Enzyme-induced gelation of whey proteins: Effect of protein denaturation

Ju, Zhou; Otte, Jeanette; Zakora, M.; Qvist, K.B.

doi:10.1016/s0958-6946(96)00043-x

Cited by 41 publications

(50 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Protein gelation is thought to be a result of protein unfolding (denaturation) followed by protein-protein agglomeration of the unfolded proteins, resulting in a covalently bonded network of cross linked peptides (Ju et al, 1997;Foegeding, 1992). Protein gelation is greatly influenced by the concentration of protein, the structure of protein, the surface properties of protein and physio-chemical properties of each individual protein (Marangoni et al, 2000).…”

Section: Gelationmentioning

confidence: 99%

“…While studying the effect of denaturation on the gelation of whey proteins, (Ju et al, 1997) found that gelation capabilities were a reflection of secondary and tertiary structural denaturation. It is observed that the higher percentages of the whey protein denatured prior to gelation correlated with decreased time for gelation and firming as well as increased gel strength.…”

Section: Gelationmentioning

confidence: 99%

“…SE-HPLC can be used to quantify denaturation based on the decrease of the peak area for each protein, reporting percent denaturation as a percentage of the peak area of the samples corresponding to a defined undenatured sample (Ju et al, 1997). They determined the percentage of denaturation in a control whey protein isolate, WPI solution by calculating the difference between total protein and protein content in the supernatant after performing a precipitation at pH 4.6 using nitrogen determinations by the Kjeldahl method.…”

Section: High Performance Liquid Chromatography (Hplc)mentioning

confidence: 99%

“…HPLC is one of the most widely used analytical methods for analyzing whey proteins (Elgar et al, 2000;Ju et al, 1997;. Versatility, short analysis time and high resolution make it one of the main techniques for analyzing protein for the dairy industry (Elgar et al, 2000).…”

Section: High Performance Liquid Chromatography (Hplc)mentioning

confidence: 99%

“…Law and Leaver (2000) used gel permeation FPLC to measure denaturation due to effects of heat and pH utilizing the same basis of loss of solubility at pH 4.6. This method of quantifying the loss pH 4.6 solubility has since been used for measuring denaturation using Kjeldahl (Anand et al, 1998) HPLC (Ju et al, 1997) and Capillary Electrophoresis (Ardö et al, 1999). Extensive review of literature found that this principal of precipitating denatured proteins at pH 4.6 then measuring the total and soluble protein has not been widely used with the BCA assay.…”

Section: Denaturation Characterized By Bca In Wheymentioning

confidence: 99%

See 4 more Smart Citations

A Comparison of Analytical Methods for Quantifying Denatured Whey Proteins and Their Correlation to Solubility

Allen¹

View full text Add to dashboard Cite

A Comparison of Analytical Methods for Quantifying Denatured Whey Proteins and Their Correlation to SolubilityMichelle Doreen AllenProtein structure affects the bioactivity and functionality of whey protein ingredients in food systems. Bioactivity of whey proteins and their derivatives are highly dependent upon primary, secondary and tertiary structure. The degree of denaturation of whey proteins is an important factor for determining how whey protein ingredients will perform in a food system. Several analytical methods have been developed to quantify protein denaturation of whey proteins. The goal of this project was to use a variety of analytical methods to quantify whey protein denaturation and to evaluate the correlation of denaturation to the functionality of whey protein powders.The objective of the first series of experiments was to compare three different analytical methods to measure denaturation of whey proteins in liquid whey obtained by various methods of separation and with varying degrees of heat treatment. A split plot experimental design was used. Raw bovine milk was skimmed and liquid whey was separated from the skim milk at natural pH. Three separation methods: 1) centrifugation,2) membrane filtration and 3) enzyme coagulation, made up the first split plot. Each subplot of liquid whey was then divided into three split plots to receive heat treatment. Heat treatments were no heat, 76°C for fifteen seconds and 85°C for three minutes. Each of the resulting nine treatment combinations was analyzed by 1) polyacrylamide gel electrophoresis, 2) bicinchoninic acid-soluble protein assay and 3) fluorescence spectroscopy to determine the amount of denatured protein in the liquid whey.Fluorescence spectroscopy was found to be the most sensitive and reliable method v for detecting differences in structure due to denaturation, while native polyacrylamide gel electrophoresis was found to be the least sensitive method. The sample which received the centrifugal treatment of isolation with no heat was found to be the most undenatured in structure while the sample which received the enzyme treatment of isolation with high heat was found to be the most denatured in structure.The objective of the second series of experiments was to evaluate the effect of denaturation on whey protein solubility in dried whey protein powders. Solubility is one of the most important functional properties to consider when selecting a whey protein ingredient, especially for beverage systems. Processing parameters are often manipulated in efforts to improve solubility. The protein structures of whey are considered to have an effect on solubility. Specifically, the degree of denaturation of whey proteins is thought to play a role in solubility.In this experimental design, raw bovine milk was skimmed and pasteurized then enzyme-coagulated at natural pH to separate the whey. Liquid whey was then split into three aliquots and each received one of the following treatments: 1) mild heat/ freeze dry, 2) mild heat/spray dry and 3) high ...

