Microbial Inactivation and Physicochemical Properties of Ultrasound Processed Pomegranate Juice

Abstract

The effects of ultrasound treatment at various amplitudes (50, 75, and 100%) and times (0, 6, 12, 18, 24, and 30 min) on Escherichia coli ATCC 25922 (a surrogate for E. coli O157:H7) and Saccharomyces cerevisiae ATCC 2366 levels and physicochemical characteristics (monomeric anthocyanins, color values, total phenolics, pH, and soluble solids) were determined in pomegranate juice. More than a 5-log inactivation of E. coli ATCC 25922 and a 1.36-log inactivation of S. cerevisiae ATCC 2366 were achieved after 30 min of ultrasound treatment at 100% amplitude. The log-linear and Weibull models were successfully used to estimate the microbial inactivation as a function of ultrasound treatment time (R(2) > 0.97). No significant changes were observed in total phenolics, pH, and soluble solids of the treated juice (P > 0.05). The ultrasound treatment for up to 30 min resulted in more than 92 and 89% anthocyanin retention at 75 and 100% amplitude, respectively. The redness (a*) of the juice did not change significantly after the ultrasound treatment at amplitudes of 75 and 100% for up to 24 and 12 min, respectively. No significant changes in L* and b* values were observed after ultrasound treatment at all amplitudes and after up to 30 min of treatment for 50 and 75% amplitudes. Small differences in juice color were noted based on total color difference scores.

High‐power ultrasound altered the polyphenolic content and antioxidant capacity in cloudy apple juice during storage

“…As it can be seen, ultrasound amplitude, probe diameter, and treatment time did not significantly influence the change of TP content in treated samples. Similar results were obtained by Pala, Zorba, and ÖZcan () after ultrasound treatment (500 W, 20 KHz, D = 19 mm, A = 50, 75, 100%, 35°C, treatment times: 6, 12, 18, 24, and 30 min) of pomegranate juice samples, where applied amplitude and treatment time did not significantly modified the content of TP in treated samples (Pala et al, ). In addition, ultrasound processing parameters (500 W, 19 kHz, D = 13 mm, 9–49°C, 2–10 min, A = 20, 60, and 100%) did not reveal significant changes in the content of TP for ultrasound treated melon juice samples (Fonteles et al, ).…”

“…The same results for amplitudes of ultrasound and the total phenolic content can be found in research literature. The results of Pala et al () demonstrated that different ultrasound amplitudes (50, 75, and 100%) did not have a significant effects on the increase in TP content in treated pomegranate juice (Pala et al, ). Moreover, Zafra‐Rojas et al () did not find influence of different amplitudes on the content of polyphenolic compounds for sonicated prickly pear juice (20 kHz, 1,500 W, A = 40 and 60%, 10, 15, and 25 min).…”

“…The same results for amplitudes of ultrasound and the total phenolic content can be found in research literature. The results of Pala et al (2015) demonstrated that different ultrasound amplitudes (50, 75, and 100%) did not have a significant effects on the increase in TP content in treated pomegranate juice (Pala et al, 2015). Moreover, Zafra-Rojas et al…”

“…In order to evaluate statistical influence of each ultrasound and storage parameter on the content of TP and TFL in cloudy apple juice, a multivariate statistical approach was conducted and the results are shown in the (Pala et al, 2015). In addition, ultrasound processing parameters (500 W, 19 kHz, D = 13 mm, 9-49°C, 2-10 min, A = 20, 60, and 100%) did not reveal significant changes in the content of TP for ultrasound treated melon juice samples (Fonteles et al, 2012).…”

Effects of the High Power Ultrasound on Microorganisms in Fruit Juices

“…Finally, Pala et al [7] studied the effects of ultrasound treatment at various amplitudes (50, 75, and 100%) and times (0, 6, 12, 18, 24, and 30 min) on Escherichia coli ATCC 25922 (a surrogate for E. coli O157:H7) and Saccharomyces cerevisiae ATCC 2366 in pomegranate juice. More than a 5-log inactivation of E. coli ATCC 25922 and a 1.36-log inactivation of S. cerevisiae ATCC 2366 were achieved after 30 min of ultrasound treatment at 100% amplitude.…”