Antimicrobial and antioxidant properties of Saturn peach subjected to ultrasound-assisted osmotic dehydration

This study was performed to investigate the effectiveness of ultrasound-assisted osmotic dehydration on reducing foodborne pathogens (Escherichia coli, Enterococcus faecalis, Salmonella Typhi and Shigella sonnei), as well as its impact on moisture content and antioxidant properties of Saturn peach. Peach samples were inoculated and underwent ultrasonic waves (50 and 75% amplitudes). Afterwards, the osmotic dehydration was performed by immersing the samples in 70% sucrose solution (for 4, 8 and 12 h). Results indicated that ultrasound pre-treatment markedly diminished the microbial count and the reduction levels of pathogens enhanced with the increase of ultrasound amplitude. The greatest reduction in pathogens was observed at 75% amplitude after 12 h storage in osmotic solution, in which the mean number of E. coli, E. faecalis, S. Typhi and S. sonnei was reduced to 0.1, 4.2, 3.7 and 0.1 log CFU/g, respectively. Additionally, osmotic dehydration treatment significantly reduced the amount of moisture content, total phenolics and DPPH antiradical activity of samples. It should be added that increasing the ultrasound amplitude led to a further decrease in the mentioned parameters.