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Quality of snack foods is an important consideration to consumers and industry. Primary food quality considerations of concern to consumers in particular include, chemical composition and nutritional value, as well as sensory properties. Varietal differences among sweetpotato roots and frying method have been reported to determine optimum frying temperature and time, as well as quality of sweetpotato (SP) snacks. Central composite design of response surface methodology was used to generate experimental runs to study the effect of frying temperature (140-160 °C) and time (3-6 min) combinations on quality attributes of sweetpotato crisps from yellowfleshed SP variety. The response variables were chemical composition, colour and sensory attributes of the crisps. The optimum frying conditions were generated from the data using the numerical optimization tool of the experimental design software. Sensory attributes and consumer acceptability of the optimized crisps were evaluated. Frying temperature and time combinations had varying effects on each of the quality attributes of the crisps, with only oil content being significantly affected at p<0.5. The optimum frying temperature and time was 160 °C/6.0 min and at these conditions, the quality attributes of the crisps were moisture content 2.86%, oil content 23.10%, total carotenoids content 2066.01 µg/100 g, yellowness (b*) 29.54 and crispiness (7.42).

Keywords:Yellow-fleshed sweetpotato, frying, optimization, snack, food quality