产蛋白酶乳酸菌发酵乳清蛋白产支链氨基酸的研究

Study on the production of branched amino acid from whey protein fermented by protease-producing Lactic acid bacteria

研究了一株产蛋白酶的德氏乳杆菌乳亚种(Lactobacillus delbrueckii subsp. lactis)815的高密度发酵条件,确定果糖为最佳碳源、牛肉浸粉和大豆蛋白胨为最佳氮源、发酵温度37 ℃、pH值恒定为5.5、通氮气。在该条件下,菌悬液活菌数为2.63×109 cfu/mL,冷冻干燥后菌粉活菌数为2.93×109 cfu/mL。以LB815菌株发酵乳清蛋白,并研究支链氨基酸(branched amino acid,BCAA)随发酵时间的变化情况。结果显示,BCAA在发酵5 h后开始积累,并在26 h含量达到最大值312.55 mg/kg,随后缓慢减少。以高产蛋白酶的乳酸菌菌株发酵乳清蛋白制备富含BCAA的乳清蛋白发酵液,可应用于运动型的发酵乳制品中,提高产品附加值。

We studied the high density fermentation conditions of a protease-producing strain , Lactobacillus delbrueckii subsp. lactis 815, and the result showed that fructose is the best carbon source, beef powder and soy peptone are the best nitrogen source, 37 ℃ is the best fermentation temperature, 5.5 is the best pH constant, with the nitrogen. In this condition, the live bacteria number in the bacterium suspension is 2.63×10^9 cfu/mL and in the freeze drying powder is 2.93×10^9 cfu/mL. Fermented by the strain of LB815, the production of branched chain amino acids (BCAA) in whey protein was determined. After 5 h, BCAA began to accumulate, and the content in 26 h reached a maximum of 312.55 mg/kg, then slowly decreased. The whey protein fermented by high-yield protease strain of Lactic acid bacteria enriched BCAA can be applied to sport-related dairy products with high added value.