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Eight samples of propolis commercially available on south-eastern Poland’s beekeeping market were compared in terms of quality, chemical composition and biological activity, including antioxidant and antimicrobial properties. The organoleptic characteristics and physicochemical requirements indicated that only 50% of tested propolis samples was classified to class II regarding obligatory limits, while the others were out-class. A big variation in mineral composition was determined by the ICP-OES method but all samples were free of heavy metals (Pb, Cd and Ni). Although mesophilic bacteria, yeasts and moulds occurred in tested propolis (in general lower than 102 CFU/g), E. coli and spore-forming sulphite-reducing bacteria as well as Salmonella and Shigella bacteria were not detected. High antioxidant activity and total phenolic content for all samples was confirmed, which was correlated with antibacterial activity tested against E. coli ATCC 11775 strain. Additionally, the propolis sample with the strongest antibacterial activity (MIC 0.33 mg/mL) inhibited biofilm formation of S. aureus and S. epidermidis ATCC 35984 (MBIC 0.66 and 5.25 mg/mL, respectively). However, great variation in terms of antioxidant activity and HPLC polyphenolic profile were observed, and sakuranetin and pinobanksin were identified as the most effective antioxidant components. Moreover, the usefulness of ATR-FTIR spectra analysis was confirmed as a quick method for initial testing of propolis quality.

Mercury is a toxic metal which causes several serious health effects including kidney damage, anxiety depression and peripheral neuropathy, and because of its high volatility assessment in solid samples is problematic. In this study, forty-five samples of local Polish and imported honeys were analyzed by Direct Mercury Analyzer (DMA) for the determination of mercury content. The honey contamination was assessed regarding honey variety and country of origin. Hg level in all tested samples was found to not exceed the 0.81 μg/kg which was below 10% of the applicable law UE limit. Moreover, no statistically significant differences were found in the variety or geographical origin. The study concluded that the Direct Mercury Analyzer (DMA) instrument proved to be an excellent tool for screening mercury in honeys because of its simplicity, rapidity, low detection limit, accuracy and precision and no sample preparation.

The leaves and unripe fruits from 5 walnut clones were tested in terms of mineral composition, antioxidant activity, and the inhibitory effect on model urease. It has been shown that the leaves are richer in minerals and also have higher antioxidant potential than unripe fruits. HPTLC polyphenolic profiles of leaves extract were found more abundant in flavonoids regardless of the sample origin. Only green walnut extracts showed an effect as urease inhibitors. Higher antibacterial activity was observed against Staphylococcus aureus in comparison with Staphylococcus epidermidis. Both leaf and fruit extracts showed antibiofilm activity, up to 95% of biofilm inhibition. It was shown that all tested Juglans regia extracts can serve as a valuable antibacterial agent against staphylococci infections.

Crystallization of honey is a natural process occurring during honey storage and forces beekeepers to practice the decrystallization process, which mainly concerns honey heating. The aim of this study was to examine the possible use of ultrasounds or microwave radiation to delay the crystallization of honey and to liquefy crystallized honeys while maintaining their biological activity. Lime, acacia and multifloral honeys obtained from a local apiary were used. Fresh honeys were pretreated through ultrasounds (40 kHz, for 5 and 20 min) or microwaves (800 W, 4 x 30s) in order to obtain samples U5, U20 and M, respectively. Experimental and control samples were stored for twelve months at room temperature (20±2°C) without light. Crystallized honey was liquefied through the same methods of ultrasounds (sample U5* and U20*) and microwaves (sample M*). Naturally crystallized honeys were used as the controls. For fixed (U5, U20 and M) and decrystallized (U5*, U20*, M*) honeys, the water content (refractometrically), antioxidant properties (DPPH method), total phenolics content (Folin-Ciocalteu method) and enzymatic activity (diastase, α-glucosidase, β-galactosidase and α-mannosidase) were determined. The analyzed physicochemical parameters for both fixed and liquefied honeys did not differ significantly (P>0.05) in comparison to the control honey. Moreover, the decrystallization process increased the antioxidant activity of all tested honeys. The smallest changes in honey properties to ultrasonic treatments were observed, and this method was recommended to delay the crystallization process and significantly accelerate the liquefaction time of solid honeys without compromising its quality.

