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Whey
Kinds of Whey Terms modified by Whey Selected AbstractsOPTIMIZATION OF PERMEABILIZATION PROCESS FOR LACTOSE HYDROLYSIS IN WHEY USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2009GURPREET KAUR ABSTRACT To overcome the permeability barrier and prepare whole cell biocatalysts with high activities, permeabilization of Kluyveromyces marxianus var. lactis NCIM 3566 in relation to, -galactosidase activity was optimized using cetyltrimethylammonium bromide (CTAB) as permeabilizing agent. Permeabilized whole cells can be advantageous over pure enzyme preparations in terms of cost-effectiveness and increased stability maintained by the intracellular environment. Response surface methodology (RSM) was applied to optimize concentration of CTAB, temperature and the treatment time for maximum permeabilization of yeast cells. The optimum operating conditions for permeabilization process to achieve maximum enzyme activity obtained by RSM were 0.06% (w/v) CTAB concentration, 28C temperature and process duration of 14 min. At these conditions of process variables, the maximum value of enzyme activity was found to be 1,334 IU/g. The permeabilized yeast cells were highly effective and resulted in 90.5% lactose hydrolysis in whey. PRACTICAL APPLICATION , -Galactosidase is one of the most promising enzymes, which has several applications in the food, fermentation and dairy industry. However, the industrial applications of , -galactosidase have been hampered by the costs involved in downstream processing. The present investigation was focused on developing the low-cost technology for lactose hydrolysis based on permeabilization process. Disposal of lactose in whey and whey permeates is one of the most significant problems with regard to economics and environmental impact faced by the dairy industries. Keeping this in view, lactose hydrolysis in whey has been successfully performed using permeabilized Kluyveromyces marxianus cells. Hydrolysis of lactose using , -galactosidase converts whey into a potentially very useful food ingredient, which has immense applications in food industries. Its use has increased significantly in recent years, mainly in the dairy products and in digestive preparations. Lactose hydrolysis causes several potential changes in the manufacture and marketing of dairy products, including increased solubility, sweetness and broader fermentation possibilities. [source] EFFICACY OF SOUR WHEY AS A SHELF-LIFE ENHANCER: USE IN ANTIOXIDATIVE EDIBLE COATINGS OF CUT VEGETABLES AND FRUIT,JOURNAL OF FOOD QUALITY, Issue 5 2007JINHAN SHON ABSTRACT The effectiveness of edible coatings containing sour whey powder (SWP), compared with soy protein isolate (SPI) and calcium caseinate (CC), in reducing oxidative browning and moisture loss during storage (4C) of cut apples, potatoes, carrots, and onions was investigated. Oxidative discoloration, as determined by the Commission Internationale de I'Eclairage L*a*b* color scale, was significantly reduced (P < 0.05) by treatments over a storage time of 120 min. Loss of lightness was reduced by CC, SPI and SWP coatings. These respectively showed 2.7, 3.3 and 1.5% change of L* value in coated apples as compared with 7.4% in the control. Browning in cut potatoes was significantly reduced from a 145.1% increase in the a* value of the control to 45.9, 37.0 and 30.3% increase for CC, SPI and SWP treatments, respectively. The b* values also reflected the effectiveness of SWP. The moisture barrier effect, tested over a period of 5 days at 4C, was significantly better for the treatments than control. SWP was the best and significantly reduced moisture loss in potatoes and carrots by 40 and 59%, respectively, over control. Cut onions did not show any treatment effect both in terms of off-color development and moisture loss. The reasons for the excellent moisture barrier and antioxidative property of SWP were discussed. PRACTICAL APPLICATIONS Oxidative degradation of fresh fruits and vegetables is a major problem faced by the industry today. Most of the fresh produce is grown in the southwestern part of the country, requiring days of transportation to retail outlets. As the educated consumer is highly health conscious, any effort in extending the shelf life will have to be nonchemical, and preferably natural. Because of small profit margins, the intervention must also be inexpensive. Millions of MT of sour whey, a by-product of cottage whey manufacture, is wasted because of the lack of appropriate food applications. It is natural, nutritious and presently very inexpensive. Our research investigated the possibility of using this by-product as a final wash to enhance the so-called window of freshness of fresh produce and fruit. [source] CONSUMER PERCEPTION OF WHEY AND SOY PROTEIN IN MEAL REPLACEMENT PRODUCTSJOURNAL OF SENSORY STUDIES, Issue 3 2008JESSICA L. CHILDS ABSTRACT Meal replacement products including protein bars, shakes and powdered drinks have increased in demand and sales. The objective of this study was to assess the consumer perception of protein content and type and product claims for meal replacement beverages and bars. The impact of exercise frequency on product perception was also investigated. Focus groups were conducted with exercisers and nonexercisers. An adaptive conjoint analysis survey was subsequently developed and conducted (n = 138 consumers, ages 18,35 years). Relative importance of product