Extraction of mangiferin and pectin from mango peels using process intensified tactic: A step towards waste valorization

Abstract

Simultaneous extraction of mangiferin and pectin from the waste mango peels was attempted with the aim of reducing the number of processing steps, minimizing the operation time and avoiding the requirement of harsh acids. Microwave-assisted extraction has been employed along with different hydrotropes (sodium cumene sulfonate, sodium salicylate, and sodium p-toluene sulfonate) and methanol with varying concentrations. The highest yield of mangiferin (10.43 mg/g) was attained using sodium cumene sulfonate at 80 W microwave power, 10 min time, 0.5 M concentration, 80 °C temperature and 1:50 g/mL solid-liquid ratio. The mangiferin recovery was 20 % higher using hydrotropic solution in comparison to methanol (50 %, v/v). The hydrotropes have concurrently extracted pectin (25.38 %, w/w), which was not possible using methanol. Thus, the incorporation of hydrotropes has led to the avoidance of acidic solution for the recovery of pectin. Pectin has a higher methoxy content (∼ 74 % degree of esterification) and a higher percentage of D-galacturonic acid. The extraction time was further reduced in the range of 50–70 % by embedding sonication with microwave-assisted extraction. Moreover, the extract has exhibited good antioxidant activities (> 70 % DPPH and> 90 % ABTS). A symbiotic effect of hydrotrope, microwave and sonication has resulted in the simultaneous extraction of mangiferin and pectin along-with better processing conditions thereby providing a sustainable option which can be explored at a higher scale. In addition, the present study has presented a judicious utilization of mango waste.