INFLUENCE OF COAGULATING ENZYMES, IRON FORTIFICATION AND PACKAGING METHODS ON THE QUALITY CHARACTERISTICS AND SHELF-LIFE OF MOZZARELLA CHEESE
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Date
2019-01
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College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati
Abstract
A study was carried out to develop iron fortified mozzarella cheese from cow’s milk, goat’s
milk and mixed milk using kiwifruit crude extract. The experiment was conducted in the laboratories
of Department of Livestock Products Technology, All India Coordinated Research Project on Post-
Harvest Engineering and Technology and Department of Veterinary Microbiology, College of
Veterinary Science, Assam Agricultural University, Khanapara, Guwahati -781 022.
Kiwifruit crude extract was prepared from fresh kiwi fruits (Actinidia chinensis). The
proteolytic enzyme present in the crude extract identified through SDS-PAGE was actinidin having
an apparent molecular mass of 24.5 kDa. Optimum level of kiwifruit extract can be used @
150μg/ml of milk for complete coagulation within 27min for preparation of iron fortified mozzarella
cheese.
Mozzarella cheese can be efficiently fortified with ferric chloride safely without
giving rise to off-flavour in the product at an optimum level of 1g/lts of milk. Maximum
retention of iron (51.29mg/kg) was recorded in mixed milk iron fortified mozzarella cheese
samples.
Effect of enzymes and different types of milk were studied on the physico-chemical
properties (pH, acidity), proximate composition, water activity, meltability, colour profile, texture
analysis, yield, organoleptic properties and microbiological quality of iron fortified mozzarella
cheese.
Proximate composition revealed highest values for total solid and ash content for
goat’s milk iron and fat in mixed milk iron fortified mozzarella cheese, while lowest
moisture and fat content were recorded in goat’s milk iron fortified mozzarella cheese in the
treatment group.
Texture profile analysis of goat’s milk iron fortified mozzarella cheese samples
showed higher values for hardness, springiness, cohesiveness and chewiness while cow’s
milk iron fortified mozzarella cheese samples recorded higher value for adhesiveness and
mixed milk iron fortified mozzarella cheese for gumminess parameters.
There was a gradual increase in curd syneresis with advancement of time. Curd
syneresis was noted to be highest in cow’s milk followed by goat milk and least was
observed in mixed milk over a period of 120min.
Mixed milk iron fortified mozzarella cheese enjoyed superior ratings for all the
sensory attributes, viz., appearance, colour, body and texture, flavour, saltiness and overall
acceptability.
The TVC increased gradually from 0d till 15d of refrigerated storage for all the
samples of iron fortified mozzarella cheese under both aerobic and vacuum packaging
conditions irrespective of the types of milk and enzymes used. Under aerobic packaging
condition, higher TVC were observed for goat’s milk sample in both control and treatment
group all throughout the storage period. Mixed milk iron fortified mozzarella cheese
exhibited least count in both the groups. The TVC of all the cheese samples were higher in
aerobic packaging compared to vacuum packing.
Nil counts for Yeast and moulds, E. coli, Coliform, Staph. aureus, Salmonella,
Shigella, Listeria monocytogenes and anaerobic spore counts were noted for all the types of
cheese samples under both the packaging conditions, all throughout the storage period,
under refrigerated condition
Best before use of mixed milk iron fortified mozzarella cheese samples was found to
be 15d under both the packaging conditions with lesser TVC in the vacuum packaged
samples.
Based on proximate composition, meltability, sensory attributes microbiological
quality and cost of production, the technology developed under treatment group for mixed
milk mozzarella cheese is recommended and a suitable protocol for commercial production
of iron fortified mozzarella cheese has been proposed.