The Effect of Thermal Sonication of Bioactive Compounds and some of the Quality Parameters of Sour Cherry Juice Compared to the usual Pasteurization Method

The purpose of this study is to investigate the effect of thermal sonication in comparison with the usual pasteurization method on the bioactive compounds and their contents in sour cherry juice.The treatments were: controlled sample, pasteurized sample (90 °C, 30 sec), heated sample at 60 °C for 4,8,12 min, ultrasound sample without heating for same times with amplitudes of 24.4, 42.7, 61µm (50, 75, 100%), ultrasound sample with heating (60 °C) for same times and amplitudes. Pasteurization treatment caused a significant decrease of 31.7% in vitamin C content, 22.9% of phenolic content, 19.4% in the antioxidant content, 6.2% in anthocyanin content of the sour cherry juice. At maximum thermal ultrasound intensity and time of 12 minutes, 20.8% of vitamin C content was decreased. With increasing temperature, intensity and time of ultrasound, phenol content decreased. High intensities of ultrasound caused a significant decrease in anthocyanin content, in a way that in the intensity of 61 µm, 4 min and 60 °C, the anthocyanin content was reduced by 6.6%, respectively. In general, the results of this study indicate that increasing the intensity of ultrasound, temperature and treatment time reduced the positive effect of these treatments on qualitative properties and even reduced the bioactive compounds, that with regard to the combined results, 42.7 µm (75%) amplitude at 60 °C can be the most effective treatment in maintaining the qualitative characteristics of sour cherry juice compared to the pasteurization method