Cell by cell pilot study of ultrasonic velocity in honey: from immature sugar solution to cell capping

With a specific ultrasonic device adapted to small volumes analysis, we carried out a pilot study of cell by cell honey ultrasonic velocity in a beehive. In this context, we followed, cell by cell, the evolution of ultrasonic velocity in honey throughout its elaboration, from fresh liquid just deposited into cells, to the capping. The results, averaged over the whole honeycomb correlated rather well with moisture content (in the range 14-64%) even if, for the same moisture content, the values of velocities significantly varied suggesting differences in sugar composition. Concerning cell by cell analysis, data collected showed that ultrasonic velocity significantly differs from one cell to another, versus time and versus location in the honeycomb. These first results demonstrate that ultrasonic velocity measured cell by cell could be precious data if it would be correlated to other physicochemical parameters such as water activity. Our ultrasonic method is not, in its present form, directly applicable for real time non-destructive monitoring of the hive. Nevertheless, our first results prove that ultrasonic methods could be interesting for honey evaluation during the ripening process at the cell level, using volumes inferior to the millilitre and not in a macroscopic way.