Heat-related changes to the hydrophobicity of cheese whey correlate with levels of native β-lactoglobulin and α-lactalbumin

1992 ◽  
Vol 59 (4) ◽  
pp. 527-532 ◽  
Author(s):  
Geoffrey O. Regester ◽  
R. John Pearce ◽  
Victor W. K. Lee ◽  
Michael E. Mangino
Keyword(s):  
Cheese Whey ◽  
Binding Capacity ◽  
Whey Proteins ◽  
Surface Hydrophobicity ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Native Proteins ◽  
Native Whey ◽  
Induced Changes ◽  
Β Lactoglobulin

SummaryCorrelations were identified between levels of the native whey proteins, β-lactoglobulin and α-lactalbumin and the surface and total hydrophobicities of cheese whey in response to different heat treatments. Heat-induced changes in the native βlactoglobulin content and surface hydrophobicity of whey exhibited the most significant linear relationship while correlations between total hydrophobicity and the native proteins were less significant because of an atypical rise in the n−heptane-binding capacity of whey after high-temperature treatment. The content of native β-lactoglobulin in whey was more sensitive to heating than the content of native α-lactalbumin, while heat-related changes in the total hydrophobicity of whey were generally greater than similar changes in surface hydrophobicity.

Whey protein denaturation in heated milk and cheese whey

1979 ◽  
Vol 46 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Robyn M. Hillier ◽  
Richard L. J. Lyster
Keyword(s):  
Cheese Whey ◽  
Protein Denaturation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Skim Milk ◽  
Heat Stability ◽  
Second Order ◽  
First Order ◽  
Heated Milk ◽  
Native Whey

SUMMARYQuantitative polyacrylamide gel electrophoresis has been used to measure residual native whey proteins remaining after heat treatment of skim-milk and cheese whey in a kinetic study. The denaturation of α-lactalbumin (α-la) appeared to be first order, but was probably a second-order reaction displaying pseudo first-order kinetics. The denaturation of both β-lactoglobulin A and B (β-lgA and β-lgB) followed second-order kinetics while that of serum albumin was more complex, and could equally well be described as first or second order. Equations are given relating logk1(in s-1) to temperature for α-la denaturation in skim-milk between 70 and 95 °C and between 100 and 150 °C. Similarly, equations relating logk2(in lg-1s-1) to temperature are given for ²-lgA in skim-milk between 100 and 150 °C, and for ²-lgB between 95 and 150 °C. The relative heat stability of ²-lgA and ²-lgB was found to vary.Below 95 °C ²-lgA appeared slightly more thermostable than ²-lgB in skim-milk, and the same was observed in cheese whey below 100 °C. Above these temperatures ²-lgB appeared more stable than ²-lgA.Denaturation of ²-lgB was only slightly more rapid in skim-milk than in whey at temperatures below 95 °C, but was significantly slower at higher temperatures.

Flavor Release of the Tomato Flavor Enhancer, 2-Isobutylthiazole, from Whey Protein Stabilized Model Dressings

2011 ◽  
Vol 17 (2) ◽  
pp. 143-154 ◽  
Author(s):  
K.F. Christiansen ◽  
E. Olsen ◽  
G. Vegarud ◽  
T. Langsrud ◽  
P. Lea ◽  
...  
Keyword(s):  
Whey Protein ◽  
Complex Modulus ◽  
Headspace Analysis ◽  
Temperature Treatment ◽  
Whey Protein Concentrate ◽  
High Temperature Treatment ◽  
Flavor Release ◽  
Tomato Flavor ◽  
Β Lactoglobulin ◽  
Flavor Enhancer

A tomato flavor enhancer, 2-isobutylthiazole (IBT), was added (5 mg/kg) to dressings emulsified with either a whey protein concentrate-80 (WPC-80), a WPC-80 hydrolysate or β-lactoglobulin at high pressure (70 MPa) at either 20 or 75 °C. The short (2-4 min), high-temperature treatment left the proteins essentially unchanged. IBT addition gave a dominant, green tomato flavor that masked the intrinsic odor of the WPC-80 hydrolysate but enhanced bitter flavor. The sensory IBT odor intensity was determined by oil level (5-30%) and pH; pH 4.0 gave higher IBT odor than pH 6.5. The green (IBT) odor release correlated with the sensory viscosity (p = 0.001) and with instrumentally determined complex modulus (p = 0.001), but not to the dressings’ microstructure. The presence of small (<<1.5 µm) oil particles that were difficult to identify from images may explain why no correlation between green odor and microstructure was found. Headspace analysis significantly detected differences in the release of IBT from the different protein types: WPC-80 dressings released the most and β-lactoglobulin the least amounts of IBT into headspace. As this difference in release of IBT among proteins could not be verified by sensory analysis, it may bear no relevance for perception.

