Effect of Fermentation on the Nutritional Composition of Roselle Calyx Obtained from Ekiti and Benue State, Nigeria

Aim: The study was conducted to investigate the effect of fermentation on the nutritional qualities of Roselle calyx from two States in Nigeria.

Study Design: Roselle calyx was obtained from various locations and grouped into four: fermented naturally (FN), fermented with coconut husk ashes (FWCHA), Fermented with cocoa pod ashes (FWCPA), Fermented with Gmelina tree ashes (FWGTA), while unfermented samples served as control.

Place and Duration of Study: Fermentation of samples and isolation of microorganisms were carried out in the department of Microbiology while chemical analysis was carried out in Department of Chemistry, Federal University of Technology Akure, Ondo State, Nigeria between February 2015 and October 2016.

Methodology: Roselle calyx was fermented naturally (FN), fermented with coconut husk ashes (FWCHA), Fermented with cocoa pod ashes (FWCPA), Fermented with Gmelina tree ashes (FWGTA) separately for 72 hours. The nutrient, antinutrient and mineral compositions of raw and fermented calyx were determined using standard procedures.

Results: For samples obtained from Ekiti, protein and carbohydrate increased, crude fibre, fat and moisture decreased and ash content increased except in FN when compared to raw samples. Samples obtained from Benue showed an increase in protein, fibre and ash contents, an increase in carbohydrate content except for FWCPA while moisture and fat decreased significantly. Mineral content of samples obtained from Ekiti revealed a significant increase in sodium, calcium, magnesium and iron, a decrease in potassium and no significant difference in zinc content. Samples collected from Benue showed an increase in calcium, decrease in potassium except in FWCHA, magnesium content varied, and there was no significant difference in sodium and zinc. All antinutrients analyzed (phytate, glycoside, tannin, and phenol) decreased significantly in the samples obtained from both Ekiti and Benue state.

Conclusion: The nutritional composition and antinutrient content of the roselle calyx fermented with different methods varied significantly.