attributes was determined through a realistic trade-off scenario. Utility scores were extracted and rescaled by the zero-centered differences method, and two-way analysis of variance was conducted to identify the differences between exercise frequency and product attributes. Both groups preferred bars to beverages, and no clear preferences were observed for protein type, which was consistent with focus group results of low knowledge/understanding of specific proteins. All respondents valued the products with low-fat/fat-free, calcium, all-natural, protein, vitamin/mineral, heart health and muscle-building claims. Exercisers viewed muscle-building claims as more important than nonexercisers. Nonexercisers viewed heart health, calcium and vitamin/mineral claims as more important than exercisers. Three distinct consumer clusters were identified, and both exercise groups were found in all three clusters, although exercise frequency influenced membership in two of the three clusters (P < 0.05). These findings can be used to develop and market meal replacement products to specific consumer groups while leveraging their specific and unique needs. PRACTICAL APPLICATIONS Conjoint analysis provides a useful model of how consumers think during the purchase process and an understanding of the motivation for purchase through the testing of possible claims or product attributes. By applying this method to the purchase process of meal replacement bars and beverages, those in the field of development of these products can benefit from this information by being able to understand the motivation for purchase by the targeted consumer. [source] Ultra Whey 99: a whey protein isolate case studyINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2001J R Neville A case history of the manufacture and use of whey protein isolate is presented and particular attention is paid to the nutritional and processing characteristics of Ultra Whey 99, a whey protein isolate manufactured by Volac International Ltd. The growth of the nutritional bar market in the USA is used to demonstrate the increasing demand for specialist products such as whey protein. [source] Factors affecting the attachment of micro-organisms isolated from ultrafiltration and reverse osmosis membranes in dairy processing plantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2009X. Tang Abstract Aims:, To identify the types of micro-organisms involved in the formation of biofilms on dairy ultrafiltration and reverse osmosis membranes and investigate factors affecting the attachment of those isolates. Methods and Results:, Micro-organisms isolated from industrial membranes following standard cleaning were identified using the API culture identification system. Thirteen different isolates representing eight genera were isolated and their ability to attach to surfaces was compared using a microtitre plate assay. Three Klebsiella strains attached best, while mixed strains of Pseudomonas and Klebsiella attached better than individual strains. Whey enhanced the attachment of the isolates. The micro-organisms were characterized according to cell surface hydrophobicity using the microbial adhesion to hydrocarbon (MATH) test, and cell surface charge by measuring the zeta potential. These cell surface characteristics did not show a clear relationship with the attachment of our strains. Conclusions:, A variety of different micro-organisms is associated with dairy ultrafiltration and reverse osmosis membranes after cleaning, suggesting several possible sources of contamination. The cleaning of these membranes may be inadequate. The attachment of the different isolates is highly variable and enhanced in the presence of whey. Significance and Impact of the Study:, Knowledge of persistent microflora colonizing dairy membrane systems will help develop strategies to mitigate biofilm development in this environment, improving hygiene in membrane processing plants. [source] Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B-441)JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2004Ali O Büyükkileci Abstract The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm,3 h,1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm,3 h,1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm,3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO4 ·H2O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose,1. Copyright © 2004 Society of Chemical Industry [source] Statistical analysis of catalyst degradation in a semi-continuous chemical production processJOURNAL OF CHEMOMETRICS, Issue 8 2001Eleftherios Kaskavelis Abstract The effect of decaying catalyst efficacy in a commercial-scale, semi-continuous petrochemical process was investigated. The objective was to gain a better understanding of process behaviour and its effect on production rate. The process includes a three-stage reaction performed in fixed bed reactors. Each of the three reaction stages consists of a number of catalyst beds that are changed periodically to regenerate the catalyst. Product separation and reactant recycling are then performed in a series of distillation columns. In the absence of specific measurements of the catalyst properties, process operational data are used to assess catalyst decay. A number of statistical techniques were used to model production rate as a function of process operation, including information on short- and long-term catalyst decay. It was found that ridge regression, partial