KINETICS OF QUALITY CHANGES OF GREEN PEAS AND WHITE BEANS DURING THERMAL-PROCESSING

The design of optimal thermal processes relies on relevant and accurat e kinetic data for bacterial inactivation and quality evolution. By us e of taste panels, kinetic data for quality evolution of peas (Pisum s ativum L., var. Wavette) and white beans (Phaseolus vulgaris, subsp. n anus Metz., var. Manteca de leon) were obtained. The thermal destructi on kinetics of these quality attributes was described using two altern ative models, the thermal death time model (z- and D-value) and the Ar rhenius model (E(a)-and k-value). Kinetic parameters were estimated by use of three least squares methods: two-step linear regression, multi ple linear regression and nonlinear regression. Multilinear regression analysis was selected for parameter estimation. The following tempera ture coefficients were obtained: colour of peas (z = 26.4-degrees-C; E (a) = 102.4 kJ/mole), hardness of peas (z = 28.5-degrees-C, E(a) = 94. 9 kJ/mole) hardness of beans (z = 21.3-degrees-C, E(a) = 130.8 kJ/mole ) and appearance of beans (z = 24.3-degrees-C, E(a) = 118.7 kJ/mole).