Abstract：
The aim of this research was to find out the effect of different combinations of starter and non-starter cultures on the proteolysis of Castellano cheese during ripening. Four cheese batches were prepared, each containing autochthonous lactobacilli and or Leuconostoc, and were compared with each other and with a control batch, that used only a commercial starter. To achieve this, nitrogen fractions (pH 4.4-soluble nitrogen and 12 % trichloroacetic acid soluble nitrogen, polypeptide nitrogen and casein nitrogen), levels of free amino acids and biogenic amines were assessed. Texture and microstructure of cheeses were also evaluated. Significant differences in nitrogen fractions were observed between batches at different stages of ripening. The free amino acid content increased throughout the cheese ripening process, with a more significant increase occurring after the first 30 days. Cheeses containing non-starter lactic acid bacteria exhibited the highest values at the end of the ripening period. Among the main amino acids, GABA was particularly abundant, especially in three of the cheese batches at the end of ripening. The autochthonous lactic acid bacteria were previously selected as non-producers of biogenic amines and this resulted in the absence of these compounds in the cheeses. Analysis of the microstructure of the cheese reflected the impact of proteolysis. Additionally, the texture profile analysis demonstrated that the cheese\'s hardness intensified as the ripening period progressed. The inclusion of autochthonous non-starter lactic acid bacteria in Castellano cheese production accelerated the proteolysis process, increasing significantly the free amino acids levels and improving the sensory quality of the cheeses.
摘要：
这项研究的目的是找出发酵剂和非发酵剂培养物的不同组合对Castellano奶酪成熟过程中蛋白水解的影响。准备了四批奶酪，每种都含有自生乳杆菌和/或明串珠菌，并与对照批次进行了比较，只使用了商业启动器。为了实现这一点，氮组分（pH4.4可溶性氮和12％三氯乙酸可溶性氮，多肽氮和酪蛋白氮），评估游离氨基酸和生物胺的水平。还评估了奶酪的质地和微观结构。在不同成熟阶段的批次之间观察到氮分数的显着差异。在整个奶酪成熟过程中，游离氨基酸含量增加，在前30天后出现更显著的增加。含有非发酵剂乳酸菌的奶酪在成熟期结束时表现出最高值。在主要的氨基酸中，GABA特别丰富，尤其是在成熟结束时的三个奶酪批次中。先前选择了自体乳酸菌作为生物胺的非生产者，这导致奶酪中不存在这些化合物。对干酪微观结构的分析反映了蛋白水解的影响。此外,质构轮廓分析表明，奶酪的硬度随着成熟期的增加而增强。在Castellano奶酪生产中加入自生非发酵剂乳酸菌加速了蛋白水解过程，显著提高游离氨基酸水平，提高奶酪的感官品质。
