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Effect of pH on the formation of serum heat‐induced protein aggregates in heated yak milk
Author(s) -
Xu Weiyi,
He Shenghua,
Ma Ying,
Zhang Yixin,
Li Qiming,
Wang Lifeng,
Wang Rongchun
Publication year - 2015
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/1471-0307.12218
Subject(s) - chemistry , casein , chromatography , protein aggregation , size exclusion chromatography , whey protein , beta lactoglobulin , heat stability , biochemistry , enzyme , materials science , composite material
Serum heat‐induced protein aggregates at various pH levels were isolated from heated yak milk by size‐exclusion fast protein liquid chromatography. Analysis by reversed‐phase high‐performance liquid chromatography showed that β‐lactoglobulin and κ‐casein were the two main proteins in these aggregates. The amount of serum heat‐induced protein aggregates increased from pH 6.6 to 7.4, whereas the content of β‐lactoglobulin in aggregates decreased from 61.9% at pH 6.6 to 50.4% at pH 7.2, and then increased to 51.3% at pH 7.4. The content of κ‐casein, αs 1 ‐casein and β‐casein increased from pH 6.6 to pH 7.4. These results show that serum heat‐induced protein aggregates are pH dependent.