The Effect of the Use of Essential Oils in the Feed of Bee Families on Honey Chemical Composition and Antimicrobial Activity

Abstract

Honey is a natural food with pharmacological properties. The present study was focused on the use of essential oils in the supplementary feeding of bee families for three weeks (spring). The purpose was to monitor the effect of essential oils (basil, thyme, juniper, cloves, mint, cinnamon, oregano, rosemary) on the chemical components of the resulting honey. The honey sampling period was carried out before the administration of essential oils in the supplementary feed of the bee families, after the administration of essential oils in the bee feed, respectively, after the first harvest (rapeseed). The honey samples were subjected to chemical analysis to determine humidity, impurities, ash, pH, acidity, total phenolic content (TPC) and flavonoid content (FC), reducing sugar content and antioxidant activity. In addition, the antimicrobial activity against nine strains was tested. We found out that all the essential oils used had a positive effect on the chemical composition of honey, especially the essential oil of oregano, mint, thyme, cinnamon. Experimental variants in which juniper and clove essential oil were introduced reduced the acidity of honey by 28.12% and 35.48%, respectively. Ash content varies between 0.23% and 0.46%, impurities content between 4.11% and 9.11%, while the values for pH were between 3.42 and 4.03. As for the TPC, they have increased considerably in all experimental variants to which essential oil has been added, compared to the batch fed only with sugar syrup, the highest value being recorded for the sample treated with cinnamon after the third harvest (163.94 mg/100 g). The FC values vary between 8.41–44.36 mg/100 g, depending of the treatment applied and the period of harvesting. Regarding the antimicrobial activity, the results highlighted that the essential oils present in the diet of bees produced honey with antimicrobial effect increased after two weeks after administration.