Optimization of compound osmsticum formula and its effects on the vaccum freeze-drying of mung bean sprouts

The pretreatment effects of compound somsticum on the vaccum freeze-drying of mung bean sprouts were studied using quadratic orthogonal regressive experiments combined with three factors. Based on the result, the regressive equation was established, and the compound osmsticum formula was optimized and verified. Meanwhile, the quality indexes of the freeze-dried products were investigated with the optimized compound osmsticum, and the energy-saving effect was analyzed. The changes in epidermal cell architecture of the products were also examined under microscope. Results show that the optimum ratio of the compound osmsticum formula is maltodextrin:CMC:starch=21.2%:0.16%:2.5%. The pretreatment with the optimized compound osmsticum greatly improve the freeze-drying effects of mung bean sprouts. Compared to the untreated product, the comprehensive indexes of yield and quality are improved by 18.3%, the retention of vitamin C raises by 25.9%, the drying time is shortened by 36.9%, the electric energy is saved by 19.9%, and the safe humidity of the product raised up to 10.0%. Under the microscope, the epidermal cell architecture is not destroyed.