The influence of storage conditions and heating on diastase, invertase activity and hydroxymethylfurfural in Iraqi honey

Abstract

The purpose of this research was to evaluate the effect of heating treatments and storage on diastase number, invertase activity and hydroxymethylfurfural (HMF) in several types of Iraqi honey (represented in most of Iraq's governorates). Average values for the quality characteristics of fresh honey ranged between (8-21) units of diastase number, 107.5-284.3 U/kg invertase activity and 7.6-40.3 mg/kg HMF. The honey samples were subjected to heating at 50, 65, 75 Cº for 30 minutes. Then the honey samples were left at room temperature 25-30 °C and stored for 6 months for evaluation. Changes in diastase number, invertase activity and HMF content were observed in 3 and 6 month of storage. The values of these indicators decreased from the basic values and ranged between (1.1-3.6 units), (26.8- 70.8 U/kg) and (21.3-112.8 mg/kg) respectively after being subjected to heating at a temperature of 75°C for 30 minutes after being stored for 6 months.