Relaxation Studies of Acid Type Cheese Texture by a Constant Speed Cone Penetrometric Method

A constant speed cone penetrometer (Stevens, UK) connected to a microcomputer (Amstrad CPC 6128, UK) was used to analyse the tangential stress during penetration and the stress relaxation after the penetration had stopped. For acid cheese samples containing between 12 and 39% of total solids the tangential stress was between 0.3 and 14 kPa. Stress relaxation was best reproduced (coefficient of variation CV = 0.6%) by the Avrami (1939, 1940, 1941) and Nutting (1921) equations (CV = 1.4%). Using the models of Peleg (1979) and Maxwell (1868) the fit was much worse (CV = 4.9% and 9.5% respectively). Nonrelaxing stress represented 10 to 30% of the initial stress level.