Chemical composition of biscuits supplemented with orange peel and pulp flours

Abstract

Sweet orange (Citrus sinensis) fruits were washed, peeled manually, the juice was extracted using kitchen juice extractor and the seeds were removed. The peels were separated from the pulps and sliced into thin slices of about 2 cm thick, sun dried separately till constant weight was achieved. They were milled and sieved to obtain orange peel and orange pulp flours, respectively. The orange peel and pulp flours were used to substitute 10% wheat flour. Biscuits were produced from the flour blends and 100% wheat biscuit was produced and evaluated for chemical composition (proximate analysis, mineral and phytochemical compositions). The results showed that the orange pulp biscuit was significantly higher (p < 0.05) in moisture and fibre, while orange peel biscuit was higher in ash. The pulp and peel biscuits had lower levels in fat, protein, carbohydrate and energy content. There were no differences (p > 0.05) in mineral content of the orange peel and pulp biscuits, though higher values were recorded for calcium and sodium when compared to 100% wheat biscuit. The orange peel biscuit had higher (p < 0.05) levels of all the phytochemicals (saponins, alkaloids, flavonoids, anthocyanins and carotenoids) assessed. Edible biscuits can be produced from blends of wheat and sweetorange peel and pulp flours which are sources of bioactive compounds that possess nutraceutical properties.