The Effect of the Ratio of Gamma Aminobutyric Acid-Producing Saccharomyces cerevisiae DL6-20 and Kluyveromyces marxianus B13-5 Addition on Cheese Quality.

ABSTRACT

Kazakh cheese is a traditional dairy product in Xinjiang, China. The function and potential probiotic characteristics of Saccharomyces cerevisiae DL6-20 and Kluyveromyces marxianus B13-5 in Kazakh cheese and its contribution to cheese fermentation was studied. In this study, the effect of the addition ratio of gamma aminobutyric acid (GABA)-producing S. cerevisiae DL6-20 and K. marxianus B13-5 on cheese quality was investigated. Cheeses were prepared by fermentations with a total of six treatments comercial culture alone as control (CS), a combination with one yeast, either; K. marxianus B13-5 (CSM); S. cerevisiae DL6-20 (CSS); and three different proportions of this two yeasts (CSMCSS 11, 12, 21). We measured the GABA content of cheese, as well as basic physical and chemical indicators, microbial content, free amino acid (FAA) content, texture, and flavor compound content. The total FAA content of mixed bacteria fermentation was higher than that of the single bacteria alone. The GABA content CSMCSS 12 GABA content was 0.114 g/100 g, CSMCSS 21 GABA content was 0.12 g/100 g, CSMCSS11 content of GABA produced in the late ripening period of cheese was the highest, reaching 0.189 g/100 g and the number of LAB and yeasts in CSMCSS 11 was higher than that of other cheeses. The mixed-strain fermentation generally produced cheeses with a higher protein content than that of the single-strain fermentation in the late stage of the maturation process, especially the protein content of CSMCSS 11 during the ripening period, when the protein content was highest at day 50. CSMCSS 11 had a low moisture content, making it easy to store. With the exception of water and protein content, there is no significant difference in other physical and chemical indicators. CSMCSS 11 contributed to the formation of cheese texture. In addition, multivariate statistical analysis indicated that mixed-strain fermentation was beneficial to the production of cheese aroma, with the aroma production performance of CSMCSS 12 and CSMCSS 21 found to be better than that of CSM CSS 11.