Traditional processing, microbial and physicochemical changes during fermentation of malwa

Abstract

A survey was conducted to characterise production methods of malwa; a Ugandan traditional fermented millet beverage, in four divisions of Kampala district using a questionnaire. Lactobacillus and Lactococcus spp and coliforms were enumerated in the raw materials and during fermentation using standard microbiological methods. Changes in chemical parameters were determined using standard methods. Similarities in production methods were observed among the malwa producers. All producers germinated millet grains (2-3 days) to make green malt. The germinated grains were sun-dried for 2-3 days. Moistened millet flour was subjected to solid state pit fermentation for one week to produce acidified fermented dough. The acidified fermented dough was roasted over an open fire to produce roasted acidified dough. The duration of fermentation of malwa varied between 2 and 4 days. Only 5% of the producers practiced back slopping. Producers (90%) reported that consumers preferred sour malwa. Lactobacillus and Lactococcus spp numbers in the sour dough, roasted sour dough and green malt varied between 3.48 and 5.38, 2.02 and 2.60, and 4.45 and 6.25 log cfug –1 respectively. Coliforms in sour dough, roasted sour dough and green malt varied between 1.36 and 5.53 log cfug –1 . Lactobacillus spp increased from 2.73 to 6.60 log cfu mL –1 whereas Lactococcus spp increased from 2.67 to 6.22 log cfu mL –1 during 72 h of fermentation. The greatest increase in numbers was observed during the first 24 h. Coliforms decreased from 2.80 to 1.19 log cfu mL –1