least squares and stepwise selection multiple linear regression yielded similar predictive models. No additional benefit was found from the application of non-linear partial least squares or Curds and Whey. Finally, through time series profiles of total daily production volume, corresponding to individual in-service cycles of the different reaction stages, short-term catalyst degradation was assessed. It was shown that by successively modelling the process as a sequence of batches corresponding to cycles of each reaction stage, considerable economic benefit could be realized by reducing the maximum cycle length in the third reaction stage. Copyright © 2001 John Wiley & Sons, Ltd. [source] EFFECT OF OLIVE OIL AND GLYCEROL ON PHYSICAL PROPERTIES OF WHEY PROTEIN CONCENTRATE FILMSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2008MAJID JAVANMARD ABSTRACT Olive oil was incorporated into whey protein through emulsification to produce films. Whey protein films were prepared by dispersing 10% protein in distilled water; and plasticized with different levels of glycerol (glycerol : protein [Gly : pro ] = 0.5 and 0.6). Olive oil was added at different levels (oil : pro = 0.0, 0.2, 0.3 and 0.4). The emulsion films were evaluated for mechanical properties, water vapor permeability (WVP) and opacity. Increasing the levels of Gly or olive oil in the films led to decreases in modulus and tensile strength. Increasing Gly content of films at oil/pro ratios of 0.2, 0.4 led to slight increases in elongation (EL). Increasing the oil : pro ratio further resulted in a decrease in EL for all films. No significant difference in WVP and opacity was observed between films made from mixtures of various proportions of whey protein concentrate,Gly with increasing olive oil (addition) at all levels of the plasticizer. PRACTICAL APPLICATIONS The main advantages of using edible films are extending food shelf life, improving food quality, adding value to the edible film-forming polymer and reducing synthetic packaging materials. Whey, obtained as a by-product in cheese, is produced in large quantities and has excellent functional properties and could potentially be used for edible films. [source] The Impact of Antioxidant Addition on Flavor of Cheddar and Mozzarella Whey and Cheddar Whey Protein ConcentrateJOURNAL OF FOOD SCIENCE, Issue 6 2010I.W. Liaw Abstract:, Lipid oxidation products are primary contributors to whey ingredient off-flavors. The objectives of this study were to evaluate the impact of antioxidant addition in prevention of flavor deterioration of fluid whey and spray-dried whey protein. Cheddar and Mozzarella cheeses were manufactured in triplicate. Fresh whey was collected, pasteurized, and defatted by centrifugal separation. Subsequently, 0.05% (w/w) ascorbic acid or 0.5% (w/w) whey protein hydrolysate (WPH) were added to the pasteurized whey. A control with no antioxidant addition was also evaluated. Wheys were stored at 3 °C and evaluated after 0, 2, 4, 6, and 8 d. In a subsequent experiment, selected treatments were then incorporated into liquid Cheddar whey and processed into whey protein concentrate (WPC). Whey and WPC flavors were documented by descriptive sensory analysis, and volatile components were evaluated by solid phase micro-extraction with gas chromatography mass spectrometry. Cardboard flavors increased in fluid wheys with storage. Liquid wheys with ascorbic acid or WPH had lower cardboard flavor across storage compared to control whey. Lipid oxidation products, hexanal, heptanal, octanal, and nonanal increased in liquid whey during storage, but liquid whey with added ascorbic acid or WPH had lower concentrations of these products compared to untreated controls. Mozzarella liquid whey had lower flavor intensities than Cheddar whey initially and after refrigerated storage. WPC with added ascorbic acid or WPH had lower cardboard flavor and lower concentrations of pentanal, heptanal, and nonanal compared to control WPC. These results suggest that addition of an antioxidant to liquid whey prior to further processing may be beneficial to flavor of spray-dried whey protein. Practical Application:, Lipid oxidation products are primary contributors to whey ingredient off-flavors. Flavor plays a critical and limiting role in widespread use of dried whey ingredients, and enhanced understanding of flavor and flavor formation as well as methods to control or minimize flavor formation during processing are industrially relevant. The results from this study suggest that addition of an antioxidant to liquid whey prior to further processing may be beneficial to minimize flavor of spray-dried whey protein. [source] Foam fractionation of ,-lactalbumin and ,-lactoglobulin from a whey solutionASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009A. P. Shea Abstract Whey, a byproduct of cheese production, is often considered a waste stream. Separation and purification of whey proteins is a difficult and expensive task. Occasionally, it is transported out of the dairy plant for a per volume charge. One possible method to reduce the waste volume and disposal cost is to concentrate whey by foam fractionation and potentially produce a valuable coproduct, a concentrated whey protein solution. Foam fractionation is an adsorptive bubble separation method based on the hydrophobic/hydrophilic properties of proteins. In this study, foam fractionation was evaluated for the concentration of whey proteins, specifically ,-lactalbumin and ,-lactoglobulin, from a dilute whey protein solution. The effects of initial whey protein concentration (0.075 and 0.15 mg/ml), pH (3.8,5.5), superficial gas velocity (0.85 and 0.95 cm/s) and temperature (4 and 65 °C) on protein enrichment and recovery were examined. Higher enrichment was achieved with the lower initial protein concentration (0.075 mg/ml), and at pH values that were near the isoelectric points (pI) of ,-lactalbumin and ,-lactoglobulin (pH 3.8, 4.2, 4.5, and 5.2). Higher superficial gas velocity enhanced the amount of proteins recovered with a decrease in the enrichment. Cold temperature treatment and partial heat denaturation of whey proteins reduced enrichment and increased protein recovery simultaneously. