Characteristics of white brined cheeses made from goat milk subjected to different heat treatments

Proizvodnja i prerada kozjeg mleka je dinamična grana mlekarske industrije koja je u usponu i igra važnu ulogu u ekonomskom razvoju mnogih zemalјa. Poslednjih godina na tržištu mlečnih proizvoda širom sveta, kozji mlečni proizvodi se nalaze u žiži interesovanja. Termički tretmani su deo postupka proizvodnje velikog broja mlečnih proizvoda, a imaju za cilј pobolјšanje pojedinih karakteristika proizvoda, podizanje nivoa njihove bezbednosti, kao i produženje roka trajanja. Proteini mleka podvrgnutog termičkom tretmanu menjaju svoje funkcionalne osobine što nalazi široku primenu u prehrambenoj i farmaceutskoj industriji. Za razliku od kravljeg mleka koje nakon visokih termičkih tretmana menja svoje tehnološke karakteristike, što otežava proces proizvodnje i dovodi do stvaranja sira lošijeg kvaliteta, za kozje mleko postoje naznake u literaturi, da se nakon termičkog tretmana koagulacija neometano odvija, što ukazuje na potencijalnu mogućnost dobijanja sira sa uvećanim randmanom i nutritivnom vrednošću. Cilj ovog rada je bio da se ispita mogućnost proizvodnje kozjih belih sireva u salamuri dobijenih od mleka tretiranog režimima termičke obrade: 80°C/5 min i 90°C/5 min, bez prilagođavanja faktora proizvodnje u odnosu na kontrolnu varijantu proizvedenu od mleka tretiranog klasičnim postupkom niske pasterizacije (65°C/30 min), kao i da se ispitaju karakteristike ovako dobijenih sireva. Navedeni cilj sproveden je kroz tri faze. Ispitivan je uticaj termičkih tretmana kozjeg mleka na (1) intenzitet promena na proteinima punomasnog i obranog kozjeg mleka, kako bi se dobila jasnija slika o sirovini koja se koristi za proizvodnju sireva; (2) enzimsku koagulaciju kroz određivanje parametara koagulacije (3) tok zrenja kozjih belih sireva u salamuri, po pitanju osnovnih fizičko-hemijskih parametara, proteolitičkih promena, kao i promena teksturalnih i senzornih svojstava...Production and processing of goat’s milk is a dynamic and growing industry that is becoming an important part of economy in many countries. In receant years, the dairy products market has been showing great interest in goat’s milk products. Heat treatment has been used in dairy processing to enhance desirable properties of the products, such as texture and taste, to ensure their safety and to prolong their shelf-life. Heat-treatment modifies functional properties of milk proteins and the procedure has been widely used in the food, cosmetics and pharmacutical industries. Heat-treatment at high temperatures causes significant changes in the technological characteristics of cow’s milk; it has a negative effect on the cheese-making process and lowers the quality of cheese. However, when goat’s milk is subjected to high-heat treatment, it appears that the coagulation process is not impeded; this offers a possibility to produce cheeses from high-heat-treated milk with increased nutritional value and with a higher production yield. The object of this study was to investigate the feasibility of production of white brined goat’s cheese from milk heated at 80°C/5min and 90°C/5min, following the same production method used for cheeses made from pasteurized milk (65°C/30min); the characteristics of those cheeses were also to be analyzed and evaluated. The experiments were conducted in three phases: (1) in order to obtain a clearer picture of the raw materials used for cheese production, changes in the protein structure of whole and of skimmed goat’s milk after high-heat treatments were analyzed; (2) the coagulation parameters of high-heat-treated milk during enzymatic coagulation were measured in order to estimate the effect of high-heat treatments on enzymatic coagulation; (3) the maturing process of white brined goat’s cheeses produced from high-heat-treated milk was analyzed as a function of basic physico-chemical parameters, of the proteolytic changes and of the changes in textural and sensory properties..