Reversibility of the temperature-dependent opacity of nonfat Mozzarella cheese

R. I. Dave
D. J. McMahon
Jeffery R. Broadbent, Utah State University
C. J. Oberg

Abstract

Salted and unsalted nonfat mozzarella cheese was made by direct acidification and stored at 4°C over 60 d. Changes in cheese opacity were measured by using reflectance L* values while the cheese was heated from 10 to 90°C, then cooled to 10°C, and reheated to 90°C. A characteristic opacity transition temperature (TOP) was obtained for each cheese. Both salt content and storage time influenced TOP. Opacity during heating, cooling, and reheating formed a hysteresis. At d 1, the unsalted cheese became opaque when heated to 20°C, but the salted cheese required heating to 40°C. As the salted cheese was aged, its TOP increased so that by 60 d the cheese did not become opaque until it was heated to 70°C.