Heat-induced and other chemical changes in commercial UHT milks

2005 ◽  
Vol 72 (4) ◽  
pp. 442-446 ◽  
Author(s):  
Anthony J Elliott ◽  
Nivedita Datta ◽  
Boka Amenu ◽  
Hilton C Deeth
Keyword(s):  
Heat Treatment ◽  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Room Temperature ◽  
Whey Proteins ◽  
Thermally Induced ◽  
Heated Milk ◽  
Heat Treated ◽  
Induced Changes ◽  
Β Lactoglobulin

The properties of commercial directly and indirectly heated UHT milks, both after heating and during storage at room temperature for 24 weeks, were studied. Thermally induced changes were examined by changes in lactulose, furosine and acid-soluble whey proteins. The results confirmed previous reports that directly heated UHT milks suffer less heat damage than indirectly heated milk. During storage, furosine increased and bovine serum albumin in directly heat-treated milks decreased significantly. The changes in lactulose, α-lactalbumin and β-lactoglobulin were not statistically significant. The data suggest that heat treatment indicators should be measured as soon as possible after processing to avoid any misinterpretations of the intensity of the heat treatment.

scholarly journals Produção de β- galactosidase Através da Saccharomyces fragilis Cultivada em Soro de Queijo

2020 ◽  
Vol 24 (4) ◽  
pp. 337-342
Author(s):  
Gisele Murador ◽  
Alessandra Bosso ◽  
Hélio Suguimoto ◽  
Luiz Rodrigo Ito Morioka
Keyword(s):  
Carbon Source ◽  
Production Process ◽  
Dairy Products ◽  
Cheese Whey ◽  
Whey Proteins ◽  
Free Products ◽  
Aqueous Fraction ◽  
Texture Characteristics ◽  
Β Lactoglobulin ◽  
Cheese Production

O soro do queijo é um subproduto do processo de produção de queijo, sendo este a fração aquosa obtida após a coagulação das caseínas do leite. É rico em lactose, proteínas do soro do queijo (β-lactoglobulina e α-lactoalbumina), vitaminas e minerais. O Soro pode ser utilizado como meio de cultivo por diversos micro-organismos para produção da enzima β-galactosidase, pois estes utilizam a lactose como fonte de carbono. A β-galactosidase é umas das enzimas mais importantes para os laticínios, pois hidrolisa a lactose em glicose e galactose. A β-galactosidase é utilizada para melhorar as características tecnológicas e de textura de produtos lácteos e desenvolvimento de novos produtos isentos de lactose. A β-galactosidase pode ser obtida por diferentes espécies de micro-organismos como fungos, leveduras e bactérias, de animais, frutos e plantas. Porém as de origem microbiana são as de maior interesse para a indústria, uma vez que estas são consideradas seguras para o consumo e possuem maior rendimento.   Palavras-chave: Biotecnologia. Enzima. Fermentação. Lactase. Subproduto.   Abstract Cheese whey is a by-product of the cheese production process, which is the aqueous fraction obtained after the milk caseins coagulation. It is rich in lactose, cheese whey proteins (β-lactoglobulin and α-lactoalbumin), vitamins and minerals. Cheese whey can be used as a culture by several microorganisms for the enzyme β-galactosidase production, as they use lactose as a carbon source. Β-galactosidase is one of the most important enzymes for dairy products, as it hydrolyzes lactose into glucose and galactose. Β-galactosidase is used to improve the technological and texture characteristics of dairy products and  to develop  new lactose-free products. Β-galactosidase can be obtained by different species of microorganisms such as fungi, yeasts and bacteria, from animals, fruits and plants. However, those of microbial origin are of greater interest to the industry, since they are considered safe for consumption and have the highest earinings.   Keywords: Biotechnology. Enzyme. Fermentation. By-product.  

