Journal of food processing and preservation vol:18 issue:5 pages:407-420
The temperature dependence of the rate index of thermal softening of white beans (Phaseolus vulgaris, subsp. nanus Metz. variety Manteca de Leon) was determined within the temperature range of 90C to 122C using an industrial FMC tenderometer and a trained sensory panel. Based on sensorial results a first order reaction was assumed, whereas the tenderometer values were described by a biphasic model. Using a multiple linear regression analysis on the sensorial data, the activation energy for the heat induced firmness degradation of beans was calculated as 130.8 kJ/mole. Activation energies of both phases of the biphasic model were obtained by a two-step linear regression on the tenderometer data. Activation energies of both phases were equal, namely 105.1 kJ/mole.