Enhancing Qotcho fermentation process utilizing lactic acid bacteria inoculum: microbial kinetics and metabolism

Abstract

ABSTRACT Various studies revealed that quality of Qotcho relies on fermentation time, microbial activities, and varieties of Enset. Qotcho fermentation time is the most dominant factor. Several months to years of fermentation time is a challenging task for food security in Ethiopia. Shortening this long fermentation process was the primary aim of the study. Qotcho samples that have been previously fermented over various months were collected for lactic acid bacteria (LAB) analysis. While collecting the samples, temperature and pH of each sample were measured and recorded as 38 ± 2.3°C, 29 ± 1.5°C, and 25 ± 1.3°C, and 5.88 ± 0.8, 5.43 ± 0.6, and 4.69 ± 0.4, respectively. Using a serial dilution, selective media plates were innoculated and incubated at different temperatures for 5 days. On the second day of incubation, microbial growth was observed on each plate. A colony forming units (CFU) of 30–35 colonies of LAB were utilized to check fermenting performance of the microbes on different fresh Enset varieties at various temperatures for 36 days. Over 20 days of incubation, the pH of the media declined for all Enset varieties. From the 24th to the 28th fermentation time, the pH value for all varieties became constant (4.50) and sharply increased to 5.30 after the 28th. The quality of the Qotcho was determined to have similar characteristics and texture to the Qotcho that had been fermented for six months. The overall results showed that using LAB colony as a starter culture, about 26 days were enough to make Qotcho with good texture, odor, and color for consumption.