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] The Impact of Antioxidant Addition on Flavor of Cheddar and Mozzarella Whey and Cheddar Whey Protein ConcentrateJOURNAL OF FOOD SCIENCE, Issue 6 2010I.W. Liaw Abstract:, Lipid oxidation products are primary contributors to whey ingredient off-flavors. The objectives of this study were to evaluate the impact of antioxidant addition in prevention of flavor deterioration of fluid whey and spray-dried whey protein. Cheddar and Mozzarella cheeses were manufactured in triplicate. Fresh whey was collected, pasteurized, and defatted by centrifugal separation. Subsequently, 0.05% (w/w) ascorbic acid or 0.5% (w/w) whey protein hydrolysate (WPH) were added to the pasteurized whey. A control with no antioxidant addition was also evaluated. Wheys were stored at 3 °C and evaluated after 0, 2, 4, 6, and 8 d. In a subsequent experiment, selected treatments were then incorporated into liquid Cheddar whey and processed into whey protein concentrate (WPC). Whey and WPC flavors were documented by descriptive sensory analysis, and volatile components were evaluated by solid phase micro-extraction with gas chromatography mass spectrometry. Cardboard flavors increased in fluid wheys with storage. Liquid wheys with ascorbic acid or WPH had lower cardboard flavor across storage compared to control whey. Lipid oxidation products, hexanal, heptanal, octanal, and nonanal increased in liquid whey during storage, but liquid whey with added ascorbic acid or WPH had lower concentrations of these products compared to untreated controls. Mozzarella liquid whey had lower flavor intensities than Cheddar whey initially and after refrigerated storage. WPC with added ascorbic acid or WPH had lower cardboard flavor and lower concentrations of pentanal, heptanal, and nonanal compared to control WPC. These results suggest that addition of an antioxidant to liquid whey prior to further processing may be beneficial to flavor of spray-dried whey protein. Practical Application:, Lipid oxidation products are primary contributors to whey ingredient off-flavors. Flavor plays a critical and limiting role in widespread use of dried whey ingredients, and enhanced understanding of flavor and flavor formation as well as methods to control or minimize flavor formation during processing are industrially relevant. The results from this study suggest that addition of an antioxidant to liquid whey prior to further processing may be beneficial to minimize flavor of spray-dried whey protein. [source] Optimization of process parameters by Taguchi method in the recovery of lactose from whey using sonocrystallizationCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2010S. R. Patel Abstract Anti-solvent crystallization of lactose in the presence of ultrasound will reduce crystal size and the level of agglomeration as compared to the commercial cooling crystallization. It offers a potential route to enhance the physical properties as well as the rapid recovery of lactose. Since lactose recovery itself can reduce biological oxygen demand of whey by more then 80%, recovery of lactose from dairy waste stream (whey) solves the problems of dairy industries by improving economics of whey utilization and pollution reduction. In the present study, recovery of lactose from partially deproteinated whey using an anti-solvent (acetone) by sonocrystallization was optimized for finding the most influencing operating parameters; such as sonication time, anti-solvent concentration, initial lactose concentration in the whey and initial pH of sample mixture at three levels using L9 -orthogonal method. The responses were analyzed for recovery of lactose from whey. The anti-solvent concentration and the sonication time were found to be most influencing parameters for the recovery of lactose and the recovery of lactose was found to be 89.03% at the identified optimized level. The crystal size distribution of recovered lactose was found to be narrower (2.5 , 6.5 ,m) as compared to the commercial lactose crystals (3.5 , 9.5 ,m). