KINETICS OF SENSORY CHANGES AND SHELF-LIFE OF MINIMALLY PROCESSED STAR FRUIT

Abstract

In order to establish appropriate conditions of storage, to reduce losses of quality in the distribution of fresh-cut star fruit (Averrhoa carambola L.), minimally processed fruits were stored at 4.9, 7.8 and 12.8 ºC for 14, 8 and 3 d, respectively. The samples were evaluated by a trained panel and kinetics of sensory changes were determined by fitting models of zero and first order, obtained from a deterioration general model, based on the coefficient of determination (R²) obtained by linear regression analysis. From the kinetic constants of the fitted model, the activation energy (E_a) for each attribute was obtained by means of the Arrhenius equation. The shelf-life of the product was estimated from the kinetic constants and the middle value of the linear scale of 10 cm as shelf-life limit value, for each attribute evaluated. Changes in aroma, off-odor, brightness, flavor, cohesiveness and juiciness, fitted better to the first-order kinetics and the rest to zero-order kinetics. Greatest values (E_a) were for cohesiveness, off-odor and off-flavor (254.87, 225.60 y 214.31 kJ mol^-1, respectively), while the lowest values were for color, juiciness and fermented odor (134.18, 141.35 y 141.38 kJ mol^-1). Shelf-life estimated for the minimally processed star fruit was 11, 6 and 2 d at 4.9, 7.8 and 12.8 ºC, respectively. The values estimated of E_a highlight the necessity of a proper management of temperature, during the processing, storage and marketing of the product. The changes that limited shelf-life were browning and off-odors.