Document Type
Journal Article
Publication Title
Molecules
Publisher
MDPI
School
School of Science
RAS ID
31279
Funders
Guangzhou Elite Project
Aarhus University
Abstract
One of the conventional ways to produce lactose-hydrolyzed (LH) milk is via the addition of commercial lactases into heat-treated milk in which lactose is hydrolyzed throughout storage. This post-hydrolysis method can induce proteolysis in milk proteins due to protease impurities remaining in commercial lactase preparations. In this work, the interplay between lactose hydrolysis, proteolysis, and glycation was studied in a model system of purified β-casein (β-CN), lactose, and lactases using peptidomic methods. With a lactase presence, the proteolysis of β-CN was found to be increased during storage. The protease side-activities mainly acted on the hydrophobic C-terminus of β-CN at Ala, Pro, Ile, Phe, Leu, Lys, Gln, and Tyr positions, resulting in the formation of peptides, some of which were N-terminal glycated or potentially bitter. The proteolysis in β-CN incubated with a lactase was shown to act as a kind of “pre-digestion”, thus increasing the subsequent in vitro digestibility of β-CN and drastically changing the peptide profiles of the in vitro digests. This model study provides a better understanding of how the residual proteases in commercial lactase preparations affect the quality and nutritional aspects of β-CN itself and could be related to its behavior in LH milk.
DOI
10.3390/molecules24162876
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
Zhao, D., Le, T. T., Larsen, L. B., Nian, Y., Wang, C., Li, C., & Zhou, G. (2019). Interplay between residual protease activity in commercial lactases and the subsequent digestibility of β-casein in a model system. Molecules, 24(16).
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