EFFECT OF DRYING METHODS ON NUTRITIONAL AND MICROBIAL PROFILE OF KOCHO AND BULLA FLOUR FROM ENSET (Ensete

Abstract

Enset (Ensete ventricosum) is a starchy perennial and multipurpose food security crop feeding over 20 million Ethiopians. Kocho and bulla paste are the two main processed products of enset with high moisture content. Attempts are being made at local scale to prepare dried kocho and bulla flours with the aim to make value added food products. However, standard methods for drying bulla and kocho and information on how drying methods influence nutritional and microbial characteristics of the two main processed enset products are lacking. The aim of this particular work was to study the effect of different drying methods on nutritional and microbial profiles of kocho and bulla focusing on physico chemical, nutritional and microbials profiles. Prior to drying, kocho and bulla paste were obtained from processed matured enset (Gena landrace) using innovative enset processing and fermentation technologies developed by Arba Minch University. Both kocho and bulla were dried using three drying methods: direct sun, solar and oven. The two products were milled and sieved with 1mm mesh size into fine flours and were subjected to physico chemical, nutritional, microbial and functional evaluations. The result for kocho flour showed a range of 9.32 - 12.67% moisture content, 3.11- 4.09 pH, 0.19 - 0.31% titratable acidity. Also, crude proteins ranged from 1.96-2.36%, crude fat from 0.42-0.59%, crude fiber from 2.93 - 3.37%, ash from 3.14 - 4.02% and carbohydrate from 77.95 - 81.93%. Microbiologically, kocho and bulla flours had 3.99 - 4.98 logcfu/g and 4.29 - 5.80 logcfu/g of lactic acid bacteria, 5.01-5.19 logcfu/g and 4.63 - 5.21 logcfu/g of total viable count, 2.11 2.34 logcfu/g and 2.12 - 2.52 logcfu/g of yeast and mould, respectively. Enterobacteriaceae was not detected in all samples. Nutritionally, bulla flour had 0.31- 0.65% protein, 0.28-0.6% fat, 0.29 - 0.60% fiber, 0.93 - 1.28 % ash and 86.15 - 90.43% carbohydrate. Solar drying had the lowest moisture content, pH and the highest carbohydrate and good functional properties compared to other drying methods. Thus, we conclude that solar drying is the most effective method for preserving the nutritional properties of both kocho and bulla flour. Further study should be conducted to evaluate the sensory qualities, pasting properties, anti-nutritional factors and metabolites