Effect of processing on the proximate, functional and anti-nutritional properties of cocoyam (<i>Xanthosoma Mafafa</i> (Schott)) flour

Abstract

Xanthosoma mafafa (schott), an underutilized cocoyam tuber, was evaluated for the nutrients, functional and antinutrient properties of the flour as affected by processing treatments. The proximate, functional and anti-nutritional properties of the processed flour showed significant (p<0.05) variations. The proximate results ranged as follows: protein (5.30-6.80%), fat (0.45-1.40%), fibre (1.70-2.40%), ash (1.50-2.40%), moisture (6.50-9.40%) and carbohydrate (80.56-81.35%) respectively. Unprocessed flour had higher values of protein, and crude fibre, while boiled and blanched flour samples had lower values of protein, crude fat, crude fibre and ash. In contrast, there was significant increase in the fat and ash contents of the roasted flour (1.40 and 2.40%). The functional property values ranged as follows: bulk density (0.59-0.71 g/mL), water absorption capacity (3.30-4.80 mL/g), oil absorption capacity (1.60-2.90 g/mL), swelling index (1.26-2.0 mL/mL) and gelatinization temperature (65.25-80.25⁰C) respectively. Blanched and boiled flour showed low values of bulk density (0.59 and 0.63 g/mL), but higher values of water absorption (4.80 and 4.80mL/g) and oil absorption (2.75 and 2.90 mL/g) capacities than other processed flour, while the swelling index (2.0 mL/mL) and gelatinization temperature (80.25⁰C) of the unprocessed flour were significantly (p<0.05) higher. For the anti-nutritional factors (oxalate, phytate, flavonoids, tannin, saponin and phenol), the results showed that boiling and microwave flour had lower values of anti-nutritional factors, whereas, the unprocessed flour had the highest value than the processed flours irrespective of the processing method. The data obtained in this study show that X. mafafa (schott) processed flour can play important roles in boosting human nutrition and may help reduce food insecurity and hidden hunger associated with under-utilization of some staple crops which are rich sources of nutrients and phyto-nutrients, and in addition to the functional roles the flour can play in some technological applications.

Keywords: Cocoyam, processing treatments, proximate composition, functional properties, anti-nutritional content