Effect of drying method on functional properties of Yam (Dioscorea sp.) flour

The effect of drying method on functional properties of five different yam flour varieties namely, white yam, purple yam, yellow yam, water yam and three leaves yam were studied using oven, solar and sun drying method. The functional properties were determined using AACC approved method. Results revealed that White yam recorded wettability range of 173.22 - 181.31 secs while the purple yam had wettability range from 151.69 to 201 secs, the three leave Yam, had wettability range from 138.41 to 190.20 secs, the water yam and yellow yam recorded wettability range from 143.62 to 182.11 secs and 153.42 to 174.34 secs respectively. Result also indicated that white yam recorded water absorption capacity (WAC) range from 134.32 to 146.11, while purple yam had WAC range from 134.32 to 145.46; three leave Yam, water yam and yellow yam recorded from 129.56 to 138.11, from 133.58 to 163.21 and from 128.34 to 143.88 respectively. Furthermore, white yam, purple yam, three leave yam, water yam and yellow yam respectively recorded swelling power range from 11.84 to 12.63, from 11.14 to 11.82, from 11.28 to 12.66, from 12.19 to 12.38 and from 11.68 to 11.96. The three leave yam recorded the highest water absorption capacity which makes it likely to have least shelf life stability as compared to others because of the ability of absorbing water from a humid atmosphere. Results of the analysis of variance (ANOVA) on the effect of drying methods on the functional properties of the yam varieties showed significant difference at 5% and 1% probability level while the yam varieties did not show any significant different on the functional properties of the yam flour varieties.