Microbiological and Physicochemical Study of Azo, A Traditional Fermented Condiment Prepared from Sorghum and Leaves of Endod (Phytolacca Dodecandra) in Kafta Humera, Tigray Regional State.
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Date
2015-06-04
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Addis Ababa University
Abstract
Azo is a traditional fermented condiment prepared from cereal flour and leaves of endod in northwest Ethiopia Tigray regional state, particularly Kafta Hmera. The fermentation process is carried out spontaneously in traditional smoked container calabash or earthen pot. The objective of this study was to examine the physicochemical and microbial feature of Azo and identifies the predominant microorganisms those carried out fermentation. To this end, four ready to consume azo samples were collected from different households of Kafta after 6 days of fermentation and one sample was prepared in the laboratory. Samplings for laboratory prepared azo were taken every 24 hours interval for seven days; other two samples were taken from fifteen, and thirty days of fermentation to study the physicochemical and microbial profiles during fermentation. Accordingly, the pH was drastically dropped from 6.58 to 3.75; with 6-fold increase in titratable acidity (TA); with progressive increase in water content (from72.23 to 80.60%); protein (from 3.28±0.04 to 4.87%). The result also showed that decrease in fat (from 4.19 to 3.75%), carbohydrate (from 17.45 to 8.6%) and ash content (from 2.86 to 2.11%) from 0 to 6 days of fermentation. At the first six to seven days of fermentation sharp increase in lactic acid bacteria (LAB) from 3.35 to10.49 and 3.68 and aerobic mesiophilic bacteria (AMB) count from 3.68 to 10.13 log of CFU/g were observed. Whereas, yeast increased slightly up to second day of fermentation and after 5th day of fermentation they were
disappeared. The total coliforms (TC) and faecal coliforms (FC) were only detected at first two and three days of fermentation and Salmonella was not detected throughout the fermentation period. Based on morphological, physiological and
some biochemical tests, a total of 42 LAB from azo were identified into five genera; Lactobacillus (52%), Pediococcus (21%) Lactococcus (10%), Leuconostoc (10%), Enterococcus (5%) and one unidentified genus (2%). In terms of occurrence throughout the fermentation, Lactobacillus and Pediococcus were the dominant lactic acid bacteria. Based on the results it can be conclude that fermentation shows good improvement in cured protein content and microbial safety of the product.
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Keywords
Azo, Fermentation, Homofermentative Lactic Acid Bacteria, Kafta, Microbial Load, Protein Content, Titratable Acidity