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Journal of Food Engineering, Vol.28, No.1, 85-107, 1996
Modelling of temperature and weight loss kinetics during meat chilling for time-variable conditions using an analytical-based method .2. Calculations versus measurements on wet plaster cylinders and cast
Calculations carried out using the hear-transfer model in an infinite cylinder; adapted to account for time-variable boundary conditions (see part I of this series of papers), are compared to experimental temperature and weight loss kinetics. The model is first validated by comparing the calculations with measurements carried out on wet plaster cylinders (diameters 12.7, 10 and 7.5 cm) chilled under the following conditions: (1) under constant conditions (34 trials) covering a wide range of variations in air properties: 1 < V-a < 2.2 m/s, 0 < T-a < 10 degrees C and 44 < RH < close to saturation, and (2) under rime-variable conditions (12 trials) for an air velocity varying between 0.6 and 2.2 mis and an air temperature varying between -15 and 10 degrees C. Without adjustments, the temperature kinetics at different points within the sample are predicted under constant and time-variable conditions with an error margin of 1 degrees C. The relative error in chilling time prediction is 5%. Weight loss at the end of chilling, which is around 2% of the original weight, is calculated with an absolute error of 0.1%. The ability of the model to simulate the chilling of a plaster mould of a pork carcass hindquarter is then tested. Five trials carried out with air velocities ranging from 0.5 to 2.2 m/s yielded a shape factor adjustment. The mean temperature variation of the thickest section of the sample was then successfully simulated A discussion on the difficulties encountered in simulating the weight loss kinetics with the same precision as for cylinders, reveals the limits of the analytical approach.