Effects of high hydrostatic pressure on antimicrobial protein stability and the rheological and shelf-life properties of donkey milk

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Köker A., Budak Ş., Alpas H.

The Journal of dairy research, vol.90, no.3, pp.292-298, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 90 Issue: 3
  • Publication Date: 2023
  • Doi Number: 10.1017/s0022029923000572
  • Journal Name: The Journal of dairy research
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Periodicals Index Online, Agricultural & Environmental Science Database, Analytical Abstracts, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Food Science & Technology Abstracts, Veterinary Science Database
  • Page Numbers: pp.292-298
  • Keywords: Donkey milk, high hydrostatic pressure (HHP), lactoferrin, lysozyme, shelf-life
  • Middle East Technical University Affiliated: Yes


The effects of high hydrostatic pressure (HHP) and heat treatments on antimicrobial protein stability and on the physico-chemical, microbiological, rheological and shelf-life properties of donkey milk were investigated. Although heat treatment at 75°C for 2 min resulted in 1.50 log CFU ml-1 microbial inactivation, losses in activities of lysozyme (58%) and lactoferrin (82%) were observed due to whey protein denaturation. By contrast, HHP application at 400 MPa caused lower enzyme activity losses (22 and 37% respectively) whilst maintaining a significant reduction of microbial load (1.80 log CFU ml-1). Color analyses showed that the lightness values of all samples decreased during storage. Higher flow consistency (viscosity) and lower flow behavior indexes were observed in heat-treated samples compared to untreated and HHP-treated ones, which can be explained by advanced protein denaturation during heat-treatment. The results suggest that HHP is a more suitable process than heat treatment for preservation of donkey milk within the conditions studied.