Effect of thermosonication on some bioactive, sensory analysis and microbiological properties of yellow watermelon juice using response surface methodology

Abstract

In this study, the application of thermosonication, which is a moderate ultrasound process, on yellow watermelon juice and targeted optimization of the process conditions was completed using the surface response method. For this purpose, yellow watermelon juice was produced and thermosonication at different temperatures (30, 35, 40, 45 and 50 °C), different times (2, 4, 6, 8 and 10 min) and different amplitudes (40%, 45%, 50%, 55% and 60%) at 26 kHz frequency was applied to the samples. Total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (1,1-diphenyl- 2-picrylhydrazyl (DPPH), cupric reducing antioxidant capacity (CUPRAC)), and color values (L*, a* and b*) were evaluated for optimization of process conditions. At the same time, the differences between pasteurized yellow watermelon juice (PW) and a control (C) of untreated yellow watermelon juice were investigated. At the end of the optimization, microbial safety and sensory properties of the yellow watermelon juice samples were evaluated. As a result of the study, the maximum optimization values for the yellow watermelon juice, with thermosonication applied, were 38.3 °C, 5.6 minutes and 50.5 amplitude. At the end of optimization, CUPRAC (0.214 mg TEAC/mL), DPPH (0.123 mg TEAC/mL), total flavonoid content (41.28 mg CE/L), and total phenolic content (104.30 mg GAE/L) were determined. Thermosonication-treated yellow watermelon juice was found to be safe in terms of microbial values and was most preferred by panelists. As a result, thermosonication technology was successfully used for yellow watermelon juice production.