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Modulation of human humoral immune response through orally administered bovine colostrumFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2001Fang He Abstract Eighteen healthy volunteers were randomized into two treatment groups and consumed liquid prepackaged bovine colostrum whey and placebo for 7 days. On days 1, 3 and 5, an attenuated Salmonella typhi Ty21a oral vaccine was given to all subjects to mimic an enteropathogenic infection. The circulating antibody secreting cells and the expression of phagocytosis receptors of the subjects before and after oral immunization were measured with the ELISPOT assay and flow cytometry. All subjects responded well to the vaccine. No significant differences were observed in ELISPOT values for IgA, IgG, IgM, Fc, and CR receptor expression on neutrophils and monocytes between the two groups. There was a trend towards greater increase in specific IgA among the subjects receiving their vaccine with bovine colostrum. These results suggest that bovine colostrum may possess some potential to enhance human special immune responses. [source] Monitoring bacterial and archaeal community shifts in a mesophilic anaerobic batch reactor treating a high-strength organic wastewaterFEMS MICROBIOLOGY ECOLOGY, Issue 3 2008Changsoo Lee Abstract Shifts in bacterial and archaeal communities, associated with changes in chemical profiles, were investigated in an anaerobic batch reactor treating dairy-processing wastewater prepared with whey permeate powder. The dynamics of bacterial and archaeal populations were monitored by quantitative real-time PCR and showed good agreement with the process data. A rapid increase in bacterial populations and a high rate of substrate fermentation were observed during the initial period. Growth and regrowth of archaeal populations occurred with biphasic production of methane, corresponding to the diauxic consumption of acetate and propionate. Bacterial community structure was examined by denaturing gel gradient electrophoresis (DGGE) targeting 16S rRNA genes. An Aeromonas -like organism was suggested to be mainly responsible for the rapid fermentation of carbohydrate during the initial period. Several band sequences closely related to the Clostridium species, capable of carbohydrate fermentation, lactate or ethanol fermentation, and/or homoacetogenesis, were also detected. Statistical analyses of the DGGE profiles showed that the bacterial community structure, as well as the process performance, varied with the incubation time. Our results demonstrated that the bacterial community shifted, reflecting the performance changes and, particularly, that a significant community shift corresponded to a considerable process event. This suggested that the diagnosis of an anaerobic digestion process could be possible by monitoring bacterial community shifts. [source] Whey-derived free fatty acids suppress the germination of Candida albicans in vitroFEMS YEAST RESEARCH, Issue 2 2007Martin Clément Abstract Bovine whey from the cheese-making industry contains several bioactive factors that promote health and prevent disease. Although many efforts have been made over the years to show that immunoglobulins, lactoperoxidase, lactoferrin, lysosyme and small peptides present in whey have antimicrobial activities against several pathogenic microorganisms, such activities have not been investigated so far for the lipid fraction of whey. Here, we have used an in vitro assay-based fractionation procedure to show that free fatty acids derived from whey cream specifically inhibit the germination of Candida albicans, a morphologic change associated with pathogenicity. Further fractionation by HPLC demonstrated that this activity can be mainly attributed to lauric acid, myristoleic acid, linoleic acid and arachidonic acid. [source] Presence of biogenic amines in a traditional salted Italian cheeseINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2009N INNOCENTE Asino cheese is a traditional Italian cheese ripened in a special dilute brine (salmuerie), mixed with whey, milk and milk cream. The aim of this work was to ascertain whether this processing technology can influence amine production. The study demonstrated that biogenic amine content increased gradually in the Asino cheese during the soaking phase in brine. Moreover, the biogenic amine content of the salmuerie was very high and the salmuerie and the Asino cheese had a similar relative profile in amine content. These results suggested that the biogenic amines migrate from the brine into the cheese as a result of the concentration differential existing between the two systems. [source] Optimization of ingredients for the formulation of a direct acidified whey based lassi-like beverageINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2008KALYANI NAIR Samples of direct acidified whey based lassi like beverage were prepared with different proportions of guar gum, CMC and inulin and were examined for sensory and physical attributes. The optimisation was carried out using central composite rotatory design (CCRD) of response surface methodology (RSM). Response surface analysis revealed that sensory scores for flavour, consistency, colour and appearance and overall acceptability of lassi like beverage varied from 6.50 to 7.25, 6.16 to 7.12, 6.20 to 7.41 and 5.96 to 7.20 respectively. The results of analysis showed that all the examined model solutions had significant influence on the different parameters indicating that the statistical model designed for these attributes fitted well in all the aspects of model efficiency check (R2 >85%). [source] Antioxidative ability of native and thermized sour whey in oxidation-catalysed model systems,INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2007JINHAN SHON Antioxidative properties of sour (cottage) were evaluated with (thermized) and without (native) heat treatment (80°C for 30 min). A model system comprising a Tween 20 stabilized peanut oil in phosphate buffer (pH 7.0) emulsion containing lipid oxidation catalysts, FeCl3, H2O2 and ascorbate was