Impact of ultrasound treatment on viability of Staphylococcus aureus and the human milk antioxidant activity

Microbial decontamination assisted by ultrasound-based processing technologies in food and model systems: A review

Ultrasound (US) technology is recognized as one of the emerging technologies that arise from the current trends for improving nutritional and organoleptic properties while providing food safety. However, when applying the US alone, higher power and longer treatment times than conventional thermal treatments are needed to achieve a comparable level of microbial inactivation. This results in risks, damaging food products' composition, structure, or sensory properties, and can lead to higher processing costs. Therefore, the US has often been investigated in combination with other approaches, like heating at mild temperatures and/or treatments at elevated pressure, use of antimicrobial substances, or other emerging technologies (e.g., high-pressure processing, pulsed electric fields, nonthermal plasma, or microwaves). A combination of US with different approaches has been reported to be less energy and time consuming. This manuscript aims to provide a broad review of the microbial inactivation efficacy of US technology in different food matrices and model systems. In particular, emphasis is given to the US in combination with the two most industrially viable physical processes, that is, heating at mild temperatures and/or treatments at elevated pressure, resulting in techniques known as thermosonication, manosonication, and manothermosonication. The available literature is reviewed, and critically discussed, and potential research gaps are identified. Additionally, discussions on the US's inactivation mechanisms and lethal effects are included. Finally, mathematical modeling approaches of microbial inactivation kinetics due to US-based processing technologies are also outlined. Overall, this review focuses only on the uses of the US and its combinations with other processes relevant to microbial food decontamination.

A comparative study on the effects of boiling and ultrasonication on radical scavenging activity, casein particle size, and whiteness of milk

Background and Aim

Different processing treatments affect the functional properties of milk. This study aimed to evaluate the effects of boiling and ultrasonication on radical scavenging activity, micellar casein particle size, and the whiteness of milk.

Materials and Methods

Milk was subjected to boiling and ultrasonication treatments. Then, the micellar casein size and the whiteness of the milk were evaluated using L-Value- intensity of whiteness and the radical scavenging capacity of the milk was evaluated using 1,1-diphenyl-2-picrylhydrazyl method.

Results

The radical scavenging activity of the milk was found to be reduced during the different processing treatments, but this decrease was non-significant for the ultrasonication treatment (p>0.05). However, a significant reduction in radical scavenging activity (p<0.05) was observed for the boiled milk. Micellar casein size reduction was observed after both treatments, and boiling had a significant effect (p<0.05) on the micellar casein particle size. We found that the whiteness of skim milk was significantly decreased after boiling treatment, but was not significantly decreased after ultrasonication. Ultrasonication had a non-significant effect on the whiteness of ultrasonicated milk which was observed.

Conclusion

Ultrasonicated milk had a very non-significant effect on the antioxidant activity (radical scavenging activity) of milk, whereas the effect of boiling was significant. Ultrasonication treatment increases the shelf-life of milk while retaining its bioactive properties.