Investigation of cold plasma pasteurization on bioactive compounds, physicochemical and microbial characteristics of red grape juice

Cold plasma is a non-thermal technology and a suitable alternative to conventional thermal methods used in the food industry, which, with its antimicrobial properties, increases the shelf life of food products without negatively affecting their quality. The purpose of this research is to investigate the physicochemical, microbial and sensory properties of red grape juice pasteurized by cold plasma method (under plasma irradiation with voltage of 20, 40 and 60 kV for a period of 1, 2, 3 and 4 min and air gas) and compare it with thermal pasteurization (95°C for 5 seconds). The results showed that the effect of treatment on physicochemical properties (acidity, pH and Brix), bioactive compounds (anthocyanin, total phenol and vitamin C), color properties (components a*, b* and L*), microbial load (mold and yeast, aerobic bacteria and coliform) and sensory characteristics (taste, smell and overall acceptance) of red grape juice pasteurized by cold plasma method was significant (p≤0.05) so that with increasing amount voltage from 20 to 60 kv and time from 1 to 4 min, in grape juice pasteurized by cold plasma method, the amount of acidity, brix, color components a* and b* increased significantly (p≤0.05) and the amount pH, bioactive compounds (anthocyanin, total phenol and vitamin C), the amount of color of L* component, the amount of microbial load (mold and yeast, aerobic bacteria and coliform) decreased significantly (p≤0.05). Also, by increasing the time from 1 to 4 min, the smell score and overall acceptance decreased, and by increasing the voltage from 20 to 60 kV and the time from 1 to 4 min, the taste score decreased. Since the physicochemical, color, microbial and sensory changes of red grape juice pasteurized by cold plasma method in the conditions of 40 kv, 4 min time and air gas were less than thermal pasteurization method and more acceptable for consumption, it was introduced as a superior treatment.