Thermal Properties of Yak α-Lactalbumin and β-Lactoglobulin: a DSC Study
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Date
2017-09-18
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Springer
Abstract
A differential scanning calorimetry (DSC) method was used to investigate the denaturation temperature of yak α-lactalbumin (α-La), β-lactoglobulin (β-Lg), and a mixture of two proteins and the thermal properties of α-La and β-Lg in the presence of glucose, lactose, sucrose, NaCl, CaCl2, and at various pH (4.0–10.0). The denaturation temperature (T d) of α-La increased from 52.1 °C in the absence of β-Lg to 53.9 °C in the presence of β-Lg, while the T d of β-Lg decreased from 81.4 °C in the absence of α-La to 79.9 °C in the presence of α-La. α-La was thermal stable in the range of pH 4.0–10.0, while β-Lg was more thermal stable in acidic pH than in alkaline pH. Sugars, Na+, and Ca2+ influenced the stabilization of the two proteins against thermal denaturation with greatly influenced for β-Lg. α-La kept reversibility in the presence of sugars, NaCl, CaCl2, and over a wide pH range (4.0–10.0), with most of the reversibility values being greater than 90%. In contrast, β-Lg was completely irreversible whether in its native state or in the presence of the additives.
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Keywords
Yak milk, α-Lactalbumin, β-Lactoglobulin, DSC differential scanning calorimetry, Thermal denaturation