Binding of zinc to bovine and human milk proteins

1989 ◽  
Vol 56 (2) ◽  
pp. 235-248 ◽  
Author(s):  
Harjinder Singh ◽  
Albert Flynn ◽  
Patrick F. Fox
Keyword(s):  
Ionic Strength ◽  
Binding Sites ◽  
Binding Capacity ◽  
Equilibrium Dialysis ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Association Constants ◽  
Zn Concentration ◽  
Β Lactoglobulin ◽  
Scatchard Plots

SummaryZn binding by whole bovine and human casein and by purified bovine caseins and whey proteins was investigated by equilibrium dialysis. Bovine αs1 casein had the greatest Zn-binding capacity (˜ 11 atoms Zn/mol). Protein aggregation was observed as Zn concentration was increased and- the protein precipitated at a free Zn concentration of 1·7 mM. Zn binding increased with increasing pH in the range 5·4–7·0 and decreased with increasing ionic strength. Competition between Zn and Ca was observed for binding to αs1-casein indicating common binding sites for these two metals. Bovine β-casein bound up to 8 atoms Zn/ mol and precipitated at a free Zn concentration of ˜ 2·5 mM, while K-casein bound 1–2 atoms Zn/mol. Whole bovine and human casein bound 5–8 atoms Zn/mol and precipitated at a free Zn concentration of ˜ 2·0 mM. Scatchard plots for Zn binding to caseins showed upward convexity, possibly due to Zn-induced association of caseins. Apparent average association constants (K¯app) for all caseins were similar (log K¯app 3·0–3·2). Enzymic dephosphorylation of αs1- or whole bovine casein markedly reduced, but did not eliminate, Zn binding. Thus, phosphoserine residues appeared to be the primary Zn-binding sites in caseins. With the exception of bovine serum albumin. which bound over 8 atoms Zn/mol, the bovine whey proteins, β-lactoglobulin, α-lactalbumin and lactotransferrin, had little capacity for Zn binding.

The quantitative measurement of whey proteins using polyacrylamide-gel electrophoresis

1976 ◽  
Vol 43 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Robyn M. Hillier
Keyword(s):  
Gel Electrophoresis ◽  
Protein Denaturation ◽  
Quantitative Estimation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Skim Milk ◽  
Internal Standard ◽  
Polyacrylamide Gel ◽  
Native Whey ◽  
Β Lactoglobulin

SummaryA method is described for the quantitative estimation of a mixture of whey proteins by spectrophotometric scanning of the stained protein bands following polyacrylamide-gel electrophoresis. The incorporation of β-lactoglobulin A as an internal standard improves the accuracy of the technique. The method has been used to measure residual native whey proteins in milk after heating. Results are presented for whey protein denaturation in skim-milk after heat treatment at 130 and 140 °C for various periods of time.

scholarly journals Foam Fractionation Technology for Enrichment and Recovery of Cheese Whey Proteins

2020 ◽  
Author(s):  
Venkateswarlu Sunkesula ◽  
Anil Kommineni ◽  
Chenchaiah Marella ◽  
K. Muthukumarappan ◽  
Lloyd E. Metzger
Keyword(s):  
South Dakota ◽  
Protein Concentration ◽  
Cheese Whey ◽  
Whey Proteins ◽  
Enrichment Ratio ◽  
Foam Fractionation ◽  
Fractionation Process ◽  
Selective Enrichment ◽  
Four Levels ◽  
Β Lactoglobulin

Background: Foam fractionation technology works on the adsorptive bubble separation principle. This technique involves adsorption of the surface-active substances on to a gas-liquid interface and separation of these components from the liquid along with bubbles as foam. The foam separation technology has been successfully utilized in the recovery of proteins from solutions containing either a single protein or binary mixtures. To develop a foam fractionation technology for selective enrichment and recovery of whey proteins, it is essential to investigate the effect of different feed and process variables that affect the foam fractionation process. The aim of the current study was to investigate the effect of two important feed variables, such as pH and initial protein concentration on recovery and enrichment of total whey proteins as well as α-lactalbumin and β-lactoglobulin. Methods: All the experiments were conducted in Agriculture and biosystems engineering lab and Alfred Dairy Science lab at South Dakota State University, Brookings, South Dakota during 2011-2013. The experiments used four levels of initial protein concentration and five levels of feed pH. Yield and enrichment ratios were determined for total whey proteins, α-Lactalbumin (α-La) and β-Lactoglobulin (β-Lg). Result: Whey protein yields ranged from 51.58 to 90.92%, while the enrichment ratios were between 1.2 to 5. The yield of α-La varied from 59 to 94% and the highest enrichment ratio of 8.45 was obtained with the treatment combination of initial protein concentration of 109 mg/L and pH of 5.1. Selective enrichment of α-La over β-Lg was observed at a pH of 4.65 with α-La to β-Lg ratio of 0.49. These findings will be helpful in selective enrichment and recovery of valuable proteins from Cheddar cheese whey using the foam fractionation process.

