1- M. Sc. Graduated of the Department of Food Science and Technology, Fasa Branch, Islamic Azad University, Fasa, Iran
2- Assistant professor of the Department of Food Science and Technology, Faculty of Agriculture, Fasa Branch, Islamic Azad University, Fasa, Iran , d.jafarpour84@yahoo.com
Abstract: (95 Views)
Osmotic dehydration is the process of extracting water based on placing food in a hypertonic solution. The current study was performed to investigate the effectiveness of ultrasound-assisted osmotic dehydration (UAOD) on reducing foodborne pathogens (Escherichia coli, Enterococcus faecalis, Salmonella Typhi and Shigella sonnei) on apple slices. Moreover, the effects of UAOD treatment on moisture content, amount of total soluble phenolics and DPPH radical scavenging activity in treated apples were measured. Yellow apple slices were inoculated with each pathogen separately and underwent ultrasonic waves at two levels of amplitudes (40 and 70 %) for 20 min. Afterwards, the osmotic dehydration process was performed by immersing the samples in 70% sucrose solution for a contact period of 4, 8 and 12 h. Results indicated that US pre-treatment alone markedly diminished the microbial count and the reduction levels of four pathogenic bacteria enhanced with the increase of US amplitude. Furthermore, the results showed that the degree of reduction of pathogens depended on the duration of the osmotic dehydration process and the amplitude of sonication treatment. The greatest reduction in pathogens was observed at 70% amplitude after 12 h storage in an osmotic solution, in which the mean number of E. coli, E. faecalis, S. Typhi and S. sonnei was reduced to 0.1, 4.0, 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, and this reduction was greater in sonicated samples as compared to the control sample. It should be added that increasing the ultrasound amplitude led to a further decrease in the mentioned parameters. Therefore, this non-thermal combination processing can be used to increase the overall safety and quality of apple fruit.
Received: 2025/06/23 | Accepted: 2025/07/23 | Published: 2025/07/23