Diastase and Invertase Activity Changes and 5-Hydroxymethyl-2-Furfural Formation in Honeys Under Influence of Microwave Irradiation

摘要

Three types of honey including lime (Tilia spp.), buckwheat (Fagopyrum spp.) and acacia (Robinia pseudoacacia) honeys were analyzed. Honeys were subjected to conventional heating at a temperature of 60 degrees C and heated in a microwave field. Depending on the type of honey, the temperature obtained in the microwaves was in the range of 48 and 69 degrees C. After processing, honeys were stored for 3months in uniform condition (ambient temperature, darkness, constant humidity) and subsequently reanalyzed. Oversized decrease in the value of diastase number was found in only two cases of honeys exposed to microwave field (after storage). Under the experiment conditions, there was no clear changes in the HMF concentration The largest increase was found in the case of acacia (A-CD) and buckwheat (B-B) honeys. For these types of honeys, increase in HMF concentration was of 2mg/kg and 3mg/kg, respectively. The biggest impact of the microwave irradiation was observed on the invertase activity. All the tested honeys, especially those subjected to microwave irradiation, showed a statistically significant decrease (five times the initial value) in the activity of this enzyme. Decrease in the diastase activity in microwaved honeys was from 6.8 to 3.7 degrees Schade in case of acacia honey (A-B) from 27.0 to 11.6 degrees Schade in case of buckwheat (B-OSP) honey.