Recovery of high-value bioactive phytochemicals from agro-waste of mango (Mangifera indica L.) using enzyme-assisted ultrasound pretreated extraction

Mangifera indica L. is an important tropical fruit having a high nutrient composition of dietary fiber, carbohydrates, vitamins, minerals, and polyphenols. Ultrasound-assisted extraction (UAE) and enzyme-assisted ultrasound extraction (EAUE) were used to optimize bioactive molecule extraction from the agro-industrial waste of mango peels. Both extraction strategies were adopted to deal with the extraction yield and environmental compatibility aspects. The mango peel extracts were pretreated using a combination of enzymes and ultrasound irradiation and used to extract bioactive phytochemicals. Results revealed that the highest total phenolic contents (33.56 ± 1.04 mg GAE/g fresh weight) were detected in mango peel extracts pretreated with 3.3% alcalase enzyme, pH 5.5 at 63 °C for 110 min and 90 Watt (UP) in EAUE, while the same set of optimized extraction conditions for UAE yielded the highest polyphenolics (25.64 ± 0.98 mg GAE/g). Mango peel extract pretreated under predefined optimized conditions (EAUE-1 coded extract) showed the highest trolox equivalent antioxidant capacity (TEAC) value (215.42 ± 1.21 mM TE/g). Likewise, the DPPH-scavenging capacity (1C50: 11.38 μg/mL) was also higher than the control. Characterization by high-performance liquid chromatography corroborated the abundant presence of vanillic acid and 4-hydroxy-3-methoxy benzoic acids (phenolic acids) in mango peel extract. In conclusion, EAUE appears as an efficient technique with broad-spectrum applications in extracting and recovering bioactive compounds from natural resources.