Valorizing banana peels by extracting rutin with hydrated organic acids

Abstract

Bananas are a popular fruit worldwide and the fourth most important food crop. Banana peels, often discarded, contain valuable compounds known for their relevant biological activities, including rutin. In this study, organic acids, both in their pure and hydrated forms, were used as alternative solvents for rutin extraction. First, we assessed the ripeness of the bananas (green, semi-ripe and ripe), finding that ripe banana peels contained the highest rutin content. Then, COSMO-RS, a thermodynamic model based on quantum chemistry, was applied to determine the best organic acids for extraction, which were subsequently evaluated experimentally, with a 65 wt % acetic acid-water mixture yielding the best results (192 mg rutin/100 g DW). Next, extraction conditions were optimized using response surface methodology (RSM), resulting in 241 mg rutin/100 g DW at 27 °C, 80 min, and a solid-to-liquid ratio of 1:15. Finally, it was observed that the solvent could be reused for two cycles under optimal operating conditions without a significant decrease in rutin extraction efficiency. This study demonstrates the potential of mixtures of hydrated organic acids for the extraction of value-added compounds from natural sources, offering a solution to reduce food waste while contributing to a circular economy.

Keywords

• Solid-liquid extraction
• Food waste
• Alternative solvents
• Acid ethanoic
• Aqueous solutions
• Process optimization