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.

The increase in the number of microorganism strains with resistance to anti-bacterial and disinfecting agents is getting more and more prevalent and has become an issue when treating the human and animals diseases and carrying out measures for disinfection treatment. This problem can be solved by using photodynamic and light-independent therapy. In both areas, metalloporphyrins have been successfully used for many years. One of the most famous representatives of porphyrins is chlorophyll (Chl). This work aims to develop of Chl polymeric form by incorporation in poly(lactic acid) (PLA) and study its inhibitory effect against Staphylococcus aureus and Escherichia coli, which are known as contaminants of the mucous and skin epithelium of humans and animals. The preparation method of Chl polymeric form is presented. The degree of Chl incorporation into PLA was more than 98%. The assessment of antimicrobial activity was carried out by measuring the inhibition zone diameters after bacterial incubation for 24–96 h. It was shown that Chl and Chl-PLA at a dosage of 75 µg inhibited S. aureus significantly. The exclusively bacteriostatic effect on E. coli was observed. These results can be used in the development of dosage forms and disinfectants.

В результате анализа образцов натурального пчелиного, термообработанного и искусственного меда была установлена обратная корреляция между токсическим соединением 5-гидроксиметилфурфуролом и пероксидом водорода, детектируемыми хроматографическим и спектрально-иодометрическим методами, соответственно. Показано, что повышение температуры обработки натурального меда приводит к снижению концентрации пероксида водорода и повышению уровня 5-ГМФ. Однако, во всех термообработанных образцах 5-ГМФ не превышал допустимый нормативной документацией предел - 25,0 мг/кг, даже при воздействии 80°С (16,1±0,6 мг/кг). В образцах искусственного меда наблюдалось незначительное содержание пероксида водорода (~0,000003 моль/л) и завышенная концентрация 5-ГМФ (118,8±4,1 мг/кг). Несмотря на то, что корреляционная зависимость между содержанием 5-ГМФ и пероксидом водорода не была линейной, снижение концентрации пероксида водорода свидетельствовало как о запрещенном термическом воздействии на мед, так и о факте фальсификации этого продукта. As result of the analysis of the natural bee, heat-treated and artificial honey samples, the inverse correlation was established between the toxic compound 5-hydroxymethylfurfural and hydrogen peroxide, detected by HPLC and spectral iodometric methods, respectively. It has been shown that the increase in natural honey processing temperature leads to the decrease in the concentration of hydrogen peroxide and the increase of 5-HMF. However, 5-HMF didn’t exceed the limit allowed by the regulatory documentation - 25.0 mg/kg, even when exposed to 80°C (16.1±0.6 mg/kg), in all heat-treated samples. The insignificant content of hydrogen peroxide (~0.000003 mol/L) and the overestimated concentration of 5-HMF (118.8±4.1 mg/kg) were observed in the artificial honey samples. Despite the fact that the correlation between the content of 5-HMF and hydrogen peroxide wasn’t linear, the decrease in the concentration of hydrogen peroxide indicated both the forbidden temperature effect on the honey and the falsification of this product.

This work is devoted to the electrospinning of biocompatible fibrous matrixes for microbial wound therapy. The problem of treating staphylococcal-infected wounds remains urgent. In this study, we propose a new approach to the use of the chlorophyll (Chl) and poly-3-hydroxybutyrate (PHB) composite system in the treatment of infected wounds. The structure and properties of the electrospun polymer matrix based on PHB modified with various concentrations of Chl was investigated by SEM, confocal microscopy, DSC, EPR. The release rate, fluorescence, and antimicrobial activity of Chl incorporated into PHB were studied. The high efficiency of the developed materials was shown with the participation of laboratory animals.

