Abstract

W. Braide and R. N. Nwaoguikpe

Cocoyam is an edible root crop belonging to the family Araceae. It makes significant contribution both as root crop and vegetable in the diet of mainly Africans people and Nigerians inparticularly. The high percentage of starch was exploited in the production of ethanol. Two hundred grams (200 g) of mashed Colocasia esculenta, gelatinized in a pressure cooker was allowed to undergo two stage enzyme hydrolysis using bacterial alpha-amylase (Amylitic-TS) and fungal alpha-amylase (AMG) to produce fermentable sugar (wort). The hydrolysed liquor was inoculated with viable yeast cells, Saccharomyces uvarum, and yielded 12.9% ethanol after 7 days of fermentation. The pH and brix level (total soluble solids) of the fermenting broth dropped significantly from 4.50 to 3.82 and 15.0 to 2.0 respectively. This suggested that the saccharification process was effective. The reduced pH provided an enabling environment for optimum activity of the yeast. The sugar level decreased appreciably as the ethanol content increased from 0 to 12.9%. The decrease in the specific gravity from 1.0000 to 0.9830 could be attributed to the decrease in the brix level as the sugar in the broth was converted to ethanol.