The Effect of UV-C Radiation Compare to Pasteurization on the Qualitative and Microbial Properties in Red Grape Juice

This study has investigated the effect of UV-C radiation at doses of 8, 15 and 30 W compare to pasteurization (LTLT) on turbidity and total phenol content changes of red grape juice immediately after processing, and some chemical (pH, acidity, ascorbic acid, anthocyanins, antioxidant capacity, and color), and microbial (mold and yeast) properties during the period of 0, 30, 60, 90 and 120 days of storage at room temperature. Eleven treatments were given, including UV-C treatments at 2, 6, and 10 minutes, as well as dosages of 8, 15, and 30 watts, with a control and a pasteurized grape juice sample. The results showed that overtime in during storage, the Brix values decreased, and also the irradiated samples at a dose of 30 W for 2 and 6 min showed the lowest Brix values. When compared to shorter irradiation intervals, irradiating grape juice for 10 minutes reduced acidity and increased pH. Irradiated grape juice had higher ascorbic acid, anthocyanin, total phenol, and antioxidant activity compared to pasteurized samples. Irradiated samples showed higher antioxidant activity at the end of the storage period compared to other treatments. UV-C radiation compare to pasteurization was able to prevent the turbidity and color changes in red grape juice. In terms of quality and microbiological features, 30 watt treatments for 6 and 10 minutes were favored above other treatments. Overall, UV-C radiation as a suitable alternative to the usual pasteurization led to better preservation of the qualitative and microbial properties of red grape juice.