Abstract: Highland barley bran is a rich source of dietary fiber. However, it gives a rough feeling in the mouth so that only less than 10% of highland barley bran is currently applied in the food industry. Ultra-fine grinding is an emerging technology that can effectively enhance the utilization value of food raw materials. In this study, jet impact milling was used to prepare highland barley bran of four different average particle sizes, namely coarse highland barley bran (CHB) and medium highland barley bran (MHB), fine highland barley bran (FHB) and ultrafine highland barley bran (UHB). Their dietary fiber composition, structure, physicochemical properties and sensory quality were studied. The results showed that reducing the particle size of highland barley bran had only little effect its dietary fiber content and composition. However, the water holding capacity and fat absorption capacity of highland barley bran treated by jet impact milling declined with decreasing particle size, and the water swelling capacity rose initially and then dropped. The structure of dietary fiber in UHB was damaged, and cracks were observed on the fiber surface. On the other hand, jet impact milling treatment enhanced the functional characteristics, and improve the sensory quality and reconstitution characteristics of UHB. Therefore, jet impact milling treatment can improve the rough mouthfeel and agglomeration degree of highland barley bran by changing the particle size and physicochemical properties and further improve the stability of reconstituted highland barley bran products.

Key words: highland barley bran; jet impact milling; particle size; functional properties; reconstitution stability