【作者】 董莹；

【导师】 张和平；

【作者基本信息】 内蒙古农业大学 ， 食品科学， 2006， 硕士

【摘要】 探讨原料乳中SCC对契达干酪品质的影响,以期对干酪制作中原料乳的体细胞控制提供理论依据。用SCC分别是5.6, 48.8, 476.1×10万个/mL的原料乳制作契达( cheddar)干酪,得到LSCC、MSCC、HSCC组干酪,对各组干酪成熟过程中蛋白质水解、脂解、滴定酸度、乳酸菌总数、游离钙/总钙、游离磷/总磷、流变学和感官评定等各项指标进行测定。结果显示:1.从干酪真实出品率来看: LSCC组>MSCC组>HSCC组,且在P<0.05水平下差异显著。2.干酪成熟过程中蛋白的水解变化是:成熟的1~180天,WSN/TN与SCC在P<0.01水平下线性相关,相关系数0.4261;成熟的30~180天,NPN/TN与SCC在P<0.05水平下线性相关,相关系数0.3560;Urea-PAGE结果显示,HSCC组干酪与LSCC、MSCC组干酪的酪蛋白水解产物不同。3.干酪成熟过程中脂解结果是:HSCC组干酪的FFA在P<0.05的水平下显著高于LSCC、MSCC组干酪,且FFA与SCC在P<0.0001的水平下正相关,相关系数0.7579。4.干酪成熟过程中滴定酸度与SCC在P<0.001的水平下正相关,相关系数0.4938。5.在干酪成熟的15~30天里,乳酸菌生长旺盛,各组在P<0.05的水平下差异显著,乳酸菌数: LSCC组>MSCC组>HSCC组干酪。6.在成熟过程中游离钙/总钙先增加,后趋于稳定;游离磷/总磷先降低,后趋于稳定。7.干酪成熟过程中,硬度、剪切力与SCC在P<0.01的水平下负相关,相关系数分别为0.5482、1.3977;感官评定结果显示, HSCC组干酪有酸味,且组织状态软而粘。研究结果表明LSCC原料乳的契达干酪在质量和产量上均优于HSCC原料乳干酪。更多还原

【Abstract】 In order to provide theoretical foundation for controlling SCC in raw milk during making cheese, the effect of SCC in raw milk on the quality a during ripening was studied.The milk used for making cheddar cheese was divided in three trials. Each trial had different SCC in milk(LSCC.56,000, MSCC.48,800, HSCC.476,1000). During ripening, proteolysis, lipolysis, titration acidity, the number of lactic acid bacteria, free calcium to total calcium, free phosphorus to total phosphorus, rheology, organoleptic evalution of all three cheeses were analyzed.The result are:1. The relationship between increasing milk scc and decreasing actual cheese yield is linear, and there is significant difference among three cheeses(p<0.05).2. There is a linear relationship between water soluble nitrogen (WSN): total nitrogen ratio of cheese and scc (p<0.01)before 180d of ripening, correlation coefficients(R) is 0.4261. Non-protein nitrogen (NPN): total nitrogen ratio of cheese correlated to scc(p<0.05) between 30d and 180d of ripening. The result of Urea-PAGE shows there is difference in proteolysis products of caseins among three cheeses.3. The content of free fatty acid of cheese of HSCC was significant higher than that of cheese of MSCC and LSCC(p<0.05)during ripening, and the content of free fatty acid of cheese positively correlated to scc(p<0.0001), R is 0.7579.4. Titration acidity of cheese positively correlated to scc (p<0.01)during ripening, R is 0.4938.5. The number of lactic acid bacteria increased markedly between 15 and 30 d of ripening. The relationship between increasing milk scc and decreasing number of lactic acid bacteria is linear, and there is significant difference among three cheeses(p<0.05).6. During ripening, free calcium to total calcium raised at first, then became stable later. free phosphorus to total phosphorus declined at first, then became stable later.7. Hardness and shearing force negatively correlated to scc ((p<0.01)during ripening, R is 0.5482 and 1.3977. Organoleptic evaluation shows there is sour flavor in the HSCC cheeses and it’s texture is softer and viscid.The present investigation has shown the they quality and yield of LSCC cheddar cheese was better than cheese made from HSCC milk.更多还原