Abstract

Microscopy was applied to explore changes in fat globules and gas chromatography was used to determine the fatty acid distribution in different lipid classes in ultra-high temperature (UHT) milk processed in a pilot plant. Four milk samples were collected at key steps during UHT-milk production. Second-stage homogenisation significantly decreased fat globule size and disrupted the original milk fat globule membrane (MFGM) organisation. Pasteurisation applied before homogenisation increased the adsorption of casein micelles to the newly formed MFGM. The final UHT treatment for 4 s at 137 degrees C exacerbated the damage to MFGM causing disruption of fat globules. Damaged fat globules in UHT milk were more prone to aggregation and entrapment in the protein network compared with fat globules in commercial UHT milk. The significant modifications of milk microstructure and lipid composition suggested processes applied in commercial dairy plants might contribute to destabilisation of UHT milk during shelf life. (C) 2020 Elsevier Ltd. All rights reserved.

Published in

International Dairy Journal
2020, volume: 109, article number: 104741
Publisher: ELSEVIER SCI LTD

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