[Effects of soy-protein isolate coating on the properties of French fries using response surface methodology]

ABSTRACT

The use of edible coatings is a suitable method to reduce oil uptake in fried foods. In this research, the effects of soy-protein isolate [SPI] coating plasticized with sorbitol on oil uptake reduction and sensory and physical properties of deep-fat fried French fries were investigated. Potato strips were coated with SPI plasticized with sorbitol at different concentrations. The effect of coating on oilp uptake reduction, water retention, crispiness and color change of French fries were determined, using response surface methodology. Moreover, the sensory acceptability of the tried potato samples was assessed. The results showed that the protein and sorbitol concentrations are the major factors affecting water retention, oil uptake reduction, crispiness, and color of the fried potato samples. Coating resulted in oil uptake reduction and water retention up to 40% +/- 2 and 80%, respectively. Nonsignificant differences in sensory characteristics of coated and uncoated samples were observed. The results showed that the models based on the response surface methodology are quite suitable for the evaluation of the effects of coating on the properties of french fries. The application of soy-protein coating reduces oil uptake, while it does not affect the sensory characteristics, of fried potato strips. It is concluded, then, that SPI coating can improve the organoleptic and nutritional properties of fried food products