乳酸菌蛋白水解力的测定及研究

试验采用邻苯二甲醛法，对８种乳酸菌共计３７株菌在适宜温度下发酵脱脂复原乳（ＮＦＳ：１１％）产生的游离氨基酸含量进行了测定。结果表明，嗜热乳杆菌（保加利亚乳杆菌、瑞士乳杆菌、嗜酸乳杆菌）的蛋白水解力较高，其游离氨基酸含量可达３０３．８７ｍｇＬ－１（１４７．８５～４６６．５９ｍｇＬ－１）而乳球菌和干酪乳杆菌的蛋白水解力较低，一般为５０ｍｇＬ－１左右，其中保加利亚乳杆菌ＬＢ－１，３－１及瑞士乳杆菌ＬＨ的蛋白水解力最高，适宜于制作干酪。蛋白水解力随着发酵酸度及菌体生物量的增加而呈上升趋势，但乳球菌及干酪乳杆菌的变化不大。另外，对保加利亚乳杆菌ＬＢ－１与嗜热链球菌ＳＴ－１发酵乳样的氨基酸分析表明，天冬门氨酸、丝氨酸、谷氨酸、甘氨酸、异亮氨酸、亮氨酸、赖氨酸、组氨酸、酪氨酸、精氨酸等是嗜热链球菌生长需要的氨基酸，均可由保加利亚乳杆菌分解乳蛋白提供。

STUDIES ON THE PROTEOLYTIC ACTIVITY OF VARIOUS LACTIC ACID BACTERIA FERMENTED MILK

OPA agents spectrophotometry was a better method to evaluate the proteolysis ability of lactic acid bacteria. Proteolysis of lactobacillus thermophilus (LB. LH. LA) was higher than that of lactococcus, streptococcus thermophilus and lactobacillus casei. The average concentration of lactobacillus. thermophilus L Casei, lactococcus were 303.87mgL-1,85.51mgL-1, 58318mgL-1,respectively. The proteolysis ability of Lactobacillus thermophilus(LB. LA. LH)have a risen tendence as their acidity and biomasss increasing. But, the proteolysis of LC and lactococcus havent changed during its fermentation . Higher proteolysis ability of LB-1 LH and 3-1 strains can be used in processing of cheese.Streptococcus thermophilus require amino acids including Asp. Aer, Glu, Gly Ile. Leu,Lys, His. Tyr and Arg, which produced by lactobacillus bulgaricus.