Effect of pH on the Thermal Denaturation of Whey Proteins in Milk

The effect of pH on thermal denaturation of four main whey protein fractions in skim milk was examined by gel permeation FPLC. On heating skim milk at 80 °C for 0.5−20.0 min over the pH range 5.2−8.8, the extent of denaturation, based on loss of solubility at pH 4.6, increased with heating time and...

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Bibliographic Details
Published in:Journal of agricultural and food chemistry 2000-03, Vol.48 (3), p.672-679
Main Authors: Law, Andrew J. R, Leaver, Jeffrey
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Chromatography, Liquid
Food industries
Fundamental and applied biological sciences. Psychology
Hot Temperature
Humans
Hydrogen-Ion Concentration
Milk - chemistry
Milk and cheese industries. Ice creams
Milk Proteins - chemistry
Protein Denaturation
Whey Proteins
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Summary:The effect of pH on thermal denaturation of four main whey protein fractions in skim milk was examined by gel permeation FPLC. On heating skim milk at 80 °C for 0.5−20.0 min over the pH range 5.2−8.8, the extent of denaturation, based on loss of solubility at pH 4.6, increased with heating time and was usually in the order immunoglobulins > serum albumin/lactoferrin > β-lactoglobulin > α-lactalbumin. Rates of denaturation of the immunoglobulins and the serum albumin/lactoferrin fraction were highest at the lower end of this pH range, whereas those of β-lactoglobulin and α-lactalbumin increased over most of the pH range. The effects of pH, addition of Ca, and reduction of disulfide bonds on the rates of the unfolding and aggregation stages of denaturation are discussed. Keywords: Whey protein; denaturation; aggregation; pH
ISSN:0021-8561
1520-5118
DOI:10.1021/jf981302b