show abstract

Section: Gelationmentioning

confidence: 99%

Section: Gelationmentioning

confidence: 99%

Section: High Performance Liquid Chromatography (Hplc)mentioning

confidence: 99%

Section: High Performance Liquid Chromatography (Hplc)mentioning

confidence: 99%

Section: Denaturation Characterized By Bca In Wheymentioning

confidence: 99%

See 3 more Smart Citations

A Comparison of Analytical Methods for Quantifying Denatured Whey Proteins and Their Correlation to Solubility

Allen¹

View full text Add to dashboard Cite

show abstract

Nonthermal gelation of whey proteins induced by organic acids

Queirós

Lopes‐da‐Silva

2017

J of Applied Polymer Sci

View full text Add to dashboard Cite

Gelation of native whey proteins induced by organic acids at ambient temperature was investigated by fundamental small‐deformation oscillatory rheology. Gelling capability, gelation time, and final viscoelastic properties of the gel were dependent on type of acid, protein and acid concentrations, and pH value. Increasing organic acid concentration or increasing the pH (below pI) resulted in lower gelation times and higher gel modulus values. Differential scanning calorimetry demonstrated that the presence of acetic acid significantly reduced denaturation temperature and enthalpy implying a destabilization effect of the protein structure against thermal unfolding, contrarily to what was observed in the presence of HCl at similar pH values. The gelling ability and the denaturing effectiveness of the acids increase with increasing chain length of the alkyl chain, thus suggesting an important contribution of hydrophobic effects promoting denaturation and fostering the establishment of new interactions between the proteins leading to a nonthermal gelation process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45134.

show abstract

Nanotubular structures developed from whey‐based α‐lactalbumin fractions for food applications

Tarhan

Harsa

2014

Biotechnology Progress

View full text Add to dashboard Cite

Whey proteins have high nutritional value providing use in dietary purposes and improvement of technological properties in processed foods. Functionality of the whey-based a-lactalbumin (a-La) may be increased when assembled in the form of nanotubes, promising novel potential applications subject to investigation. The purpose of this study was to extract highly pure a-La from whey protein isolate (WPI) and whey powder (WP) and to construct protein nanotubes from them for industrial applications. For protein fractionation, WPI was directly fed to chromatography, however, WP was first subjected to membrane filtration and the retentate fraction, whey protein concentrate (WPC), was obtained and then used for chromatographic separation. a-La and, additionally b-Lg, were purified at the same batches with the purities in the range of 95%-99%. After enzymatic hydrolysis, WPI-based a-La produced chain-like and long nanotubules with 20 nm width while WPC-based a-La produced thinner, miscellaneous, and fibril-like nanostructures by self-assembly. Raman and FT-IR spectroscopies revealed that a-La fractions, obtained from both sources and the nanostructures, developed using both fractions have some structural differences due to conformation of secondary structure elements. Nanotube formation induced gelation and nanotubular gel network entrapped a colorant uniformly with a transparent appearance. Dairy-based a-La protein nanotubules could be served as alternative gelling agents and the carriers of natural colorants in various food processes.

show abstract

Enzyme-induced gelation of whey proteins: Effect of protein denaturation

Cited by 41 publications

References 27 publications

A Comparison of Analytical Methods for Quantifying Denatured Whey Proteins and Their Correlation to Solubility

A Comparison of Analytical Methods for Quantifying Denatured Whey Proteins and Their Correlation to Solubility

Nonthermal gelation of whey proteins induced by organic acids

Nanotubular structures developed from whey‐based α‐lactalbumin fractions for food applications

Contact Info

Product

Resources

About