Influence of coagulating enzymes iron fortification and packaging methods on the quality characteristics and shelf life of mozzarella cheese

Abstract

newlineA study was carried out to develop iron fortified mozzarella cheese from cow s milk, goat s newlinemilk and mixed milk using kiwifruit crude extract. The experiment was conducted in the laboratories newlineof Department of Livestock Products Technology, All India Coordinated Research Project on Post- newlineHarvest Engineering and Technology and Department of Veterinary Microbiology, College of newlineVeterinary Science, Assam Agricultural University, Khanapara, Guwahati -781 022. newlineKiwifruit crude extract was prepared from fresh kiwi fruits (Actinidia chinensis). The newlineproteolytic enzyme present in the crude extract identified through SDS-PAGE was actinidin having newlinean apparent molecular mass of 24.5 kDa. Optimum level of kiwifruit extract can be used at newline150and#956;g/ml of milk for complete coagulation within 27min for preparation of iron fortified mozzarella newlinecheese. newlineMozzarella cheese can be efficiently fortified with ferric chloride safely without newlinegiving rise to off-flavour in the product at an optimum level of 1g/lts of milk. Maximum newlineretention of iron (51.29mg/kg) was recorded in mixed milk iron fortified mozzarella cheese newlinesamples. newlineEffect of enzymes and different types of milk were studied on the physico-chemical newlineproperties (pH, acidity), proximate composition, water activity, meltability, colour profile, texture newlineanalysis, yield, organoleptic properties and microbiological quality of iron fortified mozzarella newlinecheese. newlineProximate composition revealed highest values for total solid and ash content for newlinegoat s milk iron and fat in mixed milk iron fortified mozzarella cheese, while lowest newlinemoisture and fat content were recorded in goat s milk iron fortified mozzarella cheese in the newlinetreatment group. newlineTexture profile analysis of goat s milk iron fortified mozzarella cheese samples newlineshowed higher values for hardness, springiness, cohesiveness and chewiness while cow s newlinemilk iron fortified mozzarella cheese samples recorded higher value for adhesiveness and newlinemixed milk iron fortified mozzarella cheese for gumminess parameters. newlineThere was a gradual increase in curd syneresis with advancement of time. Curd newlinesyneresis was noted to be highest in cow s milk followed by goat milk and least was newlineobserved in mixed milk over a period of 120min. newlineMixed milk iron fortified mozzarella cheese enjoyed superior ratings for all the newlinesensory attributes, viz., appearance, colour, body and texture, flavour, saltiness and overall newlineacceptability. newlineThe TVC increased gradually from 0d till 15d of refrigerated storage for all the newlinesamples of iron fortified mozzarella cheese under both aerobic and vacuum packaging newlineconditions irrespective of the types of milk and enzymes used. Under aerobic packaging newlinecondition, higher TVC were observed for goat s milk sample in both control and treatment newlinegroup all throughout the storage period. Mixed milk iron fortified mozzarella cheese newlineexhibited least count in both the groups. The TVC of all the cheese samples were higher in newlineaerobic packaging compared to vacuum packing. newlineNil counts for Yeast and moulds, E. coli, Coliform, Staph. aureus, Salmonella, newlineShigella, Listeria monocytogenes and anaerobic spore counts were noted for all the types of newlinecheese samples under both the packaging conditions, all throughout the storage period, newlineunder refrigerated condition newlineBest before use of mixed milk iron fortified mozzarella cheese samples was found to newlinebe 15d under both the packaging conditions with lesser TVC in the vacuum packaged newlinesamples. newlineBased on proximate composition, meltability, sensory attributes microbiological newlinequality and cost of production, the technology developed under treatment group for mixed newlinemilk mozzarella cheese is recommended and a suitable protocol for commercial production newlineof iron fortified mozzarella cheese has been proposed.