Article,
Impact of hydrolysis method and lactase preparation on proteolysis and glycation in long-term stored lactose-hydrolysed UHT milk
Affiliations
- [1] Aarhus Univ, Dept Food Sci, Agro Food Pk 48, DK-8200 Aarhus, Denmark [NORA names: AU Aarhus University; University; Denmark; Europe, EU; Nordic; OECD];
- [2] CiFOOD Aarhus Univ Ctr Innovat Food Res, Agro Food Pk 48, DK-8200 Aarhus N, Denmark [NORA names: Miscellaneous; Denmark; Europe, EU; Nordic; OECD];
- [3] DSM Firmenich, Alexander Fleminglaan 1, NL-2613 AX Delft, Netherlands [NORA names: Netherlands; Europe, EU; OECD];
- [4] Arla Foods Innovat Ctr, Agro Food Pk 19, DK-8200 Aarhus N, Denmark [NORA names: Arla Foods; Private Research; Denmark; Europe, EU; Nordic; OECD]
Abstract
Shorter shelf-life of lactose-hydrolysed UHT milk (LHM) can be linked to lactase purity both due to unwanted proteolytic activity and Maillard reactions. To study this, pre- and post-hydrolysed milk was added one of three types of lactase enzymes of increasing purity (A, B and C), and stored for up to 1 year at 25 or 35 degrees C. Proteolytic side-activities in post-hydrolysed milk depended on lactase purity, with lactase A causing the highest proteolysis. The lowest proteolytic activity occurred with lactase C in both pre- and post-hydrolysed milk. LHM with lactase A exhibited proteolysis in C-terminal regions of major milk proteins, particularly in post-hydrolysed milk, which also showed endopeptidase activity. Glycation initiated by UHT treatment was higher in pre-hydrolysed milk than in post-hydrolysed milk, but subsequent storage led to similar glycation levels in both. Therefore, using post-hydrolysis with highly purified lactases, proteolytic side-activities can be lowered and glycation can be delayed. (c) 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).