ANTIOXIDANT PROFILE AND BIOACTIVE COMPOUNDS FROM CAMU-CAMU AND JABUTICABA PEELS: IMPACTS OF DRYING AND EXTRACTION METHODS

Camu-camu and jabuticaba, fruits from the Myrtaceae family, are sources of bioactive compounds. Thus, this study evaluated the effects of dehydration methods (freeze-drying [L] and thermal drying [D]) on the antioxidant activity and the content of phenolic compounds of aqueous (A) and ethanolic (E) extracts from camu-camu (CC) and jabuticaba (CJ) peels, obtained via ultrasound-assisted extraction (UAE). Extracts at 2% (w/v) were prepared using UAE for 15 min at 40% amplitude and a 5-second on/off pulse cycle, employing a sonicator with a 3 mm probe and a frequency of 26 kHz. UAE extracts from fresh (F) peels served as controls. Total phenolic content was assessed using the Folin-Ciocalteu method, while total flavonoid content and antioxidant activity were evaluated via ABTS, DPPH, and FRAP assays. Results were subjected to analysis of variance and Tukey's test (p<0.05). Drying increased the concentration of bioactive compounds in extracts L and D compared to the control for both fruits. For camu-camu, the CCLA extract exhibited the highest reducing power in the FRAP (3,167.34 ± 66.4 µmol SF g^-1) and ABTS (1,298.23 ± 27.6 µmol TE g^-1) assays, whereas CCLE showed the highest total phenolic content (121.90 ± 1.6 mg GAE g^-1) and DPPH activity (888.58 ± 108.6 µmol TE g^-1). Camu-camu flavonoid levels in the CCDA (1.474 ± ​​0.075 mg QE g^-1) and CCLA (1.463 ± 0.056 mg QE g^-1) samples were similar. For jabuticaba extracts, solvent polarity was a determining factor. The highest ABTS activity was observed in CJLE (2,354.4 ± 41.6 µmol TE g^-1) and CJDE (2,057.46 ± 70.02 µmol TE g^-1) — compared to CJLA (198.3 ± 8.4 µmol TE g^-1) — along with the highest total phenolic content (77.39 ± 1.4 mg GAE g^-1). The combination of freeze-drying and ethanolic extraction (CJLE) achieved the highest flavonoid content (1.91 ± 0.08 mg QE g^-1). Thermal drying preserved a significant level of bioactive compounds, with CCDA showing 2,028.33 ± 102.05 µmol TE g^-1 (FRAP) and CJDE showing 71.64 ± 1.38 mg GAE g^-1 (Folin-Ciocalteu), demonstrating the method's viability. CCFA and CJFA exhibited flavonoid contents of 1.115 ± 0.050 and 1.528 ± 0.086 mg QE g^-1, respectively. Freeze-drying proved efficient in preserving bioactive compounds in camu-camu and jaboticaba peels, yielding significant concentration values ​​when ultrasound-assisted extraction was performed in an aqueous medium for the former and an ethanolic medium for the latter. These results highlight the high potential of these co-products for the development of functional ingredients and other food applications.