effect of fat reduction and using of whey protein concentrate as fat replacer on rheological properties of mozzarella cheese

background and objective : mozzarella is a soft cheese belonging to the pasta filata family, containing 18-24 % fat. the objective of this study was to determine the effect lowering mozarella fat content to 6% and adding whey protein concentrate on the rheological properties of the low-fat cheese. materials and methods : low-fat mozzarella was produced using 3 fat replacers ( dairy-lo, 35% protein simpless, 53% protein 907lsi, 90% protein ), in two forms–homogenated and nonhomogenated–with a fat content 6% and 18 % (full-fat). the low-fat cheese was produced, using the mcmahon method, fist at an experimental scale and then at a larger scale (100 kg milk) rheological properties of the samples were determined 1, 7 , 14, and 28 days after storage at 4°c. results : the rheological properties of the low-fat mozarella improved upon addition of the fat replacers. by the 28th day of storage, meltability and free-flowing oil increased . stretchability increased up to the 14th day and decreased afterwards, while hardness decreased up to the 28th day. in the homogenated samples, meltability was more, and free-flowing oil , hardness, and stretchability were less, than in the nonhomogenated samples. replacing fat with whey protein concentrate results in an increase in the misture content, which would improve the rheologoical properties (in some cases, the product was even superior to full-fat cheese). conclusion: it is recommended that low-fat mozarella be produced in iran and used in preference to full-fat mozarella. we propose that microscopic tests, too, be made on the cheese in order to make a better judgment .