Hydroxymethylfurfural content, diastase activity and colour of multifloral honeys in relation to origin and storage time

Abstract

The aim of the study was to compare the quality of multifloral honeys in relation to origin (domestic vs. foreign), and storage time (before vs. after the date of minimum durability) available on the Polish retail market. The study was conducted on 24 samples of multifloral honey, including domestic ones (i.e. originated directly from beekeepers in open-air markets, or purchased in a retail chain), and foreign (i.e. from inside or outside the EU) bought in hypermarkets. In addition, the study comprised 5 samples of honey after the date of minimum durability. The content of hydroxymethylfurfural (5-HMF), diastase number (DN) and colour according to CIE L*a*b* were determined in honeys. In the fresh multifloral honeys (irrespective of origin) the content of 5-HMF ranged from 1.17 to 18.54 mg·kg-1, and DN ranged from 8.36 to 34.88. Thus all samples met the legal requirements (5-HMF<40 mg·kg-1 and DN<8 on the Schade scale). Significant (P≤0.01) deterioration in the quality of the honey was noted after the date of minimum durability. The mean HMF content (93.87 mg·kg-1) was twice as high as the acceptable value, and the mean DN (6.45) was lower than the accepted limit. Significant differences (P≤0.01) were noted between mean values for all colour coordinates considering the date of minimum durability. The colour of the honey after the date of minimum durability was significantly darker and had lower saturation (L*=43.18 and C*=21.23) than the fresh honey (L*=62.11 and C*=32.66).