The Microbiology of Tella Fermentation

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Date

1990-06

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Addis Ababa University

Abstract

Jl'our major phases in Tella fermentation !'rere identified. In each phase, different microorganisms !'iere isolated and enumerated. Six genera of bacteria ~lGJ:'e identified. They \'lere: A!'.thrqbact~er, AcetobacteL, Last;obacilJY2., Baci),.Lu,!'!.. Proteus and l).chromopll.cte:r::. In addition t\oro genera of yeasts I Saccharom.yces and Rhodot orula, ,'rere ident ified, out of these Sacchar~ll!L9_e.§. ~/HS found to be responsible for tella fermentation. In addition to microbiological studies, chomical and physical characteristics of the four phases \'rere studies. In phase I (0-96 hr), the pH droped from 5.2 to Lf.73 at the end of this phase. 'l'here is a slight difference bet~reen temperature of fermonting material and the room temperature"- The total solid content, amount of re.ducing sugar and total carbohydrates ranging from 4.4% to 5. Lf9"lo, 4.04 to 12.0 mg/ml and 18.5-33.4 mg/m:). respectively. In phase II (96-144 hr), the pH decreased from 4.73 to 4.71. Likewise the temperature of the fermenting material increased from 21 00 to 2500 at the end of this phase. The total solid content, amount of reducing sugar,total carbohydrates and ethanol content ranged from 15.22 to 21.1%, 8.75 to 28.37 mg/ml, i}3.16 to <)8.08 mg/ml and o to 3.17% respectively. In phase III (1Lj.Lj. - 192), the pH fell from 4.75 to 4.67 at tho end to this phase. The temperature increased from 240 0 to 2700 at time 192 hr. The amount of total solids, reducing sugar, total carbohydrates and ethanol content ranged from 25.0 to 28.76, 5.2 to 14.83 mg/ml, 98.57 to 118 mg/ml and 2.77 to 5.13% respectively. In phase IV, the pH decreased from 4.58 to 3.34 at the end of this phase. The temp~rature also decroased from 24.600 to 21.6700. The total solid, reducing sugar, total carbohydrate and ethanol contents ranged from 4.3 to 11.73%, 2.35 to 5.2 mg/ml, 34.6 to 78.57 mg.ml and 4,3 to 5.13% respect ively at the ene. of period I ( 192 - 264 hr) of phase IV. In addition a comparison vms made between the laboratory brovred and locally collected tella samples with regard to microbial populations, chemicals and physical characteristics. The microorganisms res,?onsible for its fermentation and spoilage "rcre found to be similar.

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Biology

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