Investigation On Processing Technology And Uniform Ripening Of Camembert Cheese

Camembert cheese is a kind of mold-ripened soft cheese. In this thesis, the processing technology, ripening characteristics and uniform ripening were studied in order to provide basic theory for Camembert cheese processing and storage. And it also aimed at controlling ripening degree, prolonging the shelf-life and maintaining cheese security.The key factors affecting Camembert cheese processing were studied through orthogonal experimental design. The optimized parameters included: starter dose 0.01%; CaCl₂ in cheese milk 0.02%; cutting size of curd 15×15×15mm; molding pH 5.4; salt content 1.5%; mould addition of 0.005%.The physicochemical characteristics of Camembert cheese during ripening period showed that the moisture decreased during the primary ripening, and then it appeared no significant changes and maintained approximate 50%. Both the pH value of surface and inner decreased at the beginning and then increased, finally the pH value of surface was 7.0 and inner was 6.0. Due to lactobacillus and mold enzymes contributed to the proteolysis, the pH4. 6 acetate buffer soluble nitrogen, 12% TCA soluble nitrogen and FAA increased during cheese ripening. The content of total FFAs increased during ripening, and the main FFAs were even carbon medium-chain FFAs (C12-C18). Each index of TPA decreased during ripening.Headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the volatiles in Camembert cheese of which the ripening period was 15, 30 and 45 d, respectively. The main volatiles were alcohols, aldehydes, ketones, esters, benzenes, alkenes and volatile organic acids. During the ripening, most of alcohols were disappeared; aldehydes increased, and most of them participated in the conversion between acids and esters; ketones increased considerably, and most of them were methyl ketones; acids decreased or disappeared; esters increased considerably.As over-ripening and uneven ripening between surface and interior occurred, several methods were tried for uniform ripening. The results showed adding Lactobacillus helveticus (dose of 0.005%, w/w), vacuum package and low temperature storage (2～6℃) had positive effects on the uniform ripening of Camembert cheese.