Preparation of soluble dietary fiber in almond skin using enzymatic method in coordination with ultrasonic wave and study on physicochemical properties

Flat almond skin in western Liaoning region as material to extract water soluble dietary fiber (SDF) by enzymatic method in coordination with ultrasonic wave.Parameters of ultrasonic-assisted extraction were optimized.The liquid-material ratio, composite cellulase addition and extraction time were selected as factors to carry out the single factor experiment.The response surface method was applied to optimize technical parameters of SDF preparation using liquid-material ratio, enzyme addition, enzymolysis time as variables, and SDF extraction rate as response value.The results showed that parameters of ultrasonic-assisted extraction were power 500W, treatment time 15min.The optimum parameters were liquid-material ratio 17:1, cellulase addition 1.8%, extraction time 3.5h at temperature 55℃.Under these conditions, the SDF extraction rate reached to 13.27%.Water-holding capacity and swelling property of SDF of almond skin were 8.31g/g and 6.48mL/g.The SDF of almond skin has excellent physicochemical properties。