An eco-friendly pressure liquid extraction method to recover anthocyanins from broken black bean hulls

This study aimed to recover the anthocyanin-rich extract from broken black bean hulls by pressurized liquid extraction (PLE) and to study their chemical stability, inhibition capacity toward carbohydrate-enzymes and application in gelatin. A Box-Behnken design (BBD) coupled to response surface methodology (RSM) was applied in order to maximize the anthocyanin extraction conditions. Optimum PLE conditions obtained were ethanol: citric acid solution 0.1 mol L-1 (30:70, v/v), a flow rate of 4 mL min-1, and 60 ?C. Delphinidin-3-glucoside was the main anthocyanin quantified. The PLE crude and purified anthocyanin-rich extracts inhibited ?-amylase (IC50: 0.52 and 2.85 mg mL-1) and ?-glucosidase (0.03 and 0.15 mg mL-1) enzymes, respectively. The PLE anthocyanin-rich extracts showed higher stability in low temperatures and in the absence of light. Besides, the application in gelatin provided a natural color and supplementation with antioxidant compounds. Overall, anthocyanin-rich extract obtained from black bean by-product using an eco-friendly PLE method shows potential as natural colorant and supplement. Industrial relevance: PLE method is an emerging technique that performs fast and efficient extractions under high temperature and pressure conditions. The association of green technologies with green solvents makes PLE an eco-friendly technology. This article provides information about the extraction of anthocyanin-rich extracts from the broken black bean hulls by green PLE process under optimized conditions. The process allowed to obtain antioxidant-rich extracts with high application potential in food, supplements, and pharmaceutical industries.

Automated summary

This study aimed to extract anthocyanin-rich extract from broken black bean hulls using PLE method, which showed good inhibition capacity toward carbohydrate-enzymes, chemical stability, and application potential in gelatin. The extracted anthocyanin-rich extract demonstrated potential as a natural colorant and supplement in food, supplements, and pharmaceutical industries. The PLE method is considered eco-friendly and efficient in extracting antioxidant-rich extracts with high application potential.