Investigation of solvent type, concentration, extraction time and extraction temperature on total phenolic yield of selected Nigeria's indigenous legumes.

Abstract

This study evaluated the effect of extraction variables in a single factor experiment to optimize the recovery of total phenolics from lesser legumes namely, African oil bean (Pentaclethra mycrophylla Benth.), African yam bean (Sphenostylis stenocarpa) seed, African breadfruit (Treculia africana) and groundnut (Arachia hypogea) indigenous to Nigeria. Total phenolic was extracted using standard method with different solvents (acetone, ethanol and methanol), at different concentrations (20 – 100%, v/v), different extraction time (30 – 50 minutes) and incubated at different extraction temperatures (50 – 60oC). The results revealed that extraction variables significantly (p < 0.05) affected the total phenolic yield of the samples evaluated. Acetone used at 40% concentration (v/v) incubated at 50oC for 30 minutes gave the highest total phenolic yield in African breadfruit (221.28 mg/100 g) and groundnut (225.56 mg/100 g). In African oil bean, 60% acetone (v/v) incubated at 50oC for 50 minutes gave the highest total phenolic (326.89 mg/100 g) while, 100% acetone (v/v) incubated at 50oC for 30 minutes gave the highest total phenolics (196.94 mg/100 g) in African yam bean. This study suggests that for optimal recovery of total phenolics in lesser legumes the need to adopt the stated variables.