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Glycation of Whey Protein To Provide Steric Hindrance against Thermal Aggregation

Liu, Gang, Zhong, Qixin
Journal of agricultural and food chemistry 2012 v.60 no.38 pp. 9754-9762
acidity, analytical methods, calcium chloride, denaturation, dispersibility, dispersions, glycation, heat treatment, ionic strength, isoelectric point, maltodextrins, pH, sodium chloride, temperature, whey, whey protein
Thermal processing is required for a variety of products and remains a problem for whey proteins that undergo denaturation and aggregation above the denaturation temperature. This causes challenges to maintain clarity and dispersibility of protein dispersions, particularly at acidity near the isoelectric point of the protein and increased ionic strength. This work reports for the first time that glycation of whey protein with a sufficient number of maltodextrins prevented protein aggregation before and after heating at 88 °C for 2 min at pH 3.0–7.0 and 0–150 mM NaCl or CaCl₂. The mechanism of maintaining protein dispersion clarity during heating was illustrated by several complementary analytical techniques that elucidated primary, secondary, and tertiary structures, as well as thermal denaturation and surface charge properties of glycated whey proteins. Steric hindrance was concluded to be the major mechanism responsible for transparent dispersions with protein structures smaller than 12 nm after heating.