Microbial Quality and Sensory Properties of Ogiri Produced from Watermelon (Citrullus lanatus) Seed

Abstract

The aim is to study the microorganisms involved in fermentation, their occurrence and the organoleptic properties of fermented watermelon (Citrullus lanatus) seeds. The watermelon seeds were dehulled, sorted, washed and boiled for 4 hours and fermented naturally for nine days. Microorganisms isolated from the fermenting watermelon seeds were Bacillus sp, Lactococcus sp, Pediococcus sp, Streptococcus sp, Micrococcus sp and Alcaligenes ps for bacterial, while the fungi obtained were Mucor sp, Rhizopus sp, Fusarium sp, Candida sp and Saccharomyces sp. The bacterial count increased from 4 x101 cfu/mL to 1.21 x 1010 cfu/mL while fungal count also increased from 8 x 101sfu/mL to 1.2 x 109sfu/mL during the period of fermentation. The pH and temperature increased from 6.3 to 8.7 and 29oC to 40oC respectively. The total titratable acidity decreased from 0.176% to 0.027%. The mean sensory characteristics value of fermented sample as scored by the panelist shows that the texture of the fermenting sample become softer as fermentation progressed. The aroma became more pungent with a strong ammonia odour responsible for the characteristic flavour and a darker colour of product. The overall acceptability of fermented sample was adjudged like very much while the sample bought from the market was adjudged like moderately.