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The impact of power ultrasound application on physicochemical, antioxidant, and microbiological properties of fresh orange and celery juice blend

Ruiz-De Anda, Daniela, Ventura-Lara, María Guadalupe, Rodríguez-Hernández, Gabriela, Ozuna, César
Journal of food measurement & characterization 2019 v.13 no.4 pp. 3140-3148
antioxidant activity, antioxidants, ascorbic acid, bioactive compounds, celery, color, flavonoids, oranges, pH, phenols, sonication, titratable acidity, total soluble solids, ultrasonic treatment, ultrasonics, vegetable juices
The aim of this work was to study the effect of power ultrasound (PUS) application on physicochemical, antioxidant, and microbiological properties of a juice blend from oranges and celery stalks. Juice samples were sonicated in an ultrasonic bath (20 kHz, 5.57 ± 0.87 kW/m³, 20 ± 5 °C) at different sonication times (0, 15, 30, 45, 60, 75, and 90 min). Samples were stored in the dark for 24 h at 4 °C and subsequently analyzed. Significant (p < 0.05) positive effects of PUS treatment on bioactive, antioxidant, and microbiological properties of the treated juice blend were observed even after the shortest sonication time (t = 15 min), with best results being obtained for 45 min PUS treatment (13% increase in total phenols to 280.35 ± 4.51 mg GAE/100 mL; twofold increase in total flavonoids to 3.16 ± 0.11 mg EQ/100 mL; 17% increase in antioxidant activity to 24.46 ± 0.02 mg TE/100 mL). Importantly, ascorbic acid content (37.78 ± 7.24 mg AA/100 mL) and some important physicochemical properties of the juice (total soluble solids, pH, titratable acidity) were unaffected by PUS. However, PUS-induced changes in color attributes were strongly correlated (|r| > 0.60; p < 0.001) with an increase in bioactive compound content and antioxidant activity. Also, the 53% increase in cloud value (1.70 ± 0.03) points to an increased stability of the PUS-treated juice blend. Therefore, ultrasonic treatment could represent a viable non-thermal technology for microbial inactivation in fresh orange and celery juice blend while increasing its stability and preserving its bioactive properties and quality attributes.