Quantification of Caffeic Acid as Well as Antioxidant and Cytotoxic Activities of Ucuuba (Virola surinamensis) Co-Product Extract to Obtain New Functional and Nutraceutical Foods

Ucuuba (Virola surinamensis) is a fruit of Amazonian origin with anti-inflammatory, nutritional, and phenolic substances. This study aimed to prepare and characterize the ucuuba co-product extract as well as to evaluate its antioxidant and cytotoxic activities, proximate composition, and water activity. For this purpose, the co-product and its extract were analyzed by Fourier-transform infrared (FTIR) spectroscopy, and their thermal behavior was investigated by thermogravimetry (TG). The ucuuba co-product extract was also evaluated for its contents of total polyphenols and flavonoids, antioxidant activity by the DPPH and ABTS assays, and cytotoxicity in normal J774.A1 macrophages by the MTT technique. The co-product proved to have important macronutrient contents from a nutritional point of view, i.e., 11.67 ± 0.731% fiber, 16.67 ± 0.36% lipids, 38.32 ± 0.19% proteins, and 30.56% carbohydrates, as well as low moisture content (6.73 ± 0.05%) and water activity (0.403). FTIR spectra showed characteristic absorption peaks of phenolic compounds. The ucuuba co-product (pressed seeds) and the extract obtained from the ucuuba seed co-product were stable at around 100 °C and showed two mass loss events typical of natural products. The extract contained total polyphenols and flavonoids amounting to 806.45 mg/100 g and 62 mg RE/100 g, respectively, and its antioxidant activity according to the DPPH and ABTS assays was 374.33 and 258.15 µM Trolox/g, respectively. Caffeic acid was identified as an abundant phenolic compound (5.17 µg/mL) by high-performance liquid chromatography (HPLC-DAD), and its quantification method was validated. Furthermore, there was no cytotoxicity in the macrophage cell line at concentrations up to 100 µg/mL. These results indicate that the ucuuba co-product could be reused to develop new functional and nutraceutical foods.