Investigation On Optimization In Processing Technology And Volatile Flavor Compounds Of Tilsit Cheese

Processing technology and changes in processing have been studied to obtain the optimized conditions for Tilsit cheese processing.Key factors affecting qualities of Tilsit cheese were studied through orthogonal experimental design. The optimized parameters included:starter dose is0.01%, CaCl2in cheese milk0.01%, molding pH5.4, scalding temperature42℃for30min, salting in18%brine for6h and Brevibacterium linens was sprayed on the surface of cheese at the concentration of0.10g/mL. After60-day’s ripening, well accepted cheeses can be obtained.The physicochemical characteristics of Tilsit cheese during ripening period showed that the moisture decreased during the primary ripening, and then it appeared no significant changes and maintained approximate50%. The pH value decreased at the beginning and then increased, finally the pH value of surface was6.20. Lactobacillus and Brevibacterium linens contributed significantly to the proteolysis.The pH4.6acetate buffer soluble nitrogen,12%TCA soluble nitrogen and FAA increased during cheese ripening. The content of total FFAs increased during ripening. Indexes of TPA all decreased during ripening.The microstructures of cheese were observed with SEM. Results indicated: cheese protein and fat hydrolysis obviously. After90-day’s ripening, protein micelles were not obviously observed, whereas, coagulated proteins almost fused together, which indicated a higher degree of hydrolysis and micellar structure has been severely damaged.Headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the volatiles in Tilsit cheese, the ripening period of which were30d,60d and90d respectively. The main volatiles were alcohols, aldehydes, ketones, esters, benzenes, alkenes and volatile organic acids. During the ripening most of volatile compounds increased, and esters increased considerably.The physicochemical characteristics and acceptability of the samples showed the process parameters are optimized. Brevibacterium linens spraying on surface significantly improves texture and flavor, accelerating Tilisit cheese ripening.