产胞外多糖乳酸菌的鉴定及发酵性能研究

Study on identification and ferment character of high exopolysaccharide-producing lactic acid bacteria strains

筛选到两株分离自开菲尔粒的高产胞外多糖乳酸菌菌株,采用硫酸苯酚法测定其胞外多糖产量分别为112.23和94.50mg/L,菌种鉴定结果表明,该两株菌分别为德氏乳杆菌德氏亚种和乳酸乳球菌乳脂亚种。研究菌株发酵乳的乳清析出、黏度、回复性等重要发酵性能指标,结果表明,产胞外多糖的乳酸菌与不产胞外多糖的乳酸菌相比可以增加发酵乳的黏度,减少乳清析出,使发酵乳具有较好的回复性。

Two strains with high exopolysaccharide-producing capacity were isolated from kefir grain.The yields of EPS-producing for two strains were 111.21 mg/L and 91.20 mg/L determining by H2SO4 phenol method.The two strains were identified,one strain was Lactobacillus delbrueckii subsp.delbrueckii and the other was lactococcus lactis subsp.cremoris.Comparing with the strains without exopolysaccharide activity,the EPS-producing strain could increase the viscosity of the fermented milk,decrease the syneresis,and confer the end product with high recovery by studying the influence of strains on the quality of fermented milk.