Ultrasound-Assisted Extraction of Semi-Defatted Unripe Genipap (Genipa americana L.): Selective Conditions for the Recovery of Natural Colorants

Abstract

Ultrasound-assisted extraction (UAE) of semi-defatted unripe genipap (SDG) using supercritical CO2 was performed to enhance the recovery of natural colorant iridoids genipin and geniposide. There are currently few natural sources of iridoids, and their application as colorants is scarce. The UAE resulted in extracts with blue and green colors using water and ethanol, respectively. The highest global yield and genipin content was recovered with water, and the geniposide was significantly recovered with ethanol. With water at 450 W, the UAE raised the maximum global yield (25.50 g/100 g raw material). At 150 W and 7 min, the maximum content of genipin (121.7 mg/g extract) and geniposide (312 mg/g extract) was recovered. The total phenolic content (TPC) and antioxidant capacity with the oxygen reactive antioxidant capacity (ORAC) assay were also high in aqueous extracts. Ethanolic extracts showed high ferric-reducing ability antioxidant potential (FRAP) values. UAE showed an efficient and fast method to obtain different extracts’ fractions from SDG, which have a wide spectrum of applications, especially as natural food colorants.