Abstract:Milk sterilization is essential in milk processing. Different sterilization methods can change the flavour and physico-chemical properties of milk, thus affecting the shelf-life of milk products and consumer preferences. In this study, the physicochemical properties, volatile compounds, and sensory evaluation of raw milk, high-temperature short-time pasteurized milk (HTST milk), and milk treated by infusion technology (INF milk) during storage at 4 ℃ were studied. The study of physico-chemical properties of INF milk showed that its pH decreased significantly, while the particle size and viscosity increased significantly after 30 days storage (P<0.05). In addition, the key flavour compounds in three groups of milk samples were qualitatively and semi-quantitatively analyzed by headspace solid phase extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-olfactory measurement (GC-O). There were 50 volatile compounds detected in milk by HS-SPME-GC-MS, of which 24 could be also detected by GC-O. Among them, some ketones, alcohols, lactones were only measured in INF milk, such as 2-nonanone, 2-butanol, and δ-dodecanol. Moreover, the sweetness and milky flavour of INF milk in sensory evaluation were better than those of HTST milk, however, the aftertaste of INF milk was also heavier. Both HTST milk and INF milk had light cooking flavour. The total concentration of aldehyde in milk was strongly correlated with the sensory evaluation. The results could provide a scientific basis for the rational storage of raw milk, HTST milk, and INF milk.
