The Use of a Thermal Process to Produce Black Garlic: Differences in the Physicochemical and Sensory Characteristics Using Seven Varieties of Fresh Garlic.

Black garlic (BG) is a product originating from fresh garlic (FG) and substantially differs in many aspects from FG due to the process called ageing. During this thermal process, the health-promoting properties of FG are enhanced, and the sensory traits are altered. However, very little is known about how the physicochemical properties of different FG varieties affect these properties of BG. Thus, the aim of this study was to investigate the influence of seven FG varieties subjected to the thermal process on the physicochemical parameters of BG. To prepare the BG samples, a fifteen-day ageing process involving a temperature gradient ranging from 30 to 82 °C was used. It was found that the antioxidant activity, the total polyphenol content, and the total soluble solids increased during ageing, while the pH level, moisture content, and lightness decreased in all the garlic varieties. The varieties of garlic differed in the studied traits significantly, both before (FG) and after ageing (BG). In the sensory analysis, significant differences between the BG varieties were observed only in the pleasantness of texture, while the remaining sensory descriptors (pleasantness of color, odor, taste and intensity of the garlic aroma, and overall acceptability) were not affected by variety. The correlations suggest that most of the FG's studied parameters in this study do not correlate with the properties of BG and cannot be used for the prediction of the quality of BG. Additionally, HPLC-MS/MS analysis revealed substantial changes in the composition of low molecular compounds.

Antifungal and Insecticidal Potential of the Essential Oil from Ocimum sanctum L. against Dangerous Fungal and Insect Species and Its Safety for Non-Target Useful Soil Species Eisenia fetida (Savigny, 1826).

The antifungal and insecticidal effect of the essential oil from Ocimum sanctum L. was evaluated using a model set of harmful organisms hazardous for health and the economy. Toxigenic and plant pathogenic filamentous fungi, including causal agents of human infections, were chosen as exemplary fungal groups-Fusarium verticillioides, Penicillium expansum and Aspergillus flavus. Spodoptera littoralis (African cotton leafworm), Culex quinquefasciatus (Southern house mosquito), the lymphatic filariasis vector and potential Zika virus vector, and the common housefly, Musca domestica were chosen as model insects. Major and minor active substances were detected and quantified using GC/MS analysis. Environmental safety was verified using the non-target useful organism Eisenia fetida. Significant antifungal and insecticidal activity, as well as environmental safety, were confirmed. The essential oil showed the highest efficacy against A. flavus according to MIC50/90, and against S. littoralis larvae according to LD50/90. The monoterpenoid alcohol linalool, t-methyl cinnamate, and estragole as phenylpropanoids were detected as effective major components (85.4%). The essential oil from Ocimum sanctum L. was evaluated as universal and significantly efficient, providing a high potential for use in environmentally safe botanical pesticides.

Thermal stability and bioavailability of bioactive compounds after baking of bread enriched with different onion by-products.

This study investigated the effects of the addition of onion waste fractions into gluten-free (GF) bread to promote its health benefits. 5% of the control (C) GF flour blend was replaced with three waste fractions in the form of: fried onion (FO), dried onion (DO) and onion peel (OP). Antioxidant activity, content of flavonols and total polyphenols of breads increased in the following order: C < FO < DO < OP. No differences were observed in sensory analysis. We found that quercetin glycosides, dimers and trimer in OP-bread, determined according to their mass spectra, decomposed during baking and released free quercetin, which points to their thermal instability. Cross-over study revealed that consumption of OP-bread significantly increased (p < 0.05) antioxidant activity of consumers' blood compared to control bread consumption, indicating good bioavailability of flavonols. Results suggest incorporation of OP into GF bread can increase its biological value with satisfactory sensory acceptance.

Variability in the Content of Trans-Resveratrol, Trans-ε-Viniferin and R2-Viniferin in Grape Cane of Seven Vitis vinifera L. Varieties during a Three-Year Study.

