Quality characteristics of non‐gluten biscuit developed from optimized cream and orange‐fleshed sweetpotato flour

Abstract

AbstractOrange‐fleshed sweetpotato (OFSP; Ipomoea batatas L.) is a new variety of sweetpotato widely accepted as a staple food in African countries due to its nutritional and health benefits. The aim of this study was to determine the quality characteristics of value added biscuit developed from optimized non‐gluten blends. King J orange‐fleshed sweetpotato (UMUSPO1), Mother's Delight orange‐fleshed sweetpotato (UMUSPO2) and cream‐fleshed sweetpotato were used. Sweetpotato storage roots were processed into flour and were incorporated with soy concentrate, date palm and sweetpotato starch. The blends were optimized using an experimental design of response surface methodology; the optimized blends were used to produce biscuits, and the biscuits were evaluated for total phenol, total flavonoid, ferric reducing antioxidant power (FRAP) and effective concentration (EC50), which is a concentration of the sample required to obtain a 50% antioxidant effect. The physical qualities and consumer acceptability of the developed and control biscuits were also assessed. The results obtained showed that the total phenolic values ranged from 2.32 to 12.54 mg GAE/g, total flavonoid values ranged from 1.11 to 12.20 mg QE/g, and FRAP values ranged from 4.38 to 22.54 mg AEE/g; EC50 of some antioxidant properties was observed to be less than (<) 2; the weight of the biscuit ranged between 4.50 and 5.59 g, diameter of the biscuit ranged between 5.30 and 6.70 cm, and the spread ratio ranged from 8.83 to 12.89. The sensory properties of the biscuit varied significantly (p < 0.05) with one another in terms of the aroma, appearance, crunchiness, taste and overall acceptability. This research showed that the optimized OFSP flour (OFSPK2) produced a good quality biscuit with the highest total phenolic, total flavonoid, and FRAP, and it exhibited good physical qualities. OFSPK2 biscuit had the highest score for its overall acceptability and compared favourably with the 100% wheat flour biscuit (control sample).