Effect of Maturity and Optimized Solvent Extraction Conditions for Total Phenolic Content of Selected Genomically Diverse Banana Cultivated in Southeastern United States

Diabetes mellitus (DM) is a major cause of heart disease and stroke and the seventh leading cause of mortality in the United States. Natural plant based bioactive compounds offer appealing therapeutic strategy in ameliorating type 2 diabetes. Banana (Musa spp.) is a rich source of phytonutrients and antioxidants in particular phenolic compounds providing health benefits to consumers. Extraction efficiency of phenolic compounds may vary considerably dependent on solvent. Critical to future applications in food, nutraceutical and pharmaceutical industries requires optimization of extraction conditions for phenolic compounds. Stage of maturity may have a profound influence on phytonutrient content and bioactive compound extractability. There is a vital need for identification, determination and selection of phenolic enriched banana cultivars adaptable to Southeastern U.S. Therefore, collaborative research efforts between AL, FL, GA, HI and ND was initiated to accomplish stated objective in order to establish local niche market. Banana cultivars varying in genotype ‘FHIA’ (AAAB), ‘Hua Mua’ (AAB), ‘Kandarian’ (ABB), ‘Pisang Raja’ (AAB), ‘Saba’ (ABB) and ‘Williams’ (AAA) were harvested at full three quarter stage of maturity and room ripened at 20^oC and 95% RH (mature green, transition, ripe and over ripe). Three extraction solvents (methanol-water 50:50; acetone-water 50:50; acetic acid- acetone-water 1:50:49) were utilized to determine optimal extractability and recovery of total phenolic content in banana fruit pulp tissues. Extracts were analyzed for total phenolic content as determined by Folin-Ciocalteau method. Results indicate solvent effectiveness with regard to extractability of total phenolic content varied considerably. There were significant cultivar by maturity stage by solvent interactions (P ≤ 0.05). Acetic acid- acetone-water (1:50:49), provided the most efficient solvent with respect to cultivar and maturity stage. Moderate and lowest extractability of total phenolic content was observed for acetone-water (50:50) and methanol-water, (50:50) respectively. ‘Hua Mua’ (AAB), ‘Kandarian’ (ABB), ‘Pisang Raja’ (AAB) and ‘Williams’ (AAA) were observed highest in total phenolic content at ripe stage and in conjunction with acetic acid- acetone-water (1:50:49). ‘Pisang Raja’ (AAB) and ‘FHIA’ (AAAB) genotypes exhibited highest extractable total phenolic content. Acetic acid- acetone-water (1:50:49), provided the most efficient extraction solvent for recovery of phenolics from banana fruit tissue. Results suggest extracts from acetic acid- acetone-water may serve as a potential source of natural antioxidant for food, nutraceutical and pharmaceutical applications. Continuing research efforts will characterize the relationship between phenolic content and antioxidant activity and capacity in extracts of banana fruit pulp tissue.