PASTEURIZATION OF HONEY USING 915 MHZ MICROWAVE HEATING: EFFECTS ON HYDROXYMETHYLFURFURAL (HMF), CRYSTALLIZATION, PHYSICOCHEMICAL PROPERTIES, AND MICROBIAL SAFETY

Pasteurizing honey is essential for delaying crystallization, improving safety, and extending shelf life, but traditional methods raise concerns over energy efficiency and quality changes. Microwave (MW) heating at 915 MHz offers efficient, volumetric heating, preserving flavor and nutrients while reducing energy usage. Its precise control ensures safety in shorter timeframes, making it a promising alternative for honey pasteurization. This study evaluated the effectiveness of 915 MHz MW heating for honey pasteurization, focusing on hydroxymethylfurfural (HMF), crystallization, physicochemical properties, microbial safety, and consumer perception and acceptance. Honey samples were processed at power levels of 15, 16, and 18 kW with a flow rate of 1.62 gal/min, resulting in specific energy fluxes of 4.35, 4.87, and 5.97 J/kg·s⁻¹. Increased specific energy fluxes had no statistically significant effect on the HMF and microbial loads. The MW treatment effectively controlled HMF content within acceptable limits. As specific energy fluxes increased to 5.97 J/kg. s^-1 HMF Content increased from 18.88 ± 0.05 mg/kg to 20.31± 1.46 mg/kg, a fructose/glucose ratio of 1.17 at 4.87 J/kg·s⁻¹ indicating potential delay in crystallization. There was a significant increase in total phenolic content from 214 ± 5.01 mg of gallic acid/kg to 569 ± 35.91 mg of gallic acid/kg. The study also showed significant changes in moisture content, water activity, color, pH, viscosity, and total sugar content. A sensory evaluation with 69 participants showed no significant differences in aroma, flavor, and overall liking compared to commercial honey. These findings emphasize the potential of MW heating as a viable alternative for honey pasteurization.