Discipline: cheese; Keywords: Shredding efficiency, TPA, salting technique, pre-acidification.
The consumption of Mozzarella cheese in the form of Pizza toppings, salads, cheese blends have increased in recent years. The functional properties of the cheese are the ability to shred easily, melt rapidly, and reflect acceptable stretching, oiling-off and browning upon baking. Sodium chloride salt, starter cultures and acids are key ingredients in the manufacture of Mozzarella cheese and affect its functionality. Salting occurs either by brining or with dry salting. Salt acts as a regulator in the production of free amino acids and volatile fatty acids and affects water distribution and the extent of proteolysis in cheese.
Research showed that brine salting was better for some cheeses than dry salting. The salt distribution in cheese affects the concentration of sodium ions and thus has a great impact on the ionic balance among several cations within the cheese matrix. The exchange of calcium with sodium ions has an effect on the emulsification of fat. Another observation is that at lower acidification pH the calcium losses are higher and, in addition, the amount of calcium retained is affected by the type of acid used in acidification. Pre-acidification of cheese milk is beneficial for removal of calcium, thereby assisting achieving a softer curd, which melts and stretches easily.
Shreddability is defined as a cheese’s ability to cut cleanly into long thin uniform strips, have low susceptibility to form curd fines, and resist sticking, matting or clumping when loosely packed. It is apparently influenced by cheese composition and rheological properties, but these chemical and functional properties have not been studied directly before in Mozzarella type curd. Therefore, in the study by Drs Emam and Nasser, the effect of salting method together with type of pre-acidification acid on shreddability, texture profile and microstructure of Mozzarella cheese were investigated. They published their paper in Advances in Dairy Research, Volume 7, Issue 3, no 230 of 2019, the title being: Effect of Salting Technique on Shreddability, Texture Profile and Microstructure of the Pre-Acidified Cow’s Mozzarella Cheese.
Mozzarella cheeses were made conventionally from standardized full fat cow’s milk and pre-acidified with either citric, lactic or acetic acid drop-wise to pH of 6.3, using 2.5% activated yoghurt starter culture and rennet (1.5 g per 100 kg). The milled curds were salted either by the brining technique or by dry salting.
The results indicated that the brine salted cheeses were associated with significant increments in dry matter, protein, fat, calcium, cohesiveness, springiness and adhesiveness. Dry salting led to increases in ash, lactose, salt, sodium, hardness, cohesiveness, gumminess and shredding efficiency. The microstructure of the brine salted cheeses was more porous, whereas the dry salted cheeses appeared more homogeneous with a continuous protein matrix as well as less pockets. The lactic pre-acidified cheeses were the most shreddable cheeses and distinguished by the highest dry matter, protein, ash, sodium, pH, hardness and cohesiveness, as well as the densest protein network with narrow fat voids. The application of acetic acid was associated with significant increments in fat, lactose, springiness and adhesiveness, whereas the citric pre-acidified cheese showed a combination of many larger channels and smaller pores providing an increased porous structure with more sharpened protein fibres.
The study showed that Mozzarella cheese made by pre-acidification with lactic or citric acid and dry salted were hard and gummy enough to be shredded easily with low losses during shredding and are therefore preferred.