Effect of Drying Methods on Phytochemical Composition of Orange Fruit (Citrus sinensis, L.) Peel Flour in Biscuit Making

Sweet orange fruit (Citrus sinensis,L.) peels were dried to constant weight using oven, box solar and sun drying methods. The dried orange fruit peels were processed into flours and used to substitute 10, 20 and 30 % wheat flour (WF) in biscuits. The orange peel flours were analyzed for photochemical composition. The biscuits were analyzed for photochemical composition and evaluated for sensory properties. The content of flavanoids (0.48 mg/100g) of the solar dried orange fruit peel flour (SOFPF), saponins (0.73 mg/100g), tannins (0.91 mg/100g) and alkaloids (0.99 mg/100g) of oven dried orange fruit peel flour (ODOFPF) were higher than those of the sun dried orange fruit peel flour (SDOFPF). The carotenoids (0.32 mg/100g), flavanoids (0.38 mg/100g) of 30 % SDOFPF biscuit, saponins (0.33 mg/100g), tannins (0.59 mg/100g) and alkaloids (0.82 mg/100g) of the 30 % ODOFPF based biscuit were higher than those of the other biscuits. The 100 % WF biscuit (control), followed by 10 % SDOFPF biscuit had higher overall acceptability scores of 8.0 and 7.1, respectively than the other biscuits. The overall acceptability score of 5.5 for biscuit containing 30 % ODOFPF was the lowest.