Influence of collapsed structure on stability of ?-carotene in freeze-dried mangoes.
Harnkarnsujarit N., Charoenrein S.
Author Affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand.
Food Research International 44 : 3188-3194
Abstract : This study aimed to investigate the effect of structural collapse of freeze-dried mangoes on stability of ?-carotene. Three different freeze-drying protocols were performed to produce collapse and non-collapse structures of freeze-dried mangoes. Thermal transitions of samples were determined using a differential scanning calorimeter. ?-carotene content was monitored during storage using high-performance liquid chromatography. The ?-carotene degradation followed first-order kinetics. Mangoes freeze-dried at above ice melting temperature revealed structural collapse which decreased ?-carotene degradation rate. These dense and collapsed structures formed prevented oxygen penetration through the solids. Liquid nitrogen freezing also gave structural collapse coincided with surface cracking on freeze-dried mangoes. Such structure showed no protective effect on ?-carotene as similar degradation rate to non-collapsed systems was observed. The cracking on mango surface potentially allows high oxygen penetration through the solids thus promoting ?-carotene loss. These findings give benefit to the production of freeze-dried fruits to increase storage stability of ?-carotene.