EFFECTS OF MALT TYPE AND FERMENTATION DURATION ON THE PHYSICOCHEMICAL AND MICROBIAL PROPERTIES AND SENSORY ACCEPTABILITY OF TELLA: AN ETHIOPIAN FERMENTED BEVERAGE

Abstract

Tella is among the fermented alcoholic beverages that are made from cereal grains and prepared traditionally on a small scale, typically for local consumption in Ethiopia. Hence, it is important to modify its preparation method through controlled fermentation and maintain its shelf life. This study aimed to investigate the effects of malt type and fermentation duration on the physicochemical properties, microbial profile, and sensory acceptability of tella. The experiment was conducted in a full factorial design (3x3) of two factors: the types of malt with three levels (barley, wheat and sorghum malt) and fermentation duration (48, 72, and 96 hours) after difdif phases of tella preparation. The physical properties such as geometric mean diameter, sphericity, thousand kernel weight, bulk density, angle of repose, and malt quality parameters of barley, wheat and sorghum such as germination energy, malting weight loss, moisture contents, friability, and malt extract were studied. The physicochemical properties of tella were significantly (P<0.05) affected by malt type and fermentation duration. For the sample made from wheat malt and 72 hours of fermentation, these parameters have been determined: pH, alcohol content, titratable acidity, total soluble solids, specific gravity, and color value were found to be 4.56, 7.14% (v/v), 0.84%, 5.20%, 1.0028% and 60.70 EBC, respectively. Accordingly, the pH, TSS, and specific gravity were decreased while the alcohol content, titratable acidity, and color value were increased throughout the fermentation time. The microbial profile: 7.10 log CFU/mL yeasts, 7.14 log CFU/mL LAB, and 5.35 log CFU/mL TAMB were also assessed, and sensory acceptability scores of 6.73, 6.58, 6.66, and 6.66 on a scale of 7 points for color, aroma, taste, and overall acceptability, respectively, were recorded. These values were compared and found to be tolerable with previous literature, along with high sensorial acceptability. Therefore, the tella prepared from wheat malt and harvested after 72 hours of fermentation was the most acceptable and might be recommended for consumption. Furthermore, tella made from different malts exhibited good and positive sensory acceptability during 30 days of storage in a refrigerator (4°C), as rated by panelists. Generally, this study gives a direction for future research outputs for producing tella toward expanding its production, standardizing and commercializing it on large markets