Process optimization by response surface methodology and quality attributes of vacuum fried yellow fleshed sweetpotato (Ipomoea batatas L.) chips

A three-level Box-Behnken design was employed to study the effects and optimize the process parameters for vacuum frying of yellow fleshed sweetpotato (YFSP) slices for the production of healthy and nutritious fried snacks. The critical factors selected for the investigation were frying temperature (108-136 degrees C), vacuum pressure (4.91-19.91 cmHg) and frying time (3-9 min). The experimental results were fitted with a second-order polynomial equation by a multiple regression analysis and more than 80% of the variation could be predicted by the models. The optimal conditions for vacuum flying of YFSP slices determined using the numerical analysis were vacuum pressure of 10.12 cmHg at 108 degrees C for 9 min with desirability concept of 0.609. When optimized, vacuum fried samples were compared with atmospheric fried samples; the former absorbed about 60.42% less oil, and retained higher carotenoid (6.01 mg/g), with lower breaking force (15.9 N). Panellists preferred and accepted the optimized vacuum fried samples in all the sensory attributes investigated. The results suggested that vacuum frying of yellow fleshed sweetpotato chips is a better alternative to produce fried chips of acceptable and nutritional qualities. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.