Kinetics of Color Changes During Pretreatment Blanching of Pineapple (Ananas Comosus) Fruit Variety 'MD2'

Drying is an intensive unit operation used to preserve the pineapple fruit. In this study, the kinetics of color degradation in pineapple slices during blanching as pretreatment with combined microwave and convection drying at different temperatures (110, 120, 130, and 140 degrees C) and drying times (5, 10, 20, 25, and 30 min) were determined. L*, b*, chroma, and total color difference (TCD) increased as the drying temperature and time increased. As for the a* parameter, it is not dependent on the drying temperature. In addition, blanching pretreatment prior to drying can affect and change the color of pineapple slices by increasing L*, a*, chroma, and TCD compared to no blanching. Nevertheless, it maintains the yellowness (b*) in pineapple slices. As for kinetic models, zero-order best described the changes of L*, a*, b*, chroma, and TCD, while first-order best pronounced the parameters L*, b*, chroma, and TCD. These findings would be useful in designing thermal processes and related calculations for the pineapple fruit.