Effects of high-pressure and high-shear homogenization pretreatments on the microbiological, psychochemical properties and powder properties of freeze-dried kefir powder

Year 2025, Volume: 6 Issue: 2, 53 - 62, 30.12.2025

Latife Betül Gül , Osman Gül

https://doi.org/10.55147/efse.1825450

Abstract

Recently, the use of emerging processing technologies has gained importance to improve various properties of milk and milk products. In particular, studies on improving the quality properties of powders, such as powder flow properties, wettability, and solubility, have gained momentum. In this study, the effect of high-pressure homogenization (HPH) at different pressures (50 and 100 MPa) and high-shear homogenization (HSH) at different shears (2500 and 5000 rpm) on the microbiological, physicochemical properties, and powder flow behavior of kefir powder, before drying, was determined. The higher pressure and shear employed resulted in the highest loss of viability and the lowest average particle size of kefir. After drying, the highest number of viable cells (lactobacilli, lactococci, and total bacteria) was present at levels of 9.43, 9.37, and 9.81 log cfu/g, respectively, in the kefir powder sample subjected to 100 MPa pressure. The applied homogenization pretreatments resulted in a partial increase in the L* value and solubility of kefir powder, while also leading to a significant improvement in wettability. Depending on the applied homogenization process, the decrease in particle size increased both bulk and tapped densities. Additionally, the angle of repose (AOR) value of kefir powders decreased from 37.48° to 29.44°, depending on the applied homogenization pretreatment, indicating that homogenization pretreatment significantly improved the powder flow properties. It was concluded that homogenization pretreatment of kefir could improve the microbiological and powder properties of kefir powders.

Keywords

kefir , kefir powder , high-pressure homogenization , high-shear homogenizaton , powder properties

Ethical Statement

This study did not involve human participants or animal experiments. All procedures related to the collection and handling of kefir samples and microbial analyses were conducted in accordance with institutional guidelines and standard laboratory safety practices. Therefore, ethical approval was not required for this research.

Supporting Institution

This research was carried out using the laboratory facilities of Kastamonu University. No external funding was received for this study.

Thanks

The authors would like to thank Kastamonu University for providing the laboratory facilities necessary to carry out this research. The authors also acknowledge the support and assistance of the laboratory staff during the experimental studies.

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