Study on Amino Acid Metabolism Characteristics of Litchi Juice-Soybean Protein Fermented by Eight Lactic Acid Bacteria

This study was aim to explore the different amino acid metabolism characteristics of Litchi juice-soybean protein fermented by eight lactic acid bacteria. Thelitchi juice-soybean protein was fermented by eight different lactic acid bacteria at 37 ℃ for 18 h. The number of lactic acid bacteria and the content of amino acid in the ferementation broth were detected. The results showed that 17 kinds of amino acids were measured.The total contents ofamino acid was decreased from 582.79 mg/100 g to 427.97 mg/100 g after fermentation.The total amino acids of different lactic acid bacteria were significantly different,e.g. Lactobacillus paracei FJAT-13741(365.95 mg/100 g)<Streptococcus thermophilus FJAT-43774(369.36 mg/100 g)<L.fermentum FJAT-13771(411.03 mg/100 g)<L. plantarum FJAT-13773(417.54 mg/100 g)<L.breris FJAT-43776(438.14 mg/100 g)<L.rhamnosus FJAT-13807(462.38 mg/100 g)<L. acidophilus FJAT-13772(477.65 mg/100 g)<L.delbrueckii FJAT-43773(481.52 mg/100 g). Cluster analysis results showed that the amino acid metabolism characteristics of 8 lactic acid bacteria were divided into 3 groups,containing one amino acid in the high content group,five amino acids in the medium content group,and eleven amino acids in the low content group;the eight lactic acid bacteria could be divied into three groups containing the high content group with three lactic acid bacteria,the middle content group with three lactic acid bacteria,and the low content group with two lactic acid bacteria. Amino acid metabolic characteristic index(AAMCI)was constructed,which represented the ratio of functional amino acids to total amino acids. The highest ratio of AAMCI was L.delbrueckii FJAT-43773(54.32%),and the lowest one was S. thermophilus FJAT-43774(47.82%).This study would provide information for the screening of fermentation strains for the lychee lactic acid bacteria beverages.