Data_Sheet_1_Investigation of the Lactic Acid Bacteria in Kazak Cheese and Their Contributions to Cheese Fermentation.docx

Kazak cheese is a traditional dairy product fermented by lactic acid bacteria (LAB) in Xinjiang. To investigate the LAB in Kazak cheese and their contributions to cheese fermentation, four representative LAB, Streptococcus thermophilus B8, Lactobacillus helveticus B6, Weissella confusa B14, and Lactobacillus rhamnosus B10, were isolated from Kazak cheese and subsequently used to ferment cheeses, which were named StC, LhC, WcC, and LrC, respectively. The result showed that most of the physical and chemical indicators had no significant difference, except for moisture and fat. W. confusa B14 was beneficial to the production of amino acids, whereas S. thermophilus B8 promoted the formation of organic acids and contributed to formation ideal texture property. Furthermore, the four cheeses all possessed a strong fruity aroma, with brandy, sweet, herbaceous, pungent, and fatty aromas being the most prominent in WcC. This is because L. helveticus B6 produced a high concentration of hexanal, nonanal, octanal, 3-methylbutanoic acid, ethyl acetate, ethyl butanoate, isoamyl acetate, and ethyl hexanoate in LhC. Research on the fermentation mechanism of LAB in cheese will provide a theoretical basis for the quality control and industrial production of Kazak cheese.

哈萨克族奶酪是新疆地区由乳酸菌（Lactic Acid Bacteria，简称LAB）发酵制成的传统乳制品。为探究哈萨克族奶酪中的乳酸菌及其对奶酪发酵的贡献，研究人员从哈萨克族奶酪中分离得到4株代表性乳酸菌：嗜热链球菌（Streptococcus thermophilus）B8、瑞士乳杆菌（Lactobacillus helveticus）B6、混淆魏斯氏菌（Weissella confusa）B14与鼠李糖乳杆菌（Lactobacillus rhamnosus）B10，并以其分别发酵制作奶酪，对应命名为StC、LhC、WcC与LrC。研究结果显示，除水分与脂肪含量外，多数理化指标无显著差异。其中混淆魏斯氏菌B14有助于氨基酸的生成，而嗜热链球菌B8则可促进有机酸的形成，并有助于构建理想的质地特性。此外，四款发酵奶酪均具有浓郁果香，其中WcC的白兰地香、甜香、草本香、刺激性香气与脂香最为突出。这是由于瑞士乳杆菌B6在LhC中可高浓度生成己醛、壬醛、辛醛、3-甲基丁酸、乙酸乙酯、丁酸乙酯、乙酸异戊酯与己酸乙酯。针对奶酪中乳酸菌发酵机制的研究，将为哈萨克族奶酪的品质管控与工业化生产提供理论依据。