The Effect of Temperature Variations on the 5-Hydroxymethylfurfural Content, Antioxidant and Antimicrobial Properties of Honey.

Apis dorsata honey is a rich source of natural antioxidants and antibacterial compounds. Thermal processing is commonly used to improve honey fluidity and delay crystallization; however, it may also affect bioactive properties and promote the formation of 5-hydroxymethylfurfural (5-HMF). We evaluated the impact of temperature regimes on biological activities and 5-HMF contents of A. dorsata honey. Honey samples were collected from A. dorsata colonies. Honey color, total phenolic content (TPC), total flavonoid content (TFC), 5-HMF content, and antibacterial activity against Escherichia coli and Staphylococcus aureus were investigated after being treated at room temperature, 55 °C, 65 °C, 75 °C, and 85 °C for 0.5, 1, and 2 h. Heating at 55 °C, 65 °C, 75 °C, and 85 °C significantly enhanced color intensity, TPC, and TFC. Samples treated at 85 °C for two hours showed the highest antioxidant activity, with an EC50 significantly lower than that of the others (51.31 ± 0.77 mg/mL). Conversely, 5-HMF content increased markedly with increasing exposure temperature and time. Antibacterial assays revealed that all treated samples inhibited E. coli, whereas no inhibitory activity was detected against S. aureus. These results define important processing parameters in food safety for heating honey to preserve bioactivity integrity without loss in quality and maintenance of product stability and sustainability.