Effects of storage temperature on HMF and diastase activity of strained honeys

Abstract

This research intends to reveal the effects of different storage temperatures on the HMF amounts and diastase activities of strained flower honey and honeydew honey samples produced by different companies in Turkey. In this context, the initial HMF values and diastase activities of the strained flower honey and honeydew honey samples belonging to five different companies, collected at the date of filling, were examined with defined quality criteria (moisture, sugar, pH, acidity, electrical conductivity and ash). Samples were stored at certain temperatures (10±2 °C, 22±2 °C, 35±2 °C), and were analyzed at the end of each of the three-month periods (3rd, 6th, 9th and 12th months) regarding HMF and diastase activity. According to the results, average HMF values of the flower honey and honeydew honey samples stored at 10±2 °C and 22±2 °C for one year did not exceed 40 mg/kg, which is given as the limit HMF value in the Turkish Food Codex (TFC) Directive on honey, while it rapidly increased in the samples stored at 35±2 °C, and was determined to be over 40 mg/kg as of 6th month onwards. In addition, average diastase activities of the samples at 10±2 °C and 22±2 °C did not drop below the limit value of 8 in TFC, though it was determined to be below 8 as of 6th month onwards, for the flower honey stored at 35±2 °C. To conclude, decrease in diastase activity shortens the shelf lives set by the firms. By providing proper production and storage conditions, all quality criteria should be ensured to remain consistent with the TFC Directive on honey.