Caracterização físico-química e otimização de extração de compostos bioativos de butiá (butia eriospatha (mart. Ex drude) becc.) assistida por ultrassom utilizando solvente eutético profundo natural

Abstract

Butia eriospatha (Mart. ex Drude) Becc. is a palm species native to southern Brazil whose fruits stand out for their characteristic flavor and high concentrations of bioactive compounds, such as phenolics, flavonoids, carotenoids, and ascorbic acid. In the context of increasing interest in natural ingredients and sustainable processes, natural deep eutectic solvents (NADES) combined with ultrasound-assisted extraction (UAE) have emerged as promising alternatives to conventional organic solvents. This study aimed to perform physicochemical characterization and optimize the extraction of bioactive compounds from the pulp and peel of B. eriospatha using NADES and ultrasound. Ripe fruits were collected in Canoinhas (SC), selected, depulped, and divided into fresh samples for physicochemical characterization and dehydrated samples (60 °C/≈15 h), ground and standardized to 60 mesh for preliminary tests and subsequent extractions. Analyses included pH, total soluble solids, titratable acidity, color, and proximate composition. Extraction was conducted using Box–Behnken and 32 factorial designs. Extracts were evaluated for total phenolic content (TPC), total flavonoids (TF), total carotenoids (TC), and ascorbic acid (AA), as well as antioxidant activity (DPPH, ABTS, and FRAP). Quadratic models were fitted and applied to optimization through the desirability function. The optimized extract was also assessed for thermal (60–80 °C/120 min) and photochemical stability (0–96 h). The fruits showed typical characteristics of the species: average weight of 8.19–9.36 g, pulp yield of approximately 60%, total soluble solids of 11.3–11.8 °Brix, titratable acidity of 1.01 g/100 g, pH of 3.74, and proximate composition marked by high moisture (85.9%), carbohydrates (9.75%), and fiber (2.15%). In preliminary tests, the NADES ChCl–Gly (1:2) extracted about twice as many flavonoids compared to acidic NADES (8.85 mg QE/g), thus being selected for subsequent stages. In the factorial design, the NADES– UAE system yielded TPC values ranging from 122.97 to 166.45 mg GAE/g, TF from 5.20 to 8.32 mg QE/g, TC from 32.48 to 93.48 mg β-carotene/100 g, and AA from 4.30 to 5.47 mg/100 g, outperforming or equaling 50% ethanol (v/v). Antioxidant activity reached up to 114.59 mg TE/g (DPPH), 141.47 mg TE/g (ABTS), and 1013.48 mg TE/g (FRAP), indicating efficient extraction of both hydrophilic and lipophilic compounds. The optimized conditions (41 °C and 60 min) resulted in high overall desirability and strong agreement between predicted and experimental values. The optimized extract maintained nearly constant TPC (TPC/TPC0 ≈ 1.0) after heating at 60–80 °C for 120 min and continuous light exposure for up to 96 h, indicating excellent thermal and photochemical stability. This resistance suggests that the NADES acts as a stabilizing medium, preserving the chemical integrity of phenolics. Overall, the results demonstrate that the NADES ChCl–Gly/UAE system is an efficient, environmentally safe, and technically feasible strategy for extracting and stabilizing bioactive compounds from B. eriospatha. The high extraction efficiency, extract stability, and use of a biodegradable solvent reinforce the species’ potential as a natural source of functional ingredients and highlight the relevance of technologies aligned with green chemistry and the valorization of native fruit species.