PROXIMATE COMPOSITION AND INFLUENCE OF EXTRACTION TIME ON THE RECOVERY OF PHENOLIC COMPOUNDS FROM LICURI (Syagrus coronata)

The kernels of the licuri fruit (Syagrus coronata), a native palm tree from Brazil, are primarily used to obtain edible oil with valuable features for the food and pharmaceutical industries. Oil extraction generates a fibrous by-product known as press cake. Although often discarded or used as animal feed, the press cake may broaden the applications of this raw material due to its nutritional and bioactive potential, particularly its phenolic compounds. Therefore, this study aimed to investigate the influence of extraction time on the total phenolic content of licuri press cake and determine its proximate composition to explore its potential for new product development. The press cake was obtained by cold pressing and kindly provided by the COOPFRUT cooperative. Proximate composition was analyzed according to AOAC methods, yielding 11.2% ± 0.07 lipids, 30.0% ± 1.2 protein, 6.0% ± 0.06 moisture, 5.1% ± 0.2 ash, and 47.7% ± 0.6 carbohydrates (wet biomass percentage). To select the most efficient extraction solvent, a preliminary experiment was conducted using water, 50% and 80% ethanol, and 50% and 80% methanol combined with ultrasound-assisted extraction (Maxiclean 1400). Extraction efficiency was determined based on total phenolic content (TPC), quantified using the Folin–Ciocalteu method. Experiments were performed in triplicate, with three consecutive extractions per replicate and pooled supernatants, under identical conditions: 10 minutes, 30°C ± 5°C, and 40 kHz. Values ranged from 186 to 639.5 mg gallic acid equivalents (GAE)/100 g of defatted press cake. The 80% ethanol solution showed the best performance and was selected for subsequent experiments. The influence of extraction time was investigated by comparing 10, 35, and 60 minutes using 13 mL of solvent. Data were subjected to analysis of variance (ANOVA), followed by Tukey’s test at a 5% significance level. The highest TPC was observed after 10 minutes, reaching 782.13 ± 49.4 mg GAE/100 g of dry sample, followed by 35 minutes (666.23 ± 18.1 mg GAE/100 g) and 60 minutes (592.5 ± 57.8 mg GAE/100 g). The significant decrease in TPC with prolonged sonication indicates that longer extraction did not favor compound recovery under the conditions evaluated, possibly due to reduced stability under prolonged cavitation exposure and potential oxidation and degradation. In conclusion, licuri press cake exhibits promising nutritional composition, particularly as a protein source, and contains bioactive compounds. Among the solvents evaluated, 80% ethanol was the most efficient, while 10 minutes yielded the highest TPC. These results support further investigation into strategies for valorizing this by-product in the food industry.