Grape canes are a waste product from viticulture that show potential as an industrially extractable source of stilbenes, which are valuable for medical and other purposes. In this work, grape canes collected in three consecutive years (2014-2016) at six different places in South Moravia, Czech Republic were extracted, and the contents of trans-resveratrol, trans-ε-viniferin, and r2-viniferin were determined by high-performance liquid chromatography. The study included three blue grape varieties of Vitis vinifera L. (Cabernet Moravia, Blaufränkisch, and Piwi variety Laurot) and four white grape varieties (Chardonnay, Green Veltliner, Piwi variety Hibernal, and Piwi variety Malverina). From the viewpoint of producing extracts with high stilbenes content, the Hibernal variety is clearly the best. The mean amounts of the stilbenes for this variety at all localities and for all three years were 4.99 g/kg for trans-resveratrol, 3.24 g/kg for trans-ε-viniferin, and 1.73 g/kg for r2-viniferin. The influence of vintage, locality, and variety on the amounts of stilbenes was studied using PCA analysis. In contrast to expectations, there was no strong impact of locality on stilbenes content. The differences were varietal for most varieties, regardless of the area of cultivation. Laurot and Hibernal varieties did differ significantly in that respect, however, as they exhibited clear dependence on location.

Changes of primary and secondary metabolites in barley plants exposed to CdO nanoparticles.

The environmental fate of airborne nanoparticles and their toxicity to plants is not yet fully understood. Pot-grown barley plants with second leaves developed were therefore exposed to CdO nanoparticles (CdONPs) of ecologically relevant size (7-60 nm) and concentration (2.03 ± 0.45 × 105 particles cm-3) in air for 3 weeks. An experiment was designed to test the effects of different treatments when only leaves (T1); leaves and soil substrate (T2); and leaves, soil, and water supply were exposed to nanoparticles (T3). A fourth, control group of plants was left without treatment (T0). Although CdONPs were directly absorbed by leaves from the air, a part of leaf-allocated Cd was also transported from roots by transpiration flow. Chromatographic assays revealed that CdONPs had a significant effect on total content of primary metabolites (amino acids and saccharides) but no significant effect on total content of secondary metabolites (phenolic compounds, Krebs cycle acids, and fatty acids). In addition, the compositions of individual metabolite classes were affected by CdONP treatment. For example, tryptophan and phenylalanine were the most affected amino acids in both analysed organs, while ferulic acid and isovitexin constituted the polyphenols most affected in leaves. Even though CdONP treatment had no effect on total fatty acids content, there were significant changes in the composition of saturated and unsaturated fatty acids in both the roots and leaves of treated plants. Although the results indicate the most pronounced effect in T3 plants as compared to T1 and T2 plants, even just leaf exposure to CdONPs has the potential to induce changes in plant metabolism.

Various extraction methods for obtaining stilbenes from grape cane of Vitis vinifera L.

Grape cane, leaves and grape marc are waste products from viticulture, which can be used to obtain secondary stilbene derivatives with high antioxidant value. The presented work compares several extraction methods: maceration at laboratory temperature, extraction at elevated temperature, fluidized-bed extraction, Soxhlet extraction, microwave-assisted extraction, and accelerated solvent extraction. To obtain trans-resveratrol, trans-ε-viniferin and r2-viniferin from grape cane of the V. vinifera variety Cabernet Moravia, various conditions were studied: different solvents, using powdered versus cut cane material, different extraction times, and one-step or multiple extractions. The largest concentrations found were 6030 ± 680 µg/g dry weight (d.w.) for trans-resveratrol, 2260 ± 90 µg/g d.w. for trans-ε-viniferin, and 510 ± 40 µg/g d.w. for r2-viniferin. The highest amounts of stilbenes (8500 ± 1100 µg/g d.w.) were obtained using accelerated solvent extraction in methanol.

Ultraviolet and photosynthetically active radiation can both induce photoprotective capacity allowing barley to overcome high radiation stress.