scholarly journals The Use of Membrane Filtration to Increase Native Whey Proteins in Infant Formula

Dairy ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 515-529
Author(s):  
Yihong Chen ◽  
Michael Callanan ◽  
Colm Shanahan ◽  
John Tobin ◽  
Luke F. Gamon ◽  
...  
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Membrane Filtration ◽  
Whey Proteins ◽  
Skim Milk ◽  
Protein Isolate ◽  
Milk Formula ◽  
Native Proteins ◽  
Heat Treated ◽  
Native Whey

The introduction of membrane filtration during infant milk formula (IMF) processing represents an innovative approach to increasing native protein content compared to standard IMF. The objective of this study was to compare IMF powder produced using a standard process and IMF produced from raw bovine skim milk with added whey protein isolate using a split-stream process incorporating a ceramic 1.4 μm filter followed by a polyvinylidene difluoride polymeric 0.2 μm filter. Retentates from 0.2 μm microfiltration (MF) were blended with fat, lactose, and minerals and subsequently high-temperature treated (125 °C × 5 s). The heat-treated retentate was merged with the permeate from the 0.2 μm MF, homogenised, and spray-dried (referred to as membrane-filtered IMF or MEM-IMF). A control IMF was also produced using standard treatment (referred to as high-temperature IMF or HT-IMF) without membrane filtration. Both IMF products were characterised by high-performance liquid chromatography, particle size, and enzyme activity assays. MEM-IMF powder had significantly higher amounts of native (1.1 g per 100 g powder) and monomeric (1.48 g per 100 g powder) whey proteins when compared to 0.18 and 0.46 g per 100 g powder in HT-IMF, respectively. MEM-IMF also exhibited a lower degree of protein aggregation compared to HT-IMF. Comparison of microbial and Maillard by-products markers demonstrated that a safe IMF product could be produced at scale, although levels of the Maillard by-product marker, carboxymethyl-lysine, were not significantly reduced in MEM-IMF. This study demonstrates how membrane filtration can be used to retain native proteins during IMF manufacture.

scholarly journals Effect of Direct Viral–Bacterial Interactions on the Removal of Norovirus From Lettuce

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhangkai Xu ◽  
Zishu Liu ◽  
Jiang Chen ◽  
Songyan Zou ◽  
Yan Jin ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Foodborne Pathogen ◽  
Bacterial Pathogen ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Bacterial Strains ◽  
Bacterial Interactions ◽  
Simulated Environments ◽  
Encapsulated Bacteria ◽  
Short Time

Norovirus (NoV) is the main non-bacterial pathogen causing outbreaks of gastroenteritis and is considered to be the leading cause of foodborne illness. This study aims to determine whether lettuce-encapsulated bacteria can express histo-blood group antigen (HBGA)–like substances to bind to NoV and, if so, to explore its role in protecting NoV from disinfection practices. Fifteen bacterial strains (HBGA-SEBs) were isolated from the lettuce microbiome and studied as they were proved to have the ability to express HBGA-like substances through indirect ELISA detection. By using attachment assay, HBGA-SEBs showed great abilities in carrying NoVs regarding the evaluation of binding capacity, especially for the top four strains from genera Wautersiella, Sphingobacterium, and Brachybacterium, which could absorb more than 60% of free-flowing NoVs. Meanwhile, the direct viral–bacterial binding between HBGA-like substance-expressing bacteria (HBGA-SEB) and NoVs was observed by TEM. Subsequently, results of simulated environmental experiments showed that the binding of NoVs with HBGA-SEBs did have detrimental effects on NoV reduction, which were evident in short-time high-temperature treatment (90°C) and UV exposure. Finally, by considering the relative abundance of homologous microorganisms of HBGA-SEBs in the lettuce microbiome (ca. 36.49%) and the reduction of NoVs in the simulated environments, we suggested putting extra attention on the daily disinfection of foodborne-pathogen carriers to overcome the detrimental effects of direct viral–bacterial interactions on the reduction of NoVs.

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