Invertase activity in honey

The invertase activity was determined for 499 honeys (27 multifloral and 472 unifloral from Arbutus, Carduus, Castanea, Citrus, Erica, Eucalyptus, Hedysarum, Helianthus, Rhododendron, Robinia, Rosmarinus, Taraxacum, Thymus, Tilia, fir honeydew and honeydew produced by Metcalfa pruinosa), in order to determine its variability and establish the range characteristic for each honey type. The results show that invertase activity varies considerably in the different honey types (from less than 0.5 to more than 30 IN). Robinia Arbutus, Citrus, Erica and Rosmarinus have the lowest values (usually less than 10) and the two honeydew honeys the highest (more than 18). The diastase content of the samples was also measured, to compare the content of the two enzymes, and a certain correlation was observed (r = 0.835, P < 0.001). The IN/DN ratio ranges from less than 0.1 to more than 2. The possible role of invertase and IN/DN ratio in honey quality evaluation is discussed. (C) Inra/DIB/AGIB/Elsevier, Paris.