Development of a green nutraceutical product from an ultrasonication-assisted solvent extract having antioxidant synergy among melatonin-serotonin-l-tryptophan from gamma-irradiated-cum-senesced plantains (Musa paradisiaca)

Development of nutraceutical products from agricultural crop waste is a vital and innovative approach to food waste valorization and in addressing sustainability challenges. The present study successfully developed a value-added antioxidant-rich product from gamma-irradiated (at 0.6 kGy)-cum-completely senesced (sensorially rejected) green plantains by ultrasonication-assisted solvent (green) extraction. Judicious choice of the extraction solvent(s), the extraction process parameters, their ranges of operations, and their optimization using statistical tools, namely, central composite rotatable design and response surface methodology, was conducted to obtain two distinct extracts from the plantains: one with the maximum extractable yield of phytomelatonin (7.15 µg/g plantain D.W); while the other having a synergistic consortium of the antioxidant triad-melatonin (3.31 µg), serotonin (2.45 µg), and l-tryptophan (1.84 µg) per g plantain D.W. Subsequently, the non-thermal technology of freeze-drying was employed to convert the extract into a dry-solid form without affecting the concerned light-and-thermosensitive antioxidants; and further, a deliverable form (containing 32.98 µg, 40.59 µg, and 43.07 µg of l-tryptophan, serotonin, and melatonin, per g plantain powder D.W, respectively) of the same was developed in the form of small round tablets. An in vitro release kinetics study of l-tryptophan, serotonin, and melatonin from the tablets in two gut-simulated buffers (of varying pH) showed considerable releases of 97.78%, 24.33%, and 83.78%, respectively, in buffer with pH 1 after 50 min, and 90.41%, 95.10%, and 97.71%, respectively, in buffer with pH 7.4, after 60 min. The final deliverable in tablet form can be regarded to be a truly antioxidant-rich ‘green’ nutraceutical product, especially rich in a synergistic consortium of l-tryptophan, serotonin, and melatonin.