PROXIMATE COMPOSITION OF TANNIA (Xanthosoma sagittifolium) FLOUR AS INFLUENCED BY PRETREATMENT AND DRYING TEMPERATURE

Drying is an important operation in processing fresh tannia cormel into flour with better storability. Product characteristics and drying variables could affect the final product's quality and consumers’ acceptability. This study was therefore designed to investigate the effects of blanching time (5, 10, and 15 minutes) and drying temperature (60, 70 and 80°C) on selected proximate composition of oven-dried tannia flour. Response Surface Method (RSM) of 2 factors, 3 levels Historical Data Design (HDD) second-order polynomial model was adopted for the experimental design. Flour was produced from fresh and pretreated tannia cormels and proximate analysis of the flour samples was carried out using standard methods. Data obtained were statistically analyzed at 5% level of significance. Moisture content (wet basis), carbohydrate, protein, ash, crude fibre and fat content of the flour samples were within the ranges 4.43-12.74, 77.34-84.71, 2.22-4.22, 2.47-4.69, 0.34-2.50 and 0.63-3.72%, respectively. Samples dried at 60oC and blanched for 12.74 minutes had the best quality attributes with the optimum response values of 83.19% carbohydrate, 3.56% protein, 3.80% ash, 0.98% crude fibre and 1.96% fat with 7.01% moisture content. Extended blanching period is recommended to obtain high-quality flour with improved storage stability. Proper combination of drying temperature and blanching period that will result in desired proximate composition of tannia flour can be achieved based on the findings of this study