ULTRASOUND-ASSISTED EXTRACTION OF PHENOLIC COMPOUNDS FROM DEFATED CUPUAÇU SEEDS (Theobroma grandiflorum)

Seeds of cupuaçu fruits (Theobroma grandiflorum) are used to obtain edible oil with high-added value for the food and cosmetic industries. After oil extraction, the defated seeds are usually discarded, although they still have promising bioactive compounds composition with biological properties, especially regarding phenolic compounds. This study aimed to optimize the extraction of phenolic compounds from defated seeds, by response surface methodology (RSM), through ultrasound-assisted extraction (UAE) using ethanol/water mixture as green solvent. Additionally, the phenolic compounds were tentatively identified by high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD). During optimization, variations of the ethanol concentration in water (7.5–92.5%) and extraction time (6–34 min) in an ultrasound bath (frequency at 25 KHz) were carried out, and the contents of total phenolic compounds (TPC) and total flavonoids (TF) were the dependent variables. The TPC varied from 95 to 571 mg gallic acid equivalents/100 g, and TF varied from 10 to 391 mg catechin equivalents/100 g of defated seeds. The selected optimized conditions to extract phenolic compounds from the defated cupuaçu seeds, by UAE, were 6 min with 50% of ethanol in water (or 1:1, v/v), reaching 611 mg gallic acid equivalents/100 g and 379 mg catechin equivalents/100 g. The optimized extract was freeze-dried and revealed catechin and proanthocyanin B1 as the major compounds, but also showed the presence of gallic acid and epicatechin. These findings highlight the technological potential for the reuse of defated cupuaçu seeds to obtain extracts of bioactive compounds with promising biological properties to be used by the food, cosmetic and pharmaceutical industries by sustainable approaches.