Optimization of effective parameters in cold pasteurization of pomegranate juice by response surface methodology and evaluation of physicochemical characteristics

Pomegranate juice (PJ) is a well-known nutritional drink that has been widely consumed due to its health benefits. However, sedimentation of polyphenol, browning, and contamination of microorganisms are problems of fresh juice. This research aimed to evaluate the effect of ozone and ultrasound treatment on pasteurization and disinfection of PJ. The effective parameters have been optimized by response surface methodology. The optimized ozone dose was 3.5 ppm (2 L/min O-2 flow, UV power of 1.0 A) for 6 min. The amplitude level of 50% and 6 s of on/off pulse in 5 min was achieved as an optimized state for the ultrasound. Selected conditions yielded: 1760.51 mg GA/L of TPC, 72.47 mg C3G/L of TAC, 0.47 g citric acid/L of TA, 14.24 degrees Brix of TSS, 0.683 of BI for ozone gas, and 1678 mg GA/L of TPC, 72.31 mg C3G/L of TAC, 0.47 g citric acid/L of TA, 14.5 degrees Brix of TSS, 0.743 of BI for sonication. The ultrasonic and ozone treatment of PJ contaminated with Escherichia coli PTCC 1399, aerobic bacteria, and fungi resulted in 100% and 2% disinfection, respectively. The application of ultrasound as a disinfection technique has reduced microbial load with the lowest effect on physicochemical data of PJ.

Automated summary

The study assessed the effect of ozone and ultrasound treatment on pasteurization and disinfection of pomegranate juice, finding that ultrasound treatment can significantly reduce microbial load with minimal impact on the physicochemical properties of the juice.