Physicochemical and Antioxidant Properties of Honey: Effect of Heat and Storage

Seven commercially processed and two unprocessed honey samples of different origins were evaluated for their physicochemical, biochemical and anti-oxidant properties. The initial values of the different parameters varied significantly (p < 0.05) and ranged as follows: pH, 3.65 - 4.16; colour intensity, 103 - 1029 mAU; HMF, 1.00 - 58.85 mg/kg; proline, 34.51 - 520.11 mg/kg; phenolic, 32.48 - 86.73 mg GAE/100g; flavonoid, 2.27 - 9.73 mg QE/100g; IC₅₀, 90.00 - 198.95 mg/mL. Except proline, the different parameters tested were found to conform to the values set by the Codex Alimentarius Commission (2002). The impact of thermal treatment was also investigated on the physicochemical and biochemical parameters. The results showed a tremendous increase in the HMF in samples originated from Mauritius (4) and India (8) as the temperature was increased which may be an indication of adulteration while the proline content showed a decrease for all the samples compared to their initial values. Anti-oxidant properties of the honey samples were found to increase and showed strong correlation with the phenolics, flavonoids and colour intensity. No significant variation was observed in the different parameters of the honey samples stored for 3 months after opening except for HMF value for sample 4.