Optimization of Low-Cyanide Cassava Adjunct in Production of Ale Using Sorghum Malts at Varying Concentrations

Abstract

Optimization of low-cyanide cassava (TMS31/00110)adjunct for the production of ale using two varieties of sorghum malts was carried out at varying concentrations. The malted sorghum varieties and the processed low cyanide cassava adjunct were separately milled into moderately coarse size using Institute of Brewing method. Exogenous enzymes used include Bioprotease, Alpha Amylase (Termamyl), Beta Amylase (Promalt),and β-glucanase. Worts of different concentrations were obtained with the aid of upward infusion mashing system. Three hundred milliliters (300ml) of tap water was used to dilute 50g of the mixed concentrated grist for the ale samples. After complete saccharification from the mashing for about 2 1 / 2 hr, each mash was filtered to obtain clear sweet wort which was immediately subjected to various analyses. The clear worts obtained were boiled with hops for 45min, followed by cooling at15 o C for pitching. The pitched worts were fermented for 6 days. Caramel (5mls) was added to improve the colour of the liquors. Colour intensities were determined for ale using spectrophotometer according to European Brewing Convention method. Sensory evaluation tests were carried out on the ale samples using ten panelists, their judgment through questionnaires were statistically analyzed. The characterized worts showed that the original gravity ranged from 1045 to 1046 o  for prospective ale using sorghum CSR-02 Variety. The original gravity of ale was between 1044 to 1048 o P, with sorghum ICSV-400. The wort pH ranged from 5.21 to 5.29, viscosities from 1.08 to 1.12cP for prospective ale samples from sorghum CSR-02 and ICSV-400 varieties. For reducing sugars, maltoses were 178.30-196.20mg/l; glucoses were 109.30 and 120.30mg/l. The cyanide content reduced from 4.50mg/l to 0.00mg/l. The young ale beer obtained had the specific gravity ranging from 1016 to 1017 o P. pH ranged from 4.77 to 4.80; % alcohol of 3.69 to 3.99%. The apparent fermentability were 2.68 to 2.96% at 22 o C. The ale beer colour for the samples was 27 EBC. The Null Hypothesis was accepted since there was no significant difference among the samples produced at P≤0.05 level of significance.