Physiochemical properties, volatile compounds and consumer acceptance of novel ultra-high temperature milk during storage

Abstract

Ultra-high temperature (UHT) treatment, achieved through direct heating (D-UHT) and indirect heating (ID-UHT), imparts a long shelf-life to milk, allowing for non-refrigerated distribution. This study investigates the impact of a novel D-UHT method (155 °C, 0.5 s) on milk properties, volatile compounds, and consumer acceptance, contrasting it with traditional ID-UHT. Compared to ID-UHT, D-UHT milk showed smaller particle size (0.63–0.65 μm) and reduced whey protein denaturation (43.11–61.54 %). No statistically significant difference in consumer overall liking scores was observed between D-UHT and ID-UHT milk samples (from 5.3 to 5.9; P > 0.05). Emoji-check-all-that-apply analysis revealed a more positive attitude towards D-UHT milk before 1-month storage. Identification of 36 volatile compounds, including 18 aroma-active compounds, in the milk samples facilitated characterization through principal component analysis. The profile of D-UHT milk after a 1-month storage period closely resembled that of raw milk. Our findings suggest that novel D-UHT milk may offer enhanced nutrition and consumer acceptance within the first month, attributed to lower heat exposure and a volatile compound profile resembling raw milk.