Traditional alcoholic beverages of Tanzania: production, quality and changes in quality attributes during storage

Abstract

Traditional alcoholic beverages of Tanzania play an important role in the daily social, economic, nutritional and cultural life of the people. Production, quality and changes in quality attributes during ambient temperature storage were investigated in traditional Tanzanian beers (Mbege and Komoni) and wines (Mnanasi, Wanzuki and Mofru). The quality attributes of the alcoholic beverages indicated that pH levels were in the range of 4.15-4.20 and 3.9-5.5 for the beers and wines respectively. Total, fixed and volatile acidity in the beers were in the range of 0.41-0.62, 0.28-0.38 and 0.06-0.09g/100 mL respectively while in the wines acidity levels were in the range of 0.23-0.66, 0.13-0.33 and 0.05-0.06g/100 mL for the total, fixed and volatile acidity respectively. Concentration of total solids in the beers ranged between 7.00 and 12.80 Brix while in the wines ranged between 3.45 and 6.65 Brix. Specific gravity of the beers ranged between 1.0097 and 1.0374 while for wines the specific gravity was lower, ranging between 0.9971 and 0.9989. Alcohol concentration was higher in wines (range 3.84-9.75g/100 mL) than in beers (range 1.72-2.76g/100 mL). Storage of the beverages under ambient temperatures for various lengths of time resulted in significant (P < 0.05) increase in total acidity, volatile acidity and alcohol content and decrease in the total solids and specific gravity. Mbege and Komoni beers indicated the highest rates of deterioration with total acid production rates of 0.3774g/100 mL and 0.0914g/100 mL per hour respectively. Wines were more stable during storage than beers, with Mofru wine being the most stable. The rates of total acid production per hour were Mnanasi (0.0196g/100 mL), Wanzuki (0.0047g/100 mL) and Mofru (0.0005g/100 mL). Use of low brewing technologies involving uncontrolled fermentation, unsanitary conditions and use of rudimentary equipment for processing, packaging and storage resulted in beers and wines of low quality and short shelf-life. To foster commercial exploitation of the products, there is a need to develop appropriate small and medium-level brewing technologies that will improve the quality of the traditional alcoholic beverages and extend their shelf-life through hygienic and controlled processing, packaging, and storage.