used. Native sour whey powder (SWP) was significantly better than thermized whey in terms of limiting the formation of thiobarbituric acid-reactive substances and peroxide value. Antioxidative ability was best at pH 3.0 and decreased with increasing pH. SWP (20%, w/v) was significantly better than all commonly used antioxidants tested after 96 h of incubation at 40°C. [source] Rennin-like milk coagulant enzyme produced by a local isolate of MucorINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2003Z A Tubesha Among 20 isolates of Mucor isolated from various environments in Jordan and found to produce a rennin-like acid protease, known as Mucor rennin-like enzyme (MRE), Mucor J20 was found to produce the highest level of MRE. The optimum incubation conditions for enzyme production in a fortified wheat bran mixture using solid-state fermentation were 3,4 days at 30°C. The highest MRE activity (185,200 rennin units or RU) was produced in a medium containing wheat bran and lentil straw (1 : 1 w/w) moistened with whey, and incubated in clay pots at 30°C for 4 days. A slightly lower activity value (178 RU) was found when using a mineral salt solution or distilled water instead of whey, or when using wheat bran alone with whey. At pH 4, the MRE retained its complete activity (100%) for 6 weeks at 5°C and 10°C, and for 3 and 2 weeks at 20°C and 30°C, respectively. After heating at 60°C for 10 min, the enzyme lost its activity at all pH levels used (pH 2,8). The crude extract of MRE was successfully applied in the manufacture of a cheese curd. [source] Milk sugars and minerals as ingredientsINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2001Matti Harju Lactose is the natural carbohydrate source and prebiotic compound found in the milk of mammals, but large variations in lactase activity in the small intestines of adult populations can cause problems with its use. The value of lactose can be increased by hydrolysis, but even more valuable products can be made by changing the structure of lactose and preventing its absorption in the gut. Some of these nonabsorbable lactose derivatives are already used in medical and functional food applications. Calcium phosphate precipitation to the heat-transfer surfaces is one of the oldest problems of the dairy industry, but if precipitation is carried out in controlled conditions, the precipitate can be further processed to form milk calcium powder. Milk calcium can be used as a natural source of calcium in calcium-fortified dairy products. The mineral and salty taste of whey has reduced its use as a food ingredient. The use of modern membrane technology offers a means of producing whey salt as a by-product of whey demineralization. These otherwise wasted minerals can then be used as a natural mineral salt. Especially interesting is the possibility of recycling the whey salt into cheese, improving its nutritional status. [source] The effect of coagulants on the texture of chhana (an acid and heat coagulated product made from milk)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2005Mahuya Bandyopadhyay Summary Chhana (a heat and acid coagulated milk protein mass and an Indian equivalent to cottage cheese) can be used as a raw material for the manufacture of various types of sweets popular all over India. Texture Profile Analysis (TPA), using an Instron Universal Testing Machine, was used to determine the effect of different coagulants on the textural characteristics of chhana. Chhana was made using three different coagulants: citric acid, lactic acid and calcium lactate, at five different concentrations, 0.5, 1, 2, 4 and 8%. Two types of dilution media, distilled water and acid whey, were used. The textural characteristics obtained when aqueous 0.5% citric acid, aqueous 0.5% lactic acid and 4,8% calcium lactate solutions, using acid whey as the solvent, gave similar TPA readings to normal chhana. [source] Batch kinetics and modelling of ethanolic fermentation of wheyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2005Salman Zafar Summary The fermentation of whey by Kluyveromyces marxianus strain MTCC 1288 was studied using varying lactose concentrations at constant temperature and pH. The increase in substrate concentration up to a certain limit was accompanied by an increase in ethanol formation, for example, at a substrate concentration of 10 g L,1, the production of ethanol was 0.618 g L,1 whereas at 50 g L,1 it was 3.98 g L,1. However, an increase in lactose concentration to 100 g L,1 led to a drastic decrease in product formation and substrate utilization. The maximum ethanol yield was obtained with an initial lactose concentration of 50 g L,1. A method of batch kinetics was utilized to formulate a mathematical model using substrate and product inhibition constants. The model successfully simulated the batch kinetics observed at S0 = 10 and 50 g L,1 but failed in case of S0 = 100 g L,1 because of strong substrate inhibition. [source] A traditional fermented Turkish soup, tarhana, formulated with corn flour and wheyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2004Zekai Tarakç First page of article [source] Factors affecting the attachment of micro-organisms isolated from ultrafiltration and reverse osmosis membranes in dairy processing plantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2009X. Tang Abstract Aims:, To identify the types of micro-organisms involved in the formation of biofilms on dairy ultrafiltration and reverse