Functional properties of Mozzarella cheese for its end use application

Cheese is an extremely versatile food product that has a wide range of flavor, textures and end uses. The vast majority of cheese is eaten not by itself, but as part of another food. As an ingredient in foods, cheese is required to exhibit functional characteristics in the raw as well as cooked forms. Melting, stretching, free-oil formation, elasticity and browning are the functional properties considered to be significant for Mozzarella cheese. When a cheese is destined for its end use, some of its unique characteristics play a significant role in the products acceptability. For instance pH of cheese determines the cheese structure which in turn decides the cheese shredability and meltability properties. The residual galactose content in cheese mass determines the propensity of cheese to brown during baking. Development of 'tailor-made cheese' involves focusing on manipulation of such unique traits of cheese in order to obtain the desired characteristics for its end use application suiting the varied consumer's whims and wishes. This comprehensive review paper will provide an insight to the cheese maker regarding the factors determining the functional properties of cheese and also for the pizza manufacturers to decide which age of cheese to be used which will perform well in baking applications.

Effect of camel chymosin on the texture, functionality, and sensory properties of low-moisture, part-skim Mozzarella cheese

The objective of this study was to compare the effect of coagulant (bovine calf chymosin, BCC, or camel chymosin, CC), on the functional and sensory properties and performance shelf-life of low-moisture, part-skim (LMPS) Mozzarella. Both chymosins were used at 2 levels [0.05 and 0.037 international milk clotting units (IMCU)/mL], and clotting temperature was varied to achieve similar gelation times for each treatment (as this also affects cheese properties). Functionality was assessed at various cheese ages using dynamic low-amplitude oscillatory rheology and performance of baked cheese on pizza. Cheese composition was not significantly different between treatments. The level of total calcium or insoluble (INSOL) calcium did not differ significantly among the cheeses initially or during ripening. Proteolysis in cheese made with BCC was higher than in cheeses made with CC. At 84 d of ripening, maximum loss tangent values were not significantly different in the cheeses, suggesting that these cheeses had similar melt characteristics. After 14 d of cheese ripening, the crossover temperature (loss tangent = 1 or melting temperature) was higher when CC was used as coagulant. This was due to lower proteolysis in the CC cheeses compared with those made with BCC because the pH and INSOL calcium levels were similar in all cheeses. Cheeses made with CC maintained higher hardness values over 84 d of ripening compared with BCC and maintained higher sensory firmness values and adhesiveness of mass scores during ripening. When melted on pizzas, cheese made with CC had lower blister quantity and the cheeses were firmer and chewier. Because the 2 types of cheeses had similar moisture contents, pH values, and INSOL Ca levels, differences in proteolysis were responsible for the firmer and chewier texture of CC cheeses. When cheese performance on baked pizza was analyzed, properties such as blister quantity, strand thickness, hardness, and chewiness were maintained for a longer ripening time than cheeses made with BCC, indicating that use of CC could help to extend the performance shelf-life of LMPS Mozzarella.

Effect of frozen storage on physical properties of pasta filata and nonpasta filata Mozzarella cheeses

The effects of 1) ripening 2, 7, and 14 d at 7 degrees C before freezing; 2) tempering 7, and 14 d at 7 degrees C after freezing; and 3) frozen storage for 1 and 4 wk at -20 degrees C, on the meltability, stretchability, and microstructure of pasta filata and nonpasta filata Mozzarella cheeses were investigated. Cheeses were cut into 5 x 10 x 7-cm blocks and vacuum-sealed 1 d after manufacture. The results were compared to the corresponding results obtained with unfrozen control samples, aged at 7 degrees C between 2 and 21 d. The changes in physical properties of frozen-stored pasta filata and nonpasta filata Mozzarella cheeses were consistent with critical damage to the cheese microstructure as compared to the unfrozen control samples. Generally, aging before and tempering after freezing resulted in increased meltability of both frozen-stored pasta filata and nonpasta filata Mozzarella cheeses. The stretchability of frozen-stored pasta filata Mozzarella cheese increased during tempering, but that of nonpasta filata Mozzarella cheese decreased during aging and tempering. In most cases, one-week frozen stored pasta filata Mozzarella cheese had higher meltability and stretchability than 4-wk frozen-stored sample. For 1-wk frozen-stored nonpasta filata Mozzarella cheese, the meltability increased but stretchability decreased when it was frozen-stored for 4 wk.

