Abstract

In the ultra-high temperature (UHT) process, milk is subject to temperatures above 135 degrees C for few seconds giving a product with a shelf-life of several months. The raw milk quality, UHT process and storage conditions affect the stability. In this study, the stability of UHT milk produced in an indirect system was evaluated by studying changes in taste, colour, fat separation, fat adhesion to the package, sedimentation, gelation, heat coagulation time, pH and ethanol stability during storage for up to one year at different temperatures. UHT milk stored at 4 and 20 degrees C had the longest shelf-life of 34-36 weeks, limited by sediment formation. Storage a 30 and 37 degrees C considerably decreased the shelf-life of UHT milk to 16-20 weeks, whereby changes in sediment formation, taste and colour were the limiting factors. Our results suggest that the changes observed at the different storage temperatures can be explained by different known mechanisms.

Keywords

Food technology; Food safety; UHT milk; Sensory evaluation; Off-flavour; Sedimentation; Colour; Food acceptance; Food quality; Food science; Food storage; Shelf life of foods

Published in

Heliyon
2019, volume: 5, number: 9, article number: e02431

Authors' information