LAUSR

A general formula was derived for predicting come-up time correction factors needed to accurately estimate the values of food in containers subjected to time variable heating medium temperatures during the come-up period of heat sterilization process. It would be applicable to any food with any mode of heat transfer regardless to container geometry because it was derived from empirical formulas containing and values, which were developed for food temperature estimation. From this general formula, a new procedure was developed for calculating the come-up time correction factors by using experimental come-up heating medium temperatures. In this investigation, however, come-up time correction factors were calculated by the developed procedure using time-temperature data obtained from mathematical functions representing assumed come-up heating medium temperature history curves. By comparing the results with those calculated from theoretical formulas, which were derived by substituting these mathematical functions for the general formula, it was found that the come-up time correction factors could be accurately calculated by the developed procedure. Practical Applications The and values, which are accurately estimated from the heating curve, may be used for determining (thermal diffusivity) and (surface heat transfer coefficient/thermal conductivity) necessary to heat penetration simulation for heat conduction food in containers, which are approximated by cylinders, slabs, or spheres.