Effect of processing conditions on phenolic compounds, antioxidant activity, and anthocyanin retention in jabuticaba-based sticks

Jabuticaba (Plinia cauliflora) is a Brazilian native fruit rich in phenolic compounds and anthocyanins, especially in the peel. However, its short shelf-life limits commercialization, making the development of value-added products an attractive alternative. This study investigated the effect of different processing conditions on the retention of phenolic compounds, antioxidant activity, and anthocyanins in jabuticaba-based sticks, aiming to identify the formulation that best preserves these bioactive compounds. Seven formulations containing 5% jabuticaba peel flour (JPF) were produced. Formulation F1 contained 9% fresh jabuticaba pulp, while F2 contained 9% fresh jabuticaba peel. Formulations F3 to F7 were immersed in a syrup prepared from crushed jabuticaba fruits and removed after 8, 6, 4, 2, and 0 min, respectively. After immersion, the sticks were coated with crushed jabuticaba peel and dried at 40 °C. Ground samples (0.5 g) were extracted with 70% ethanol by ultrasound-assisted extraction. Total phenolic content (TPC), antioxidant activity (FRAP), and monomeric anthocyanins were determined using the Folin-Ciocalteu, ferric reducing antioxidant power, and pH differential methods, respectively. All analyses were performed in triplicate. JPF exhibited high levels of bioactive compounds, with 4,654.88 mg GAE/100 g of TPC, 74,146.76 μmol TE/100 g of FRAP, and 960.33 mg/100 g of monomeric anthocyanins, confirming its potential as a functional ingredient. Significant differences (p < 0.05) were observed among the stick formulations. TPC ranged from 929.12 to 1,398.22 mg GAE/100 g, with F3 showing the highest value, followed by F5 and F7. Antioxidant activity exhibited the same trend, varying from 15,697.89 to 24,940.42 μmol TE/100 g, indicating a strong positive relationship with TPC. Although F3 exhibited the highest phenolic content and antioxidant activity, monomeric anthocyanins were detected exclusively in F5 (47.01 mg/100 g). This result suggests that an intermediate immersion time (4 min) provided the optimal balance between anthocyanin incorporation and thermal stability. Longer immersion times likely promoted anthocyanin degradation, whereas shorter immersion times may have limited pigment diffusion into the sticks. These findings demonstrate that processing conditions play a decisive role in preserving jabuticaba bioactive compounds. While prolonged immersion maximized phenolic extraction and antioxidant activity, an intermediate immersion time was essential for anthocyanin retention. Therefore, F5 represents the most promising formulation for producing functional jabuticaba-based sticks with enhanced nutritional and antioxidant properties.

Acknowledgments to Agronomic Institute – IAC; Surreal Bisks