COLLECTION of ACCURATE EXPERIMENTAL DATA FOR TESTING the PERFORMANCE of SIMPLE METHODS FOR FOOD FREEZING TIME PREDICTION

Abstract

Objective testing of the accuracy of food freezing time prediction formulae requires experimental data to be of high quality. It is shown that there are shortcomings in commonly used experimental methods, particularly relating to minimizing heat transfer in all but the required dimensions in experiments with the slab and infinite cylinder shapes, in maintaining uniformity of surface heat transfer coefficients across a sample, and in measurement of surface heat transfer coefficients. Broad guidelines to ensure that the errors introduced by experimental techniques are negligibly s m l l are proposed. Major published experimental data sets are compared to these guidelines and comments made on their likely accuracy.

Computational Simulation and Developments Applied to Food Thermal Processing

“…The common practice to construct a mathematical diffusion model has been based on the solution of the energy and mass equations with a third-kind boundary condition on the surface. Spatial and time variations of the local convective heat transfer coefficients caused errors in the range of 5-15% compared to analytical models and with respect to the experimental data [50][51][52]. In industrial practice a simplified fast predictive method is preferred and the development of simple and available software is desired [53].…”

Application and testing of a simple method for predicting chilling times for hoki (Macruronus novaezelandiae)

“…Future studies should examine the exact location of the thermal centre in hoki, either experimentally or by finite element analysis. Cleland, Cleland, and Jones (1994) presented an in-depth discussion of factors influencing the accuracy of experimental data for food cooling and freezing processes, including guidelines on the placement of temperature measurement probes. Measurements of centre temperature should preferably be made using multiple thermocouple probes, thus allowing the slowest-cooling measured temperature to be chosen as most closely representing the thermal centre.…”

Experimental Measures of the Effective Heat Transfer Coefficients in Air Blast Freezers for the Processing of Fruit Pulps

“…A great range of magnitudes for superficial heat transfer coefficients (" h ") were related. Nicolaï and De Baedemaeker (1996), cited typical values of 300 W/m 2o C obtained during the hydrocooling of fruits and vegetables while in the cooling with forced air, " h " can vary between 8 and 68 W/m 2o C. Information involving values of " h " for the food surfaces with regular shapes meet available in literature (Arce and Sweat, 1980;Lind, 1988;Cleland, 1990;LeBlanc et al, 1990 a,b;Kondjoyan and Daudin, 1993;Cleland et all., 1994;Salvadori et al, 1996).…”