Drying Phenomenon and Influence on the Anti Nutritional and Pasting Properties of Cocoayam (Taro)

Abstract

Aims: The presence of natural or synthetic compounds that interfere with the absorption of nutrients called antinutrients causing itching in the mouth has, resulted in the underutilization of cocoyam and therefore requires some processing methods to reduce these limiting factors. Effect of drying at different temperatures on the proximate composition, functional properties and anti-nutritional factors (ANFs) and investigation into moisture reduction pattern of cocoyam flour were therefore studied. Place and Duration of Study: Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria between June 2011 and March 2012. Methodology: Raw cocoyam (RC), cocoyam; dried at 60ºC (CF1), 70ºC (CF2) and 80 ºC (CF3) were grounded to fine flour and their proximate composition, antinutritional content and physicochemical properties were determined. Results: The flour samples have low bulk density values with samples dried at 60 and 70 ºC being the lowest which is significantly different from that of the other treatment. The flours have high water absorption capacity and high swelling power values with the flour dried at 70 ºC being highest and significantly different from the other samples which are not significantly different from each other. Crude protein was highest in CF1 and lowest in CF3. The difference in crude fat was significant (p<0.05) at the different temperatures used compared to RC. Contents of ANFs [tannins, phytate, oxalate, and saponin] were not significantly reduced by the drying temperatures adopted compared with the RC but was below the threshold limit. Conclusion: The results showed that the drying temperatures adopted enhanced the nutrients and physicochemical properties with no significant reduction in the antinutrients. This was suggested to be due to the low temperature treatments employed.