Test for measuring the stretchability of melted cheese

A test for measuring the stretchability of cheese was developed by adapting a texture-profile analyzer to pull strands of cheese upwards from a reservoir of melted cheese. Seven different cheeses were analyzed using the Utah State University stretch test. The cheeses were also analyzed for apparent viscosity with a helical viscometer, for meltability using a tube melt test, and for stretch using the pizza-fork test. Cheese was placed into a stainless steel cup and tempered in a water bath at 60, 70, 80, or 90 degrees C for 30 min before analysis. The cup was then placed in a water-jacketed holder mounted on the base of the instrument. A three-pronged hook-shaped probe was lowered into the melted cheese and then pulled vertically until all cheese strands broke or 30 cm was reached. This produced a stretch profile as the probe was lifted through the reservoir of melted cheese and then pulled strands of cheese upwards. Three parameters were defined to characterize the stretchability of the cheese. The maximum load, obtained as the probe was lifted through the cheese, was defined as melt strength (F(M)). The distance to which cheese strands were lifted was defined as stretch length (SL). The load exerted on the probe as the strands of cheese were being stretched was defined as stretch quality (SQ). There was a correlation between F(M) and apparent viscosity. There was also some correlation between SL measured by the fork test and SL when the cheese was tested at 90 degrees C, but no correlation occurred at lower temperatures.

Nuclear magnetic resonance study of water mobility in pasta filata and non-pasta filata mozzarella

Changes in molecular mobility of water in pasta filata and non-pasta filata Mozzarella cheeses were investigated during the first 10 d of storage using nuclear magnetic resonance (NMR) relaxation techniques. Water in pasta filata Mozzarella was classified into two fractions by spin-spin relaxation times, T21 and T22, and corresponding proton intensities, A1 and A2, representing low and high molecular mobility, respectively. Increase in A1 (and decrease in A2) suggested that, there was a redistribution of water from more- to less-mobile fraction (from T22 to T21 fraction) during the first 10 d of storage. The NMR data did not indicate the two-state behavior of water molecules in non-pasta filata Mozzarella. However, the T2 values of non-pasta filata Mozzarella were comparable to the T21 values of pasta filata Mozzarella indicating that the molecular mobility of water in non-pasta filata Mozzarella is comparable to that of the less mobile water fraction in pasta filata Mozzarella. Generally, T2 and T1 values of pasta filata and non-pasta filata Mozzarella cheeses increased during the 10-d storage. This is believed to be due to structural changes in the protein matrix.

Effect of manufacturing factors, composition, and proteolysis on the functional characteristics of mozzarella cheese

Shredding and melting characteristics are vital to the function of low-moisture Mozzarella cheeses that are used as ingredients for pizza and related foods. Newly manufactured Mozzarella melts to a tough, extremely elastic, and somewhat granular consistency with limited stretch that is unacceptable for pizza. However, during the first few weeks of refrigerated storage, a dramatic transformation occurs as the unmelted cheese becomes softer and the melted cheese becomes more viscous, less elastic, and highly stretchable. Thus, the cheese attains optimal functionality for pizza. Over longer periods, Mozzarella becomes excessively soft and fluid when melted and is no longer acceptable for pizza. Low-moisture Mozzarella is correctly viewed as a cheese that requires aging. The functional characteristics of low-moisture Mozzarella are due initially to the chemical composition, including fat, moisture, NaCl, and mineral contents, and the structure of the paracasein curd matrix that is established during manufacture. Changes in functional characteristics during aging are directly related to proteolysis rate and possibly proteolytic specificity. Proteolysis during aging is influenced by manufacturing factors such as starter culture, coagulant, and stretching temperature, and possibly to indigenous proteases in the cheesemilk such as plasmin.