Subcritical fluid extraction of antioxidant compounds from soybean seed coats (Glycine max (L.) Merr.)

BERGESSE, ANTONELLA ESTEFANIA; VELEZ, ALEXIS RAFAEL; RYAN, LILIANA CECILIA; NEPOTE, VALERIA

BRITISH FOOD JOURNAL (1966)

EMERALD GROUP PUBLISHING LIMITED

Año: 2022

0007-070X

Purpose: The aim of this work was to evaluate the efficiency of subcritical conditions using different water–ethanol mixtures to recover antioxidant compounds from soybean seed coats (SSCs). Design/methodology/approach: SSCs were subjected to high temperature and pressure conditions, using ethanol–water mixtures as extractive solvent, to obtain phenolic and flavonoid compounds with antioxidant activity. A mathematical model, namely one-site desorption kinetic model, was used to describe the extraction kinetics. Findings: Temperature, solvent mass flow rate and solvent composition were studied, and the best extraction conditions were defined by a screening design. The maximum concentration of phenolics was obtained at 220 °C, 50% of ethanol and 2.5 g/min of solvent mass flow rate and a high antioxidant capacity toward different techniques was achieved. The one-site desorption kinetic model showed that before 30 min under optimal conditions, more than 90% of phenolics and flavonoids were recovered, a shorter extraction time than the commonly used at normal pressure and room temperature. Originality/value: The seed coat is a major by-product of soybean processing, and it only markets as a low value ruminant feed. To date, there are no reports on the extract phenolics from SSCs by means of this methodology. The extraction technique described in this study provides a potential alternative for extraction of bioactive compounds from SSCs. This study contributes to adding value to this industrial waste and, ultimately, to optimize the postharvest production chain of soybean grains.