osmosis membranes and investigate factors affecting the attachment of those isolates. Methods and Results:, Micro-organisms isolated from industrial membranes following standard cleaning were identified using the API culture identification system. Thirteen different isolates representing eight genera were isolated and their ability to attach to surfaces was compared using a microtitre plate assay. Three Klebsiella strains attached best, while mixed strains of Pseudomonas and Klebsiella attached better than individual strains. Whey enhanced the attachment of the isolates. The micro-organisms were characterized according to cell surface hydrophobicity using the microbial adhesion to hydrocarbon (MATH) test, and cell surface charge by measuring the zeta potential. These cell surface characteristics did not show a clear relationship with the attachment of our strains. Conclusions:, A variety of different micro-organisms is associated with dairy ultrafiltration and reverse osmosis membranes after cleaning, suggesting several possible sources of contamination. The cleaning of these membranes may be inadequate. The attachment of the different isolates is highly variable and enhanced in the presence of whey. Significance and Impact of the Study:, Knowledge of persistent microflora colonizing dairy membrane systems will help develop strategies to mitigate biofilm development in this environment, improving hygiene in membrane processing plants. [source] The effect of carbon and nitrogen sources on bovicin HC5 production by Streptococcus bovis HC5JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2009A.A.T. De Carvalho Abstract Aims:, To investigate the effect of media composition and agroindustrial residues on bovicin HC5 production by Streptococcus bovis HC5. Methods and Results:, Batch cultures of S. bovis HC5 were grown in basal medium containing different carbon and nitrogen sources. The activity of cell-free and cell-associated bovicin HC5 was determined in culture supernatants and acidic extracts obtained from cell pellets, respectively. Streptococcus bovis HC5 produced bovicin using a variety of carbon and nitrogen sources. The highest specific activity was obtained in media containing 16 g l,1 of glucose, after 16 h of incubation. The peak in cell-free and cell-associated bovicin HC5 activity was detected when S. bovis HC5 cultures reached stationary phase. The bovicin HC5 specific activity and bacterial cell mass increased approximately 3-fold when yeast extract and trypticase (0·5 and 1·0 g l,1, respectively) were added together to the basal medium. Streptococcus bovis HC5 cultures produced bovicin HC5 in cheese whey and sugar cane juice and maximal volumetric productivity was obtained after 12 h of incubation. Conclusions:,Streptococcus bovis HC5 is a versatile lactic acid bacterium that can utilize several carbon and nitrogen sources for bovicin HC5 production. This bacterium could be a useful model to study bacteriocin production in the rumen ecosystem. Significance and Impact of the Study:, The use of agroindustrial residues as carbon sources could have an economical impact on bovicin HC5 production. To our knowledge, this is the first report to show the use of sugar cane juice for bacteriocin production by lactic acid bacteria. [source] Characterization of lactic acid bacteria strains on the basis of neutral volatile compounds produced in wheyJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2001G. Mauriello G. MAURIELLO, L. MOIO, G. MOSCHETTI, P. PIOMBINO, F. ADDEO AND S. COPPOLA. 2001. Aims: Seventy-eight strains of lactic acid bacteria belonging to five genera and showing six different phenotype combinations of Lac (lactose fermentation), Prt (proteolytic activity) and Cit (citrate degradation) characters were investigated for their main flavouring properties with the aim to detect variability among and within the groups. Methods and Results: High resolution gas chromatography,mass spectrometry analysis of neutral volatile compounds produced in whey showed that, considering both neo-formation compounds and substances quantified in the whey cultures at different concentrations in comparison to the extract from sterile whey, the groups of lactococci, enterococci, thermophilic streptococci and mesophilic lactobacilli produced a higher number of volatiles than thermophilic lactobacilli and leuconostocs. Applying principal component analysis (PCA) to the results, enterococci, mesophilic lactobacilli and thermophilic streptococci showed a broad diversity, while lactococci included rather similar strains as well as strains with special flavouring properties. Applying PCA to thermophilic streptococci and enterococci, to lactococci and enterococci, to lactococci and thermophilic streptococci, or to mesophilic and thermophilic lactobacilli, the strains gathered consistently with their systematic position. Conclusions: The study evidenced strains producing some volatile compounds responsible for food flavouring. Flavouring properties were variable among the systematic groups and in some cases different within the same bacterial group. Significance and Impact of the Study: The potential of the findings is discussed with reference to the development of flavouring adjuncts for the dairy industry. [source] Studies on glass transition temperature of mono and bilayer protein films plasticized by glycerol and olive oilJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Babak Ghanbarzadeh