The aim of this study was to check the impact of the addition of selected flavoring herbs on the organoleptic and antioxidant properties of homemade tofu, as well as the possibility of its storage extension by freezing. The optimization of homemade tofu production based on organic soy and the enrichment (2% w/w) of obtained tofu with dried plant additives (wild garlic, basil, Herbes de Provence, black cumin seeds, and dried cranberries) was performed. The manufactured tofu was compared to commercial tofu (control) in terms of antioxidant activity, total polyphenol content, and polyphenol profile using thin-layer chromatography (HPTLC). Moreover, the texture profile and organoleptic assessment of the compared products were performed. The antioxidant and texture parameters were also controlled in tofu fixed by different methods: cold herbal infusion and prolonged freezing of vacuum-packed products. It was shown that homemade tofu was characterized by better sensory and texture properties than commercial product. Moreover, the introduction of plant additives to tofu increased the antioxidant activity and the content of polyphenols in the final product; the greater the activity of the herbs used, the higher the degree of tofu enrichment was achieved. In terms of all analyzed parameters, cranberries and Herbes de Provence additives to tofu were found to be the first choice. It was found that the addition of herbs to tofu allowed us to create new sensory features, enhanced the pro-healthy value, and extended the storage time. Due to no significant changes in texture and antioxidant properties of frozen tofu, as well as its acceptable microbial quality, freezing vacuum-packed tofu can be recommended as a beneficial way to extend the storage time at home condition. The addition of herbs allows for the design of new versions of tofu in accordance with consumer preferences, and the proposed packaging method can be applied on an industrial scale. [ABSTRACT FROM AUTHOR]

The transfer of toxic metals from soil to honey was studied based on two different areas of the Podkarpackie region located in the south-east part of Poland: U-urbanized and E-ecologically pure. The metal content was determined using the ICP-OES method with prior microwave mineralization of the soil, plant (goldenrod, dandelion, rapeseed, tilia and fir), bee bodies and honey samples collected from 10 sampling points (U-5 and E-5). The impact of soil pH on heavy metal mobility was also evaluated. It was found that Podkarpackie soils are less contaminated with heavy metals as compared to other regions of Poland and only in the case of cadmium an enhancement of the natural background level was observed. The migration of heavy metals, especially cadmium, in the soil-plant-bee-honey food chain was accelerated by soil acidity (p0.05). Based on bioaccumulation factors, goldenrod and dandelion plants were confirmed as cadmium accumulators. It was also confirmed that the bodies of bees act as an effective barrier to the migration of heavy metals from the environment to honey, due to this, honey is free from these metals and safe for human consumption.

Four samples of fir honeydew honey from Podkarpackie labeled with a Protected Designation of Origin symbol were tested in terms of their physicochemical parameters, antioxidant, and antibacterial effects, as well as their anti-migration properties against a breast cancer cell line (MCF-7) and fibroblasts. The results confirmed the high quality of tested samples regarding the obligatory parameters, as well as the additional indicators used (antioxidant and enzymatic activity), compared to representative rapeseed honey. Among the tested bacterial strains, the greatest effectiveness was demonstrated against Klebsiella pneumoniae and Streptococcus spp. Moreover, the results obtained in the urease inhibition in vitro test suggested the potential use of honeydew honey in the treatment of urease-positive bacterial infections. For the first time, using a scratch test it was found that the Podkarpackie honeydew honey efficiently affected the migration of cancer breast cells, whereas it only slightly inhibited the movement of normal fibroblasts. It can be suggested that the quality of honey guaranteed by the Protected Designation of Origin label could be the key factor of honeydew honey's bioactivity and its potential medicinal use. [ABSTRACT FROM AUTHOR]

The aim of the study was to obtain a dye from black elder fruits and flowers and to study their potential in production of jellies with high antioxidant activity. Three dyes were produced by lyophilization of aqueous extracts: (1) fruits dye (F), (2) flowers dye (FL), and (3) fruits and flowers dye (F + FL). Their polyphenol profiles were compared by means of ultra-performance liquid chromatography (UPLC). The antioxidant activity [ferric reducing/antioxidant power assay (FRAP) and DPPH radicals scavenging test and total phenolics were compared by spectrophotometric methods. Jellies were produced from agar and gelatin with the addition of three obtained dyes, and their antioxidant water- and lipid soluble fractions were tested with a Photochem device. Results indicated that black elder fruits are rich in anthocyanins, especially cyanidin-3-O-sambubioside (7.56 mg/g d.w.), while flowers are rich in polyphenols, especially chlorogenic acid (2.82 mg/g d.w.) and rutin (4.04 mg/g d.w.). FL dye exhibited higher antioxidant activity compared to F dye (for about 30−40%), regardless of the used method, whereas F + FL dye was characterized by intermediate antioxidant activity. Jellies produced with the addition of FL dye had better antioxidant properties but unattractive color and unpleasant taste, but the use of F + FL dye created a product of favorable organoleptic properties and antioxidant activity comparable to jellies with F dye addition.

Copyright of Zywnosc is the property of Polish Society of Food Technologists - Scientific Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Zywnosc is the property of Polish Society of Food Technologists - Scientific Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)