INFLUENCE OF EXTRACTION SOLVENTS ON THE TOTAL POLYPHENOL CONTENT AND ANTIOXIDANT ACTIVITIES OF THE PULP AND PEEL OF MATURE ROASTING BANANAS (Musa acuminata) AAB - GONJA

Four solvent systems: acetone, ethanol, and methanol with varying proportions of distilled water, were used to obtain extracts from the pulp and peel of mature roasting banana variety (Musa acuminata, genotype AAB) locally known as Gonja in Uganda. The determination of the extraction efficiency of the solvent systems was obtained through evaluation of the corresponding extracts’ Total Phenolic Content (TPC) and Antioxidant Activities (AA) using diphenylpicryl-hydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP) assays. All acetone solvent systems gave higher yields of extracted polyphenol content in comparison to other solvent systems except for the 90% ethanol solvent system (pulp = 55.33±6.49 and peel = 231.95±6.12 GAE mg/ g (dwb) with acetone (50%) giving the highest yield of total polyphenol content (66.82±6.45 and 264.14±5.33 GAE mg/ g (dwb) for both Gonja pulp and peel extracts respectively. For ethanol and methanol solvent systems, the yield of extracted polyphenol content increased with decreasing water fraction (50% > 70% > 90%) while a reverse trend was observed for the acetone solvent system (50% < 70% < 90%) and there were significant differences between the amount of polyphenol compounds extracted by the different solvents at various concentrations and for the banana parts. Results for antioxidant activity as measured by FRAP revealed that there are significant differences between the FRAP values by acetone at all the studied concentrations but the FRAP values for methanol and ethanol were not significantly different for concentrations of 50 and 70%. The results for antioxidant activity as measured by DPPH revealed that there are significant differences between the DPPH values for extracts from all the three solvents at concentrations of 50% and 70% but not at 90% concentration. The results also revealed that there were significant differences between the DPPH values of the extracts by the different solvents for the different banana parts.