The main objective of this study was to determine the effects of acclimation to ultraviolet (UV) and photosynthetically active radiation (PAR) on photoprotective mechanisms in barley leaves. Barley plants were acclimated for 7 days under three combinations of high or low UV and PAR treatments ([UV-PAR-], [UV-PAR+], [UV+PAR+]). Subsequently, plants were exposed to short-term high radiation stress (HRS; defined by high intensities of PAR - 1000 µmol m(-2) s(-1), UV-A - 10 W m(-2) and UV-B 2 W m(-2) for 4 h), to test their photoprotective capacity. The barley variety sensitive to photooxidative stress (Barke) had low constitutive flavonoid content compared to the resistant variety (Bonus) under low UV and PAR intensities. The accumulation of lutonarin and 3-feruloylquinic acid, but not of saponarin, was greatly enhanced by high PAR and further increased by UV exposure. Acclimation of plants to both high UV and PAR intensities also increased the total pool of xanthophyll-cycle pigments (VAZ). Subsequent exposure to HRS revealed that prior acclimation to UV and PAR was able to ameliorate the negative consequences of HRS on photosynthesis. Both total contents of epidermal flavonols and the total pool of VAZ were closely correlated with small reductions in light-saturated CO2 assimilation rate and maximum quantum yield of photosystem II photochemistry caused by HRS. Based on these results, we conclude that growth under high PAR can substantially increase the photoprotective capacity of barley plants compared with plants grown under low PAR. However, additional UV radiation is necessary to fully induce photoprotective mechanisms in the variety Barke. This study demonstrates that UV-exposure can lead to enhanced photoprotective capacity and can contribute to the induction of tolerance to high radiation stress in barley.

Fungal bioremediation of the creosote-contaminated soil: influence of Pleurotus ostreatus and Irpex lacteus on polycyclic aromatic hydrocarbons removal and soil microbial community composition in the laboratory-scale study.

The aim of this study was to determine the efficacy of selected basidiomycetes in the removing of polycyclic aromatic hydrocarbons (PAH) from the creosote-contaminated soil. Fungi Pleurotus ostreatus and Irpex lacteus were supplemented with creosote-contaminated (50-200 mg kg(-1) PAH) soil originating from a wood-preserving plant and incubated at 15 °C for 120 d. Either fungus degraded PAH with 4-6 aromatic rings more efficiently than the microbial community present initially in the soil. PAH removal was higher in P. ostreatus treatments (55-67%) than in I. lacteus treatments (27-36%) in general. P. ostreatus (respectively, I. lacteus) removed 86-96% (47-59%) of 2-rings PAH, 63-72% (33-45%) of 3-rings PAH, 32-49% (9-14%) of 4-rings PAH and 31-38% (11-13%) of 5-6-rings PAH. MIS (Microbial Identification System) Sherlock analysis of the bacterial community determined the presence of dominant Gram-negative bacteria (G-) Pseudomonas in the inoculated soil before the application of fungi. Complex soil microbial community was characterized by phospholipid fatty acids analysis followed by GC-MS/MS. Either fungus induced the decrease of bacterial biomass (G- bacteria in particular), but the soil microbial community was influenced by P. ostreatus in a different way than by I. lacteus. The bacterial community was stressed more by the presence of I. lacteus than P. ostreatus (as proved by the ratio of the fungal/bacterial markers and by the ratio of trans/cis mono-unsaturated fatty acids). Moreover, P. ostreatus stimulated the growth of Gram-positive bacteria (G+), especially actinobacteria and these results indicate the potential of the positive synergistic interaction of this fungus and actinobacteria in creosote biodegradation.

Hydroxy-PCBs, methoxy-PCBs and hydroxy-methoxy-PCBs: metabolites of polychlorinated biphenyls formed in vitro by tobacco cells.

While the metabolism of polychlorinated biphenyls (PCBs) in plant cells is a rarely studied field, hydroxy-PCBs have been detected in several studies involving the use of various plant species. The ability of the tobacco (Nicotiana tabacum) callus culture WSC-38 to metabolize six dichlorobiphenyls under aseptic conditions was studied, and the resulting PCB metabolites were analyzed. WSC-38 cultures were cultivated with individual dichlorinated PCB congeners. The metabolites were identified based on mass spectra characteristics after gas chromatography separation. In addition, metabolites of PCB 9 (2,5-dichlorobiphenyl) were identified by comparing their retention characteristics with the available standards. In most cases at least two hydroxy-PCBs were produced from each parent PCB. Methoxy-PCBs and hydroxy-methoxy-PCBs were other groups of metabolites produced. To the best of our knowledge, ours is the first report to determine the presence of methoxy- and hydroxy-methoxy-metabolites of PCBs in plants. The role of the O-methyltransferases (OMTs) in the methylation of hydroxy-PCBs is discussed. As methoxy-metabolites of acetophenone were found among our samples, we posit that the OMTs responsible for the methylation of these compounds are also involved in the metabolism of PCBs in cultures of WSC-38.