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The Carpathian lingonberry, raspberry and blackberry fruit extracts feature variable antimicrobial efficiency
27-32Views:362Wild berry is an excellent source of phytonutrients and/or bioactive compounds associated with significant therapeutic properties, so that they have been utilized in folk medicine and traditional nutrition throughout centuries. Multiple health-promoting effects, such as anti-inflammatory, anti-diabetic, anti-heart and coronary disease properties were attributed to such wild berries. It has also been proved that berries could feature antimicrobial effects that could be of a great importance for the prevention of food-feed poisoning and fighting back antibiotic resistance.
In this study, we investigated the antimicrobial properties of lingonberry (Vaccinium vitis-idaea), raspberry (Rubus idaeus) and blackberry (Rubus fruticosus) crude and ethanolic extracts prepared from fruits obtained from the spontaneous flora of Eastern Carpathian Mountains situated in Transylvania. The antimicrobial effect of crude and alcoholic extracts were assessed on four Gram-negative, five Gram-positive bacteria and one yeast species using the agar diffusion method. The studied bacteria can cause food or feed spoilage and foodborne diseases. Our results indicate the significant inhibitory effect of lingonberry extracts in the case of Gram-negative bacteria like Proteus vulgaris and Salmonella Hartford, while among Gram-positive bacteria the strongest inhibitory effect was observed for Bacillus species like B. cereus, B. subtilis, B. mojavensis and Micrococcus luteus. The raspberry and blackberry extracts featured milder inhibitory effects in the case of the studied bacteria species. Furthermore, we have studied the crude or ethanolic extract combinations associated antimicrobial effects synergistic/additive or antagonistic properties. Interestingly, the triple and double ethanolic extract mixes had stronger antimicrobial properties, whereas the crude extract mixes showed relatively reduced effects, if any. Our results indicate that the antimicrobial activity of studied fruit extracts obtained from wild berries can vary upon the applied extraction method and their combination formulae, so that all these considerations must be taken into account when such fruit extracts are considered for foodstuff development.
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The effect of the preparation method on the physical and chemical characteristics of propolis tinctures
163-168Views:286The effect of the preparation method was examined with regards to the physical and chemical characteristics of the propolis tincture, namely the extraction time and the ethanol content of the extraction solvent to the dry matter, polyphenol, flavonoid, phosphorus, calcium and copper concentration, respectively. The dry matter, the polyphenol and the flavonoid content were the lowest in the water extract of the propolis; however, significant increase was noticed depending on the extraction time. Significantly higher concentrations were found in 50 V/V% tinctures. The highest dry matter and flavonoid contents were analysed in 100 V/V% tinctures, whereas highest polyphenol content was found in 80 V/V% tinctures. However, the differences were not significant in several cases between latter tinctures. Moreover, the increase was not determined in some cases depending on the extraction time. Phosphorus and calcium concentrations were decreased depending on the increasing ethanol content, whereas copper concentration was increased up to 80 V/V%. Higher increase was found in the case of 0 and 50 V/V% extracts than in 80 and 100 V/V% tinctures. Moreover, in latter cases, no significant differences were found on several occasions, depending on the extraction time. There was no connection between the flavonoids and the calcium as well as the phosphorus content, whereas flavonoids may be made complex with copper. However, the amount of the possible complex was negligible.