ASSESSMENT OF ABRIDGED MASHING OF THREE SORGHUM VARIETIES USING EXOGENOUS ENZYME MIXTURES .

Abstract

In this research, abridged infusion mashing trials were used to produce worts from three (3) sorghum varieties; SK5912, KSV8 and ICSV400 using a conglomerate of commercial enzymes to improve the wort properties as well as reduce the time for wort production. The grains were malted for six (6) days and several parameters related to malting were investigated.Thousand corn weight (TCW) was highest in ICSV400 (31.0g) while SK5912 and KSV 8 had (27.5g) and (25.0g) respectively. Moisture content (MC) was highest in KSV8 (10.5%) while SK5912 and ICSV400 had (9.4%) and (9.0%), respectively. Protein content was (10.4%) in ICSV400, (9.2%) in KSV8 and (8.5%) in SK5912. Germinative energy and germinative capacity ranged from 96% to 99% in all the varieties under this study. Malting loss was highest in KSV8 (18%) while SK95912 and ICSV 400 had (14%) and (16%) respectively, cold water extract (CWE) was highest in KSV8 (36%) while SK5912 and ICSV 400 had ((34%) and (32%), respectively. Hot water extract (HWE) was highest in ICS V400 233 oLKg -1, followed by SK5912, 230oLKg-1 and 228 oLKg-1 in KSV8. The Diastatic power (D.P.) was least in ICSV400 (18 oL) while SK5912 and ICSV 400 had (20oL) and (22oL), respectively. Worts were produced from malted and unmalted sorghum varieties using abridged infusion method, and subjected to various analyses according to IOB methods in order to determine their brewing properties. Such properties as carbohydrates, sugar analysis of various wort samples, total nitrogen, total soluble nitrogen (TSN), free alpha amino nitrogen (FAN) were determined. The worts from malted and unmated sorghum varieties were fermented for seven days and from the young beer fermented the following determinations were made: Percentage apparent extract, original extract, alcohol, apparent attenuation, and end degree of attenuation. In addition foam stability, PH, viscosity (CP)/mPa.s) free amino nitrogen (mg/l) and bitterness (BU) were determined. Finally the effects of addition of Neutrase (a protease) on the quality of worts derived from malted and unmalted sorghum varieties were investigated. The parameters involved included: specific gravity. PH, colour (EBC), carbohydrates (g%) and α-amino nitrogen FAN (mg/L). When the characteristics of fermented worts derived from malted sorghum varieties were compared with those from unmalted varieties it was discovered that worts from malted sorghum had higher values in both apparent and end degree of fermentation (%) – (80%) and (65.5%) against 79% and (64%), respectively. However worts from unmalted sorghum yielded more extract. Fermented worts 2 from malted sorghum varieties had lower values in alcohol content (3.38%) and foam stability 126 (EBC) as against (3.5%) and 129 (EBC). On the other hand fermented worts derived from unmalted sorghum had higher values in original gravity – (10.50%) – (10.65%) as well as higher viscosity values – (1.650 mPa.s) to (1.655 mPa.s). Other values were comparable except (FAN) which was higher in fermented wort derived from malted sorghum varieties. Significant differences were noted when the worts derived from malted and unmalted sorghum varieties were treated with additional neutrase (Protease). Worts derived from malted sorghum showed higher values in (FAN) which ranged from ((230 mg/L) to 260 mg/L as against 200mg/L to 230 mg/L in unmalted sorghum varieties. Carbohydrate values and specific gravity values, however, were lower in malted sorghum varieties than in unmalted varieties.