A water-based ultrasound-assisted extraction system to obtain natural blue colorant from Genipap (Genipa americana L.)

This study aimed to optimize the extraction of a blue colorant using ultrasound-assisted technology employing water as the solvent from genipap, an Amazon fruit. Process conditions were optimized by multiresponse analysis through the antioxidant activity by the ferric reducing antioxidant potential (FRAP) assay, the total phenolic content, and the b* and C* color parameters. The optimized conditions of 70 °C, 325 W, solid: solvent ratio of 1:40 (m/v), and time of 10 min were validated externally at a level of 90 % confidence. The composition of aqueous blue extract obtained under the greatest conditions was evaluated by ultra-performance liquid chromatography (UPLC). Besides, in vitro bioactivities such as digestive enzymatic inhibitions assays, and antiproliferative activity through human cells assays were evaluated. Genipin, geniposide, and other ten iridoids were identified in the aqueous blue extract. The natural colorant obtained presented the capacity of inhibiting enzymes involved in lipid and glucose digestion, suggesting a potential control of obesity and glucose levels in blood without showing cytotoxicity. Therefore, this study presented, for the first time, the optimal operational conditions to obtain a natural blue colorant from genipap in a green approach with interesting biological properties for the food and pharmaceutical industries.