Dingxi Teachers College, Dingxi, 743000, China.
J Food Sci. 2014 Feb;79(2):M214-21. doi: 10.1111/1750-3841.12340. Epub 2014 Jan 21.
Miniature Cheddar-type cheeses were produced using microbial rennet from Bacillus amyloliquefaciens (milk-clotting enzyme [MCE]) or calf rennet (CAR). With the exception of pH, there were no significant differences in gross composition between MCE-cheese (MCE-C) and CAR-cheese (CAR-C). The pH value of CAR-C was significantly higher than that of MCE-C at 40 and 60 d of ripening. The total nitrogen content of the pH 4.6-soluble fraction obtained from MCE-C was higher than that obtained from CAR-C. However, nitrogen content of the 12% TCA-soluble fraction was similar between CAR-C and MCE-C. The extent of α(s1)-casein and β-casein hydrolysis, measured by urea-PAGE, was similar in both cheese samples. The hydrolysis of β-casein was lower than that of α(s1)-casein. Different reverse phase-high-performance liquid chromatography peptide profiles of ethanol-soluble and ethanol-insoluble fractions were obtained from CAR-C and MCE-C. The peptide content in the 2 cheese samples increased throughout ripening; the ratio of hydrophobic to hydrophilic peptides was lower in MCE-C than in CAR-C. Compared with CAR-C, MCE-C was softer as a result of higher protein hydrolysis. Microbial rennet from B. amyloliquefaciens contributed to higher proteolytic rates, which reduced ripening time.
干酪采用解淀粉芽孢杆菌微生物凝乳酶（凝乳酶[MCE]）或小牛凝乳酶（CAR）制作而成。除了 pH 值外，MCE 奶酪（MCE-C）和 CAR 奶酪（CAR-C）的总组成没有显著差异。成熟 40 和 60 天时，CAR-C 的 pH 值明显高于 MCE-C。从 MCE-C 获得的 pH4.6 可溶部分的总氮含量高于从 CAR-C 获得的氮含量。然而，12%TCA 可溶部分的氮含量在 CAR-C 和 MCE-C 之间相似。通过尿素-PAGE 测量的 α(s1)-酪蛋白和 β-酪蛋白水解程度在两种奶酪样品中相似。β-酪蛋白的水解程度低于 α(s1)-酪蛋白。从 CAR-C 和 MCE-C 获得的乙醇可溶和乙醇不溶部分的反相高效液相色谱肽图谱不同。两种奶酪样品的肽含量在成熟过程中均增加；与 CAR-C 相比，MCE-C 中疏水性肽与亲水性肽的比例较低。与 CAR-C 相比，MCE-C 的质地更柔软，因为其蛋白质水解程度更高。解淀粉芽孢杆菌的微生物凝乳酶促进了更高的蛋白水解率，从而缩短了成熟时间。