Abstract Thermomechanical and thermal properties of whey protein, maize prolamin protein (zein), and the laminated whey protein,zein films were studied. The dynamic mechanical (thermal) analysis (DMTA) results showed that the single zein film had higher Tg than single whey protein and zein,whey laminated films. The shift in the Tg values of films from 31.2°C in whey protein film and 88.5°C in the zein film to 82.8°C in the laminated whey protein,zein films may be implied some interaction formation between the two polymers. The small tan , peaks were observed at ,50°C in zein,glycerol films and at ,22.37°C in the whey protein films and can be related to ,-relaxation phenomena or presence of glycerol rich region in polymer matrix. Zein-olive oil and zein,whey protein,olive oil films showed tan , peaks corresponded the Tg values at 113.8, and 92.4°C, respectively. Thus, replacing of glycerol with olive oil in film composition increased Tg. A good correspondence was obtained when DSC results were compared with the tan , peaks in DMTA measurements. DSC thermograms suggested that plasticizers and biopolymers remained a homogeneous material throughout the cooling and heating cycle. The results showed that Tg of zein,glycerol films predicted by Couchman and Karasz equation is very close to value obtained by DSC experiments. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B-441)JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2004Ali O Büyükkileci Abstract The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm,3 h,1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm,3 h,1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm,3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO4 ·H2O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose,1. Copyright © 2004 Society of Chemical Industry [source] Unstructured model for seed cultures without pH control of Lactobacillus helveticus growing on supplemented whey permeateJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2002Abdeltif Amrane Abstract In cultures of Lactobacillus helveticus with pH controlled at 5.9, growth and lactic acid production were under the control of nutritional limitations (carbon and nitrogen). In the absence of pH control, as was the case for seed cultures, an inhibitory effect on growth of both pH and the undissociated lactic acid concentration were evident before nutritional limitations. The variations of the specific growth rate with the undissociated lactic acid concentration followed exponential decay. Then, the inhibitory effect of pH was also taken into account through the Henderson,Hasselbach equation. The specific growth rate history has been previously found to follow sigmoidal variation. Integration of these relationships gave the theoretical biomass and lactic acid production kinetics. The model fitted experimental kinetic data well and allowed fine analysis of the various growth phases, since the growth-associated, the deceleration and the stationary states can be characterized by means of the model parameters. © 2002 Society of Chemical Industry [source] OPTIMIZATION OF PERMEABILIZATION PROCESS FOR LACTOSE HYDROLYSIS IN WHEY USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2009GURPREET KAUR ABSTRACT To overcome the permeability barrier and prepare whole cell biocatalysts with high activities, permeabilization of Kluyveromyces marxianus var. lactis NCIM 3566 in relation to, -galactosidase activity was optimized using cetyltrimethylammonium bromide (CTAB) as permeabilizing agent. Permeabilized whole cells can be advantageous over pure enzyme preparations in terms of cost-effectiveness and increased stability maintained by the intracellular environment. Response surface methodology (RSM) was applied to optimize concentration of CTAB, temperature and the treatment time for maximum permeabilization of yeast cells. The optimum operating conditions for permeabilization process to achieve maximum enzyme activity obtained by RSM were 0.06% (w/v) CTAB concentration, 28C temperature and process duration of 14 min. At these conditions of process variables, the maximum value of enzyme activity was found to be 1,334 IU/g. The permeabilized yeast cells were highly effective and resulted in 90.5% lactose hydrolysis in whey. PRACTICAL APPLICATION , -Galactosidase is one of the most promising enzymes, which has several applications in the food, fermentation and dairy industry. However, the industrial applications of , -galactosidase have been hampered by the costs involved in downstream processing. The present investigation was focused on developing the low-cost technology for lactose hydrolysis based on permeabilization process. Disposal of lactose in whey and whey permeates is one of the most significant problems with regard to economics and environmental impact faced by the dairy industries. Keeping this in view, lactose hydrolysis in whey has been successfully performed using permeabilized Kluyveromyces marxianus cells. Hydrolysis of lactose using , -galactosidase converts whey into a potentially very useful food ingredient, which has immense applications in food industries. Its use has increased significantly in recent years, mainly in the dairy products and in digestive preparations. Lactose hydrolysis causes several potential changes in the manufacture and marketing of dairy products, including increased solubility, sweetness and broader fermentation possibilities. [source] | |||||||||||||||||||||||||||||||