Effect of pH and calcium level on the biochemical, textural and functional properties of reduced-fat Mozzarella cheese

Reduced-fat Mozzarella cheeses were made using starter culture (control, CL), lactic acid (directly acidified, DA) or a combination of starter culture and lactic acid (DAS1 and DAS2) to reduce the pH during manufacture. The resultant cheeses differed in pH at 5 d and calcium content (mg g−1 protein): CL, 5.42 and 28.58; DA, 5.89 and 19.38; DAS1, 5.64 and 18.54; and DAS2, 5.49 and 18.31. Compared to CL, the DA and DAS cheeses had higher levels of moisture, moisture-in-non-fat substances, non-expressible serum (g g−1protein), and lower levels of protein. These changes were paralleled by higher mean values for stretchability and flowability, and lower mean values for firmness in the DA and DAS cheeses over the 70-d ripening period. Reducing the pH from 5.89 in the DA cheese to ⩽5.64 in the DAS cheeses, by adding starter culture and increasing the time between whey drainage and curd milling, increased primary proteolysis in the unheated cheese and the stretchability and flowability (as measured using the modified Schreiber method) of the melted cheese.