Related Experiment Video
Updated: May 18, 2026
Live/Dead Staining for Quantifying Viable but Not Culturable Cells in Manuka Honey-Treated Wound-Causing Bacteria
Published on: April 25, 2025
Effect of high hydrostatic pressure on antimicrobial activity and quality of Manuka honey
Nasser A Al-Habsi1, Keshavan Niranjan
1Department of Food and Nutritional Sciences, University of Reading, Whiteknights P.O. Box 226, Reading RG6 6AP, UK. nhabsi@hotmail.com
Abstract:
The antimicrobial activity of Manuka honey is of major interest to beekeepers and the honey industry. In this study, the effect of high hydrostatic pressure and thermal treatments on antimicrobial activity and quality parameters (principally, diastase number and hydroxymethylfurfural levels (HMF)) of Manuka honey were investigated. The honey was subjected to different pressures (100-800MPa) at 25°C for a range of holding times (15-120min). The antimicrobial activity was found to increase with applied pressure for a given holding time, while the diastase number and HMF levels remained, more or less, unaffected. The percentage inhibition in microbial growth correlated linearly (R(2)=0.94) with methyglyoxal concentration in the honey after treatment over the entire range of pressure, temperature and holding times studied. Maximum percentage inhibition (78.83%) was achieved when honey was subjected to 800MPa compared to the control (57.93%). Thermal treatments at higher temperatures were found to have a detrimental effect on antimicrobial activity based on percentage inhibition as well as methylglyoxal content. Thus, it can be concluded that the levels of methylglyoxal, and therefore the antimicrobial effect of Manuka honey, can be enhanced by using high pressure processing without adversely affecting honey quality.
Insights
High hydrostatic pressure processing enhances Manuka honey's antimicrobial activity by increasing methylglyoxal. This method improves potency without negatively impacting key quality indicators like diastase number and hydroxymethylfurfural (HMF).
Area of Science:
- Food Science
- Biotechnology
- Analytical Chemistry
Background:
- Manuka honey's antimicrobial properties are valuable to the honey industry.
- Investigating processing effects on honey quality and bioactivity is crucial.
Purpose of the Study:
- To determine how high hydrostatic pressure (HHP) and thermal treatments affect Manuka honey's antimicrobial activity.
- To assess the impact of these treatments on quality parameters such as diastase number and hydroxymethylfurfural (HMF).
Main Methods:
- Manuka honey samples were treated with high hydrostatic pressure (100-800MPa) at 25°C for varying durations (15-120min).
- Thermal treatments were also applied.
- Antimicrobial activity, methylglyoxal concentration, diastase number, and HMF levels were measured.
Main Results:
- Antimicrobial activity increased with applied pressure.
- Diastase number and HMF levels remained largely unaffected by HHP.
- A linear correlation (R²=0.94) was observed between microbial growth inhibition and methylglyoxal concentration.
- Maximum inhibition (78.83%) was achieved at 800MPa, compared to the control (57.93%).
- Thermal treatments negatively impacted antimicrobial activity and methylglyoxal content.
Conclusions:
- High hydrostatic pressure processing can enhance Manuka honey's antimicrobial effect by increasing methylglyoxal levels.
- HHP is a viable method for boosting Manuka honey's bioactivity without compromising its quality.
- Thermal processing is less suitable for preserving or enhancing antimicrobial properties.
More Related Videos
Related Concept Videos
01:28Antimicrobial Effectiveness
01:25Clinical Significance of Antibiotic Resistance
01:18Surface Membrane Barriers
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...