How Nutritional Composition of Commonly Consumed Vegetable Changes under the Influence of Fermentation

Document Type: Research Paper

Authors

Department of Agriculture, University of Ondo State, Nigeria

Abstract

In this research, spontaneous fermentation of some selected types of green leafy vegetables including Telfairia occidentalis (Fluted pumpkin leaf), Amarathus hybridus (Bush green), Pterocarpus mildbraedii (White campwood leaf) and Vernonia amygdalina (Bitter leaf) was performed for five days at ambient temperature. Changes in physicochemical properties of samples during fermentation were as below:
A steady increase was observed in titratable acidity (from 0.014 to 0.147) and temperature (from 27ºC to 34ºC) of all samples, while the pH value was decreased from 6.8 to 3.78. The abundance of isolated bacteria from the fermentation medium was 39.1% Bacillus spp., 26.1% Lactobacillus spp., 8.7% Staphylococcus spp. and Escherichia coli, 4.3% Pseudomonas spp, Serratia spp. and Citrobacter spp. Fermentation caused the mineral content of vegetables to increase and the vitamin c content to decrease. Niacin and thiamine content in A. hybridus and V. amygdalina was decreased, while a reduction was observed for T. occidentalis. The fiber content of V. amygdalina showed an increase from 10.97% to 14.55%, while this factor was decreased in other samples. It was also observed that the ash content of fermented and unfermented vegetables was increased from 12.50% to 23.28% and from 8.07% to 15.72%, respectively. The protein content of A. hybridus   and T. occidentalis increased after fermentation (25.65%-24.29%).

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