Ethanol-modified supercritical CO2 extraction of cashew (Anacardium occidentale) nut testa

Cashew nut (Anacardium occidentale L.) testa, a by-product derived from cashew nut processing, is a valuable source of polyphenols with antioxidant properties. This study aimed to screen the extraction of cashew nut testa with supercritical CO2 and ethanol as a co-solvent. The impacts of various key operating parameters, including co-solvent concentration (5-20 %, v/v), temperature (40-60 degrees C), pressure (15-30 MPa) and extraction time (30-120 min) on the total phenolics content (TPC) and the antioxidant activity of the extract were investigated. The resulting extract from cashew nut testa exhibited high TPC and antioxidant activity values when employing a 15 % (v/v) ethanol co-solvent concentration, a temperature of 40 degrees C, a pressure of 25 MPa and an extraction time of 90 min. Under these conditions, the extract of cashew nut testa achieved TPC of 63.97 g<middle dot>kg(-1) on dry weight (DW) basis expressed as gallic acid equivalent and 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical-scavenging activity of 1522.72 mmol<middle dot>kg(-1) DW expressed as Trolox equivalent. Ethanol-modified supercritical CO2 extraction demonstrated promising potential as a sustainable approach for recovering the phenolic compounds from the cashew nut testa.