Changes in the Chemical Composition and Antimicrobial Activity of Linden, Buckwheat and Sunflower Honey Stored at Low Temperatures

Abstract

Natural bee honey can change its physicochemical and biological properties during storage. Literature data on long-term storage of honey at low temperatures (from 0 to -20 °C) indicate that this ensures the stability of some physicochemical parameters. Despite the potential benefits of these temperature regimes for practical use, it is important to consider their potential negative effects on honey quality. The aim of this study was to investigate the influence of various temperature conditions on the physicochemical and biochemical parameters of linden, buckwheat, and sunflower honeys during storage for 12 months. For the first time, a wide range of physicochemical parameters of honey samples was analyzed before and during storage for 12 months at temperatures of 18, 10, 5, 0, -5, -10 and -18 (±2) °C. The evaluation of the physicochemical parameters before storage demonstrated that the samples fully complied with the Interstate Standards. Throughout the storage period, the HMF level remained stable at -18 °C, whereas it significantly increased at higher temperatures; for example, after 12 months at 18 °C, the increase ranged from 472.5% to 488.1%, depending on the botanical origin of the honey. However, maximum permissible concentration – MPC (25 mg/kg) was not exceeded. A decrease in the activity of diastase, D-glucose-1-oxidase and catalase was observed at all temperature conditions already during the first month of storage. Minimal changes were observed at 0 and 5 °C. Hydrogen peroxide (H2O2) remained stable in this temperature range. Moisture content, total mass fraction of reducing sugars, and acidity did not change significantly in all samples. An antimicrobial study using test cultures found that honey stored at 5 and 0 °C had the greatest inhibitory effect. The data obtained demonstrates that the optimal temperature range for 12-month storage of honey is between 5 and 0 °C. These findings can be used as supplementary guidance when making amendments to regulatory documents governing storage requirements for this product.