Effect of milk pasteurization temperature and in situ whey protein denaturation on the composition, texture and heat-induced functionality of half-fat Cheddar cheese

In recent years, many dairy product manufacturers pasteurize milk at temperatures higher than 72°C, so as to reduce further the risk of survival of Mycobacterium avium ssp. paratuberculosis. However, little information is available on the effect of these temperatures on cheese quality. Half-fat Cheddar cheeses (∼15%, w/w, fat) were manufactured from milk pasteurized at 72°C, 77°C, 82°C or 87°C for 26s, and analyzed over a 360d ripening period. The mean levels of whey protein denaturation in the pasteurized milks were 2.8%, 8.4%, 20.2% and 34.1% of total whey protein, respectively. Increasing pasteurization temperature significantly increased the levels of moisture and non-expressible serum and decreased the levels of protein, fat, calcium and free oil. Pasteurization temperature did not significantly affect the levels of pH 4.6-soluble N but influenced the degradation profiles of α_s1- and β-caseins. Increased pasteurization temperature significantly reduced fracture stress, fracture strain and firmness of cheeses. Raising the pasteurization temperature from 72°C to either 82°C or 87°C significantly reduced the flowability and stretchability of the heated cheese and increased its apparent viscosity; in contrast, increasing pasteurization from 72°C to 77°C did not affect these properties.