Blackwell Publishing Journal Backfiles 1879-2005
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Process Engineering, Biotechnology, Nutrition Technology
The mechanisms of water loss and their relation to muscle shortening were investigated by dry cooking in a controlled environment oven. Air was pumped vertically upward in the oven at a rate of 13.7 m3/hr. Cylindrical muscle samples were cooked at 121°C, 149°C and 177°C. The axes of these samples were in vertical, 45° and horizontal directions with respect to the oven. The muscle fibers were parallel to the axes of these samples. It is observed that total weight loss is almost independent of sample orientation, implying that the draining of fluid by gravity (a mechanism which is believed to be closely related to sample orientation) is not an important mechanism of mass transfer. The main mechanism is possibly fiber shrinkage which squeezes fluid out during cooking. Linear relationships between remaining water content and sample length were observed both before and after protein denaturation. The slopes of these two linear relations are different, suggesting that the way fluid is squeezed out is different before and after protein denaturation. Also, these slopes are almost independent of oven temperature in the 121-177°C range, suggesting that the remaining moisture content depends primarily on the shortening during cooking of a sample and only weakly on the oven temperature and initial condition (i.e., frozen or frozen-thawed) of the sample.
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