桑 叶发 酵 工 艺 优化 及 营 养价 值 评 价

In order to improve the nutritional value of mulberry leaves, the optimization of technology of mulberry leaf fermentation was studied. The contents of crude protein and tannin in fermented mulberry leaves were used as indexes, the optimum fermentation conditions of fermented mulberry leaves were identified by an L₉(3⁴) orthogonal experiment with mulberry leaves to bran mass ratio, strain combination, inoculation amount and fermentation time. The verification experiment and comparison experiment were carried out according to the results of orthogonal experiment. The results showed as follows: 1) the optimal combination of orthogonal experiment was as follows, the mulberry leaves to bran mass ratio was 9∶1, the strain combination was Pediococcus cellicola+Bacillus licheniformis, the inoculation amount was 2%, and the fermentation time was 4 days. 2) The verification experiment showed that the crude protein and tannin contents of the optimized combination fermentation of mulberry leaves were 26.18% and 4.73 g/kg respectively, which were better than the optimal values in the orthogonal experiment table. 3) The comparison experiment showed that compared with unfermented mulberry leaves, the contents of crude protein, ether extract, ash and phosphorus in fermented mulberry leaves were significantly increased (P<0.05), and the contents of tannin, neutral detergent fiber and carbohydrate and pH were significantly decreased (P<0.05). Compared with unfermented mulberry leaves, the contents of arginine, serine, glutamic acid, aspartic acid, total non-essential amino acids and total amino acids of fermented mulberry leaves were significantly decreased (P<0.05), while the alanine content, total essential amino acids/total amino acids and total essential amino acids/total non-essential amino acids were significantly increased (P<0.05). The composition of cystine+methionine, threonine, leucine and tyrosine+phenylalanine of fermented mulberry leaves was significantly higher than that of unfermented mulberry leaves (P<0.05). In conclusion, the optimal condition for fermenting mulberry leaves is as follows, the mulberry leaves to bran mass ratio is 9∶1, the strain combination is Pediococcus cellicola+Bacillus licheniformis, the inoculation amount is 2%, and the fermentation time is 4 days. Fermentation improves the nutritional value of mulberry leaves.