关键词: 乳酸菌；自溶度；氨肽酶；质构；流变性质

Abstract: In this paper, seven representative strains of lactic acid bacteria isolated from cheese samples collected from Xinjiang, Yunnan and Tibet were selected for evaluation of their acid-producing ability, viscosity-producing ability, degree of autolysis and aminopeptidase activity. The texture and rheological characteristics of fresh cheese produced using each strain were analyzed. The results showed that both Lactococcus lactis E11 and C44 were advantageous in the four characteristics. In terms of acid production, ΔpH (between 0 and 24 h) was high, the viscosity was moderate, and they were highly autolytic and displayed high aminopeptidase activity. Correlation analysis demonstrated that for fresh cheese made with single strains, moisture content had a highly significantly negative correlation with hardness but was extremely significantly positively correlated with adhesivenes. In addition, pH, protein content, and fat content also had a significantly positive correlation with texture. In terms of texture, there was a significant difference among the cheeses evaluated (P < 0.05). The dynamic rheological analysis showed that elastic properties were dominant for all cheeses (G’ > G”). The cheeses made with E11 and C44 exhibited hardness, cohesiveness, and elasticity closer to those of the control group. Collectively, these results proved that L. lactis E11 and C44 could be selected as starter culture for in the perparation of fresh cheese, and mixed starter cultures of these strains and others may be available in the future.

Key words: lactic acid bacteria; autolysis; aminopeptidase; texture; rheological properties