Makarewicz M., Kowalski S., Lukasiewicz M., Małysa-Paśko M. (2017): Antimicrobial and antioxidant properties of some commercial honeys available on the Polish market. Czech J. Food Sci., 35: 401-406.Six commercial natural honeys available on the Polish market were characterised with respect to their geographical and floral origins, physicochemical parameters and microbial properties. The study focused on a determination of the activity of the main enzymes, antioxidant capacity and identification of antimicrobial effects. Fructose was the predominant sugar in all tested honeys. The largest amount of hydroxymethylfurfural (HMF) was found in eucalyptus honey. It was found that thyme honey was characterised by the highest values of diastase number, invertase activity, antioxidant capacity and total phenolic content. A very week correlation between the antioxidant properties of tested honeys and their antimicrobial action against tested bacteria was observed. M. luteus and P. putida were resistant to most honey samples. All tested honeys showed antibacterial activity against e. coli and P. myxofaciens. B. subtilis was resistant only to eucalyptus honey.

The micellar extraction method (micellar mediated extraction (MME)) is an alternative method of classical extraction, which takes place with the participation of surfactants. In this method, instead of an organic solvent, a highly efficient solution of surfactants is used, which dissolves the desired component in hydrophobic micelles. Moreover, micellar extraction is often used for separating analytes from complex matrices, enriching analytes in environmental research, as well as for determining trace amounts of heavy metals or toxins in biological samples. The main goal of the presented study was to compare conventional extraction (using ethanol solutions) with micellar extraction (carried out with whey protein isolated (WPI) solutions and whey protein concentrated (WPC). The test material consisted of dried elderberry (Sambucus nigra) fruits. The comparison of the obtained extracts was performed by analyzing the contents of reducing compounds, flavonoid content, and the ability to reduce iron (III) ions in a system of three variables: Temperature, concentration and time. The obtained results clearly show that the factor influencing the efficiency of micellar extraction using WPC and WPI was time. The higher ability to reduce iron (III) ions was characterized by WPC protein extract as opposed to WPI extracts. The content of flavonoids in micellar extraction using protein extracts from WPC was higher than with the use of protein extracts from WPI.

ABSTRACT:Recently, interest in food of plant origin and its pro-health properties have increased. Plant products due to its significant antioxidant activity should be a constant part of the human diet. Elderberry is a The aim of this work was to extract bioactive components from elderberry (Sambucus nigra) fruits and flowers by means of various extraction solutions. The extraction solution were WPC (whey protein concentrate) and WPI (whey protein isolate) solution. Comparative extracts were also made using ethanol solutions and distilled water as control. Obtained extracts were analyzed by determination of: total reduction capacity using Folin-Ciocalteu reagent, flavonoid content, antioxidant activity using DPPH reagent. In WPC and WPI protein extracts, the extraction of bioactive components is more efficient than in the case of water extraction. This could be seen at the lowest concentration of both WPI and WPC.

The aim of the work was to compare the microwave-assisted extraction of coriander, black cumin and milk thistle seeds with the conventional process of extraction. Before the extraction material was crumbled, sieved and defatted. Obtained extracts were analyzed by means of the content of the antioxidants using ABTS, DPPH, Folin-Ciocalteu methods as well as the content of silibinin by HPLC (in case of milk thistle). By using these methods the content of reducing compounds, ability to scavenge free radicals and antioxidant capacity was evaluated in each case. It was shown that for the black cumin and milk thistle more effective was microwave extraction, but for the coriander conventional seems to be better. Extracts of black cumin and milk thistle obtained by microwave extraction have higher concentration of antioxidant compounds as compared to extracts from coriander. In case of coriander most effective a conventional extraction have been designated as more effective one.