Prolonged heating of honey increases its antioxidant potential but decreases its antimicrobial activity

Abstract

Background: Honey is renowned for its antioxidant, antimicrobial and medicinal properties. It is typically heated and filtered during processing to avoid crystallization. However, few studies have reported its heating effect and the antioxidant and antimicrobial activities of honey.
Materials and Methods: In this study, honey samples were collected from eight different honey-producing sites in Bangladesh and heated to 50ºC, 70ºC and 90ºC for 12 hours, while the antioxidant potentials and antimicrobial properties of the heated samples were compared with those of the unheated samples. Antimicrobial properties were investigated against one Gram-positive and eight Gram-negative bacteria. Other physicochemical and biochemical properties were also determined.
Results: Interestingly, there was a proportionate increase in the amount of antioxidant compounds (phenolics and flavonoids) as well as antioxidant potentials proportional with the amount of heat introduced, whereas the antimicrobial properties of the honey samples were reduced with increasing heat.
Conclusion: In conclusion, though prolonged heat treatment of honey can increase its antioxidant potential, antimicrobial activities are compromised.

Keywords: Honey, heat, antioxidant, antimicrobial.