.
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Gillham, Charles Rupert. "Enhanced cleaning of surfaces fouled by whey proteins". Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/252317.
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Xue, Xin. "Electrohydrodynamically dried whey protein, electrophoretic and calorimetric analysis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ44316.pdf.
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Ayaka, Kamada. "Assembly of whey protein nanofibrils into macroscopic filaments". Thesis, KTH, Mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194450.
Testo completoAbstract (sommario):
Recently, it has been reported that the increasing number of plastic are significantly floated in the sea, because they are difficult to be degraded naturally. This lack of biodegradability requires us to develop new environmental-friendly material replacing current plastics. One promising composite of bio-friendly material is proteins, since there are abundant in our nature. Here, this study aims to exploit such proteins to form macroscopic fibers, which could open the new path to use of protein-based materials. We approach this in ‘bottom-up’ method, which means to combine the small pieces to develop large and complex materials. First, we made protein nanofibrils from native proteins, turning them from nanometer scale into microscopic scale. Subsequently, these nanofibrils are assembled into macrofibers, achieving macroscopic scale. Since the properties of final material are strongly depending on the assembly of thier building blocks, it is required to control the assembly system. We realize this with flow-focusing spinning setup, which enable to control the orientation of nanofibrils by the acceleration of the flow. We have tested some conditions of the nanofibrils, especially the morphology of fibrils such as flexible and straight fibrils, and identified essential parameters for the assembly of nanofibrils. These results give us not only the insight of complex assembly mechanism of proteins, but also the opportunity to develop the new protein-based material.
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Fairbrother, Paul. "The fermentation of cheese whey by Lactobacillus helveticus". Thesis, University of South Wales, 1991. https://pure.southwales.ac.uk/en/studentthesis/the-fermentation-of-cheese-whey-by-lactobacilius-helvecticus(32b72e44-3d2a-4fcb-85d4-9b34263bd05e).html.
Testo completoAbstract (sommario):
The lactic acid fermentation of cheese whey permeate by Lactobacillus helveticus was studied. Precipitate formation during autoclaving of whey permeate was examined. Precipitation was found to be pH and temperature dependent. Qualitative analysis suggested that the precipitate was a calcium-phosphate complex. Solubilisation was achieved both by acidification and use of the sequestering agent EDTA. Optimisation of L. helveticus growth in whey permeate was carried out using factorial design, as opposed to a traditional univariate approach. Using this technique, the variation of specific growth rate with pH, temperature and stiirer speed was assessed. Cell growth and lactic acid formation in whey permeate containing various supplements, were investigated. Yeast extract was the most effective nitrogen/growth factor supplement. Maximum lactic acid production was achieved in permeate containing yeast extract (0.75% w/v), Tween 80 (0.1% v/v) and sodium acetate (0.05% w/v). Optimisation of lactic acid production in supplemented whey permeate was performed using factorial design. Optimum conditions for both acid formation and cell growth were pH 5.9, temperature 42°C and stirrer speed 200 rpm. Fourier transform infrared spectroscopy was applied to the on line and off line quantitative analysis of lactose and lactic acid during the fermentation process. This technique enabled substrate and product levels to be assessed quickly and simply, with no sample pre-treatment. Continuous culture of L. helveticus in MRS medium and supplemented whey permeate was carried out. Substrate conversion and lactic acid productivity decreased with increasing dilution rate. Maximum productivity corresponded to a dilution rate of 0.3 h" 1, whereas minimum residual substrate occured at a dilution rate of 0.1 h' 1 . Translation of the fermentation process from bench scale (11) to pilot scale (161) appeared to be successful. Completion times, productivity and lactose utilisation compared favourably with bench scale results.
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Altıok, Duygu Tokatlı Figen. "Kinetic modelling of lactic acid production from whey/". [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/gidamuh/T000471.pdf.
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Wang, Yu. "Using whey protein gel as a model food to study dielectric heating of salmon". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/y_wang_121506.pdf.
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