Sucrose degradation during the storage of honey: impact of time, temperature, enzyme activity and botanical origin

Jointly financed by the European Union and the German federal states of Berlin, Brandenburg, Saxony-Anhalt, Saxony and Thuringia

During honey ripening in the bee colony, sucrose is degraded to fructose and glucose by the enzyme invertase. European legislation therefore limits the maximum value of sucrose in the finished honey to 5%. Nevertheless, honeys may have increased sucrose contents, although all other quality parameters indicate that the ripening process seems to have been normal and there are no signs of adulteration.

In this project, honey samples with sucrose concentrations ranging from 3.5 to 17% were examined to determine the optimum conditions for the degradation process in honey. The honeys were stored for up to 9 months at 15, 21 and 37 °C. After 9 weeks at 37 °C, the degradation process was completed with an average rate of 3.4% per week but with a 40%-drop in invertase activity.At 21 °C, the degradation rate was at 1.4% per month.At 15 °C, the process was further slowed down to 0.81% sucrose per month.The analytical results of sucrose degradation show a significant correlation with invertase activity (p < 0.01) but also with sucrose content (p < 0.001) and the pH value (p < 0.01) of the honey.

Based on these analyses, beekeepers can be given advice on how they need to store honey with a naturally elevated sucrose concentration, so that it will still meet statutory provisions while maintaining the naturalness of the honey.