Натуральный пчелиный мед – ценный пищевой продукт, пользующийся большой популярностью во многих странах мира. Однако, высокий спрос на него привел к учащению случаев фальсификаций. В России наиболее распространенными и сложными для выявления представляются два фальсификата – «искусственный мед» и «сахарный мед». В соответствии с требованиями нормативной документации (НД) их определение основывается на физико-химическом анализе, что, к сожалению, не всегда дает возможность получить достоверные результаты. Согласно литературным данным, о качестве меда позволяют также судить такие показатели, как уровень активности каталазы и D-глюкозо-1-оксидазы, а также концентрация пероксида водорода (H2O2). В статье приведены данные по определению возможности выявления указанных фальсификатов на основе оценки физико-химических показателей, рекомендованных НД, и дополнительных критериев, с целью повышения объективности получаемых результатов. Полученные данные сравнивались как с критериями НД, так и с физико-химическими показателями задействованных в экспериментах образцов натурального гречишного меда. Было установлено, что фальсификат «искусственный мед» не соответствовал требованиям НД по всем параметрам кроме содержания влаги. Также, была детектирована низкая ферментативная активность и концентрация H2O2 (в 74 раза меньше, чем в натуральном меде). Другой фальсификат – «сахарный мед», в целом, по всем критериям соответствовал НД, поэтому его выявление было более сложным. Активность ферментов хотя и была снижена, но не столь значительно. К наиболее показательным параметрам можно было отнести только низкую концентрацию H2O2 (в 7,1 раза меньше, чем в натуральном меде). Кроме того, недостаточное содержание H2O2 в фальсификатах обуславливало существенное снижение их антибактериальной активности в отношении Escherichia coli (штамм 1257) и Staphylococcus aureus (штамм 209-P). Таким образом, концентрация H2O2 – важный показатель натуральности меда, его использование может быть целесообразным при подозрении на фальсификацию в качестве дополнительного критерия. Natural bee honey is a valuable food product, which is very popular in many countries around the world. However, the high demand for it has led to the increase in adulteration cases. In Russia, two adulterations seem to be the most common and difficult to detect – “artificial honey” and “sugar honey”. In accordance with the requirements of State Standards, their detection is based on physicochemical analysis, which, unfortunately, doesn’t always make it possible to obtain reliable results. According to the literature data, the quality of honey can also be evaluated by such indicators as catalase and D-glucose-1-oxidaseactivity, as well as the concentration of hydrogen peroxide (H2O2). The article presents data on determining the possibility of identifying these adulterations based on the evaluation of physicochemical parameters recommended by State Standards, and additional criteria, in order to increase the objectivity of the obtained results. The obtained data were compared both with State Standards criteria and with physicochemical parameters of natural buckwheat honey samples involved in this experiment. It was found that "artificial honey" didn’t meet the requirements of State Standards in all parameters except for moisture content. Also, low enzymatic activity and concentration of H2O2(74 times less than in natural honey) was detected. Another adulteration "sugar honey" according to all criteria met State Standards, so its identification was more difficult. The enzyme activity was slightly reduced. Only a low H2O2 concentration could be attributed to the manifesting indicators (7.1 times less than in natural honey). Thus, the obtained data made it possible to conclude that it is expedient to use the measurement of H2O2 concentration as the additional parameter in case of suspected honey adulterations. In addition, the insufficient H2O2 content in honey adulterations caused the significant decrease in their antibacterial activity against Escherichia coli(strain 1257) and Staphylococcus aureus(strain 209-P). Thus, the H2O2concentration is the important indicator of honey naturalness, its use may be appropriate as the additional criterion in case of falsification suspicion.

The chemical composition and antibacterial activity of heather honey (Calluna vulgaris) subjected to heat treatment at 35–40°C for 12 h are studied. The temperature range (38–40°C) at which the H₂O₂ concentration and D-glucose-1-oxidase activity decrease and the 5-hydroxymethylfurfural content increases is identified. The degree of chemical changes is directly proportional to the temperature and time of thermal exposure. The correlation between changes in the chemical composition and antibacterial activity of honey against the Escherichia coli (strain 1257), Staphylococcus aureus (strain 209-P), and Bacillus cereus (strain 96) test microorganisms is established. The obtained results show that heating the honey to 37°C even for 12 h does not cause undesirable changes in its chemical composition or decrease in antibacterial activity. Thus, this temperature regime can be considered gentler and recommended for use in the heat treatment of this food product.