Phytochemicals, Antioxidant, Physico-Chemical and Sensory Properties of Yam-Based Cookies Produced from Flours of Five Yam Varieties

Abstract

The aspiration to reduce post-harvest losses of yams via the promotion of utilisation of the abundant readily available raw materials for industrial purposes and production of health-enhancing foods prompted this research. This work focused on evaluating the phytochemical, antioxidant, physicochemical and sensory properties of yam-based cookies produced from the flours of five yam varieties. Established standard procedures were used in all analyses. Results showed; Phytochemical compounds such as phenols, flavanoids, alkaloids and tannins were found present in the yam-based cookies in the range of 0.24- 0.37mg/100g, 0.26- 0.40 mg/100g, 0.6- 2.13mg/100g and 0.01- 0.17mg/100g. Saponin was not detected in all the yam flour cookies. Only a trace of 0.05 mg/100g was observed in wheat flour cookies (the control), Antioxidant activities of the yam-based cookies revealed that DPPH, FRAP, MCA, HRSA and SRSA ranged from 41.19-84.32, 0.29-0.95, 34.15-78.51, 29.64-69.54 and 24.13- 81.52 accordingly. Gluthanion was used as standard. The general trend observed was that, in all cases; sample HKC had the least antioxidant activities, OGC and ARC had higher antioxidant activities among the yam-based cookies, while GSH (the control) had the highest. The proximate values for Moisture, ash, crude fiber, crude protein, fat, carbohydrate and energy of yam-based cookies ranged from 7.31- 8.80%, 1.10 - 2.30%, 0.13 – 4.27%, 8.53-10.48%, 2.24 – 3.84%, 73.70-78.38% and 334.06-359.28 Kcal/100g. Physical properties of the Yam-based cookies such as diameter, width, thickness, weight, Spread ratio, spread factor and fragility ranged from 3.70-4.67 cm, 23.93-28.00 cm, 2.63-4.33cm, 5.16-9.67g, 0.83-1.64, 54.63-106.84 and 430.00-790.00g respectively. Cookies from all samples showed good physical quality features for the production cookies and biscuits. Sensory properties such as appearance, texture, crispiness aroma, taste and general acceptability of yam-based cookies ranged from 5.32-8.30, 6.48-8.44, 7.50-8.44, 6.36-7.68, 7.48-8.50, and 6.30-7.84 on a 9-point hedonic scale. Data from this study proved that it was feasible to produce acceptable cookies from the flours of the five yam varieties selected. Overall, samples GBC and ARC cookies competed favorably with the control-wheat cookies and are recommended for mass production. In Particular, sample ARC also combined good nutritional, phytochemical quality and strong antioxidant activities that could be of health benefits to consumers.