Effect of various pretreatments on the quality of vacuum-fried carrot chips

Carrot slices were subjected to the following four different pretreatments prior to vacuum frying: (1) blanching, (2) blanching and air drying, (3) blanching and osmotic dehydration, (4) blanching, osmotic dehydration, followed by freezing. The effects of these pretreatments on the physicochemical properties and fat distribution in vacuum-fried carrot chips were also investigated. There were significant differences in the total yield, amounts of carotenes, vitamin C, and the color values of carrot chips following different pretreatments (P < 0.05). Pretreatment significantly affected the water content, fat content, and water activity of carrot chips (P < 0.05), while there were no significant differences in the breaking force of carrot chips treated with different pretreatments (P > 0.05). Spearman correlation analysis showed a high positive correlation between the fat content of carrot chips and the initial water content of carrot slices. The fat distribution pattern depended on the initial water content and the structure of the material left by water evaporation.