To explore the physicochemical characters of barley grass, ultra-micro-crushing (UMC) technology combined with air drying or freeze drying was carried out. After barley grass was air-dried at 70°C or freeze-dried at 15°C, it was grinded for 30, 60, 90, and 120 min using UMC, respectively. After combined processing, moisture content, particle size, odor, color, microstructure, water and oil-holding capacity, the content of flavonoid and chlorophyll, water activity, and sensory qualities were determined. The particle size of barley grass powder decreased, and lightness value was increased; water and oil-holding capacity decreased significantly (p ≤ .05), whereas swelling and dissolving capacity increased in the processed grass powder. On the other hand, the total flavonoid content increased significantly (p ≤ .05). Barley grass odor features sulfide aroma, and its microstructure demonstrates lamellar morphology with some fewer fragmented pieces. The results suggested combined UMC at 90-120 min will be suitable for processing barley grass powder.
Keywords: barley grass; drying methods; physicochemical properties; sensory quality; ultra‐micro‐crushing.
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