The Applied Technology Of Different Starter Cultures In Goat Cheese

Goat cheese is fermented dairy product, which was made of pasteurised goat's milk, starter cultures and rennet. Starter cultures played an important role in the cheese processing and ripening process., and also played vital role in the texture and flavor of the cheese.In this study, Guanzhong goat milk as the raw material, three kinds of starter cultures, mesophilic starter culture (Lactococcus lactis subsp.cremoris and Lactococcus lactis subsp.lactis), thermophilic starter culture(lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilus) and mixed thermophilic starter culture had been used in the production of goat cheese. The physico-chemical, biochemical and sensory characteristics of goat cheese made with different starter cultures during ripening were studied.In the first part, the acid production rate of starter cultures, starter cultures addition, acidulated conditions, coagulation properties and the yield and recovery of milk composition on the goat cheese were evaluated. The results show that acid production of three kinds of starter cultures was faster. When mesophilic starter cultures was 2%, thermophilic starter culture and mixed starter culture was 2%～3%, the goat cheese had the best cure condition.In acidification pH6.2～6.0, mesophilic and thermophilic starter culture, in the acidification pH6.4～6.2, the mixed starter culture, the goat cheese had the best cure condition.Three kinds of starter cultures on goat cheese production rate had no significant effect, while the recovery of milk composition on the goat cheese had significant difference. The the yield and recovery of milk composition of thermophilic starter culture were lower, the the yield and recovery of milk composition of mesophilic and mixed starter cultures were higher.In the second part, the physico-chemical, biochemical and sensory characteristics of goat cheese during ripening were evaluated.The results showed that during the maturity pH of thermophilic starter culture was lowest, pH of mesophilic starter culture was highest; the salt content and water content of three kinds of starter culture was no significant difference; the total protein of mesophilic starter culture was highest, the total protein of thermophilic starter culture was lowest, and the thermophilic starter culture and mixed starter culture were not significan differencet; The total fat content of mixed starter culture was highest, thermophilic starter culture and mesophilic starter culture were not significant different; the starter cultures affected the degree of protein degradation, thermophilic starter culture was liable to degrade protein and mesophilic starter culture was difficult to degrade protein; by UREA-PAGE, thermophilic starter culture was liable to degrade as-CN, mesophilic starter culture was difficult to degrade as-CN. Mixture starter culture was more easily to degradeβ-CN, produced the highest relative content ofγ-CN. Mesophilic starter culture was difficult to degradateβ-CN, produced the lowest relative content ofγ-CN; the starter cultures affected the degree of lipolysis and oxidation, thermophilic starter culture produced a higher degree of lipolysis and oxidation, and mesophilic starter culture produced a lowest degree of lipolysis and oxidation; Mixed starter cultures had best flavor in 60d, thermophilic starter cultureand mesophilic starter cultures had best flavor in 30d, the mixed starter was suitable for the application in goat milk cheese manufacture.