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Harvesting of white hop shoots might be justified if they can be shown to be beneficial to human health. The aim of the present study is to determine the effects of hop cultivars and year of production on total phenolics, antioxidant potential, microelements and pesticide residues. Biomass per plant was highly variable among the cultivars (3.1-7.1 g dry mass per plant) and depended on hop cultivar and year (2009-2011). Total phenolics as chlorogenic acid equivalents (CAE) on dry mass basis varied from 0.60 to 1.80 mg/g, and showed significant effects across hop cultivar and year. The radical scavenging activities of the samples collected in years 2010-2012 ranged from 11 to 19 μg CAE. Ferric reducing activity was

The biomass per plant and total phenolics (TPH) of ethanol extracts of 3 species of thyme, Thymus vulgaris , T. serpyllum , and T. citriodorus, and 3 varieties of basil (Ocimum basilicum ), Genovese, Thai, and Cinnamon, were investigated. All were grown organically. The 2 herbs that showed the greatest biomass were T. citriodorus ( 26.5 g/plant ) and O. basilicum var. Cinnamon (105 g/ plant). For these, total flavonoids (TFL), total flavones and flavonols (TFF), and total flavanones and dihydroflavonols (TFDH) were also determined for their ethanol extracts. Furthermore, the antioxidant potential (AOP) and antibacterial activity were determined against foodborne bacteria: Staphylococcus aureus , Listeria monocytogenes , Campylobacter jejuni , and verotoxin-producing Escherichia coli (VTEC). The highest TPH (36 mg chlorogenic acid equivalents per gram of fresh weight) was seen for T. citriodorus collected in 2010. The thyme ethanol extracts contained more TPH and TFL, and their subgroups of TFF and TFDH, than the ethanol extracts from basil, and had AOP comparable to the ethanol extracts from basil, although all of them were lower than the synthetic antioxidant, t-butylated hydroxytoluene. Drying of these herbs decreased TFF and TFDH, while TPH and TFL remained unchanged (for T. citriodorus ) or even increased (for Cinnamon basil), and AOP was higher than that of the ethanol extracts from the frozen herbs. The antimicrobial activities of these ethanol extracts depended mainly on the bacterial target. They were weak against gram-negative VTEC, while their effects against C. jejuni , S. aureus , and L. monocytogenes correlated with their TPH and chemical compositions.

Trans-resveratrol was added to ‘Blaufrankisch’ red wine to determine the changes in total phenolics, total anthocyanins, and antioxidant potential. The results of this first investigation were presented in Part I; the results of the sensory analyses are included here, in Part II. Addition of increasing concentrations of trans-resveratrol to the ‘Blaufrankisch’ red wine improved the intensity of color by ~7%. and also the stability of malvidin-3-glucoside. Surprisingly, these additions of trans-resveratrol affected the odor of the red wine. Correlations among the sensory attributes showed Pearson's coefficients for positive correlations among these parameters. The higher additions of trans-resveratrol to the red wine (150, 200 mg/L) showed significantly improved sensory scores for color and odor, compared to the no-addition control (p ≤ 0.05). The highest positive correlation was between flavor and overall acceptance (0.876), which reached statistical significance (p ≤ 0.01); the lowest Pearson's coefficient was between clarity and flavor (0.061). This study shows that trans-resveratrol increases the stability of the enriched ‘Blaufrankisch’ red wine, and improves the sensory acceptance.

The effects of extended maceration (13 days) were investigated for extraction of trans-resveratrol and other phenolics from grapes of cultivar ‘Blaufrankisch’, and then during the subsequent maturation of the wine (250 days). Total phenolics and three subgroups of phenolics were followed. The concentrations of total phenolics, total flavonoids, and total anthocyanins, but not of total nonflavonoids, increased with extended maceration, and then decreased after 250 days of maturation. Trans- and cis-resveratrol concentrations increased following extended maceration and maturation (6.5, 2.9 mg/L, respectively). The maximum polydatin concentration was reached after only 6 days of maceration (10.9 mg/L). The antioxidant potential of the must increased following extended maceration (12.3 mmol DPPH2/L), and then remained unchanged for the red wine after maturation. Addition of trans-resveratrol to the red wine and into model solutions showed increased solubility and stability of trans-resveratrol in the red wines over the model solutions. Minor increases in antioxidant potential and better stability of malvidin-3-glucoside were also seen.

Bilberries processed into spreads represent an important source of anthocyanins if these remain rich in the final product. The effects of thermal processing were studied with non-ground and ground bilberries processed into spreads according to industrial and home-made procedures. Samples were analysed by LC-DAD-MS/MS and LC-MS. The spreads had 28-60% less total phenolics, 4-62% less anthocyanins, and 1-fold to 2-fold more phenolic acids and total flavonols than the bilberries, but approximately equal flavanols. The home-made spread from ground bilberries had ca. 26% higher antioxidant activity. Delphinidin 3-glucoside and cyanidin 3-glucoside were taken through the two spread procedures, with their degradation to gallic acid (38-57%), protocatechuic acid (1-2%) and 2,4,6-trihydroxybenzaldehyde determined. The amounts of gallic and protocatechuic acids did not reflect well for anthocyanin degradation. The industrial spread procedure with non-ground bilberries is a more suitable procedure to maintain the final content of anthocyanins.

The leaves of the hop plant (Humulus lupulus L.) are an agricultural by-product that is not currently being exploited. This study compared two hop cultivars cv. ‘Aurora’ and cv. ‘Hallertauer Magnum’ from four different hop-growing regions (Žalec, Slovenia; Leutschach (Kranach), Austria; Hull, Germany; Žatec, Czech Republic). The leaves and cones were collected and their total phenolics and the antioxidative and antimicrobial activities of their ethanol extracts were determined. Samples were collected three years in succession (2008–2010). Total phenolics ranged from 0.099 to 0.542 mg CAE/mL for the leaf extract and from 0.738 to 1.734 mg CAE/mL for the cones, which had both higher levels and greater variability of phenolics. The leaves had much lower DPPH radical scavenging activity. Their IC50 of approximately 0.020 mg/mL was much higher than the cones’ extracts (0.005 to 0.010 mg/mL) regardless of the year and of the growing location. The best reducer was the extract from the Aurora leaves collected in the Czech Republic in 2010, which reduced 0.117 mL/μg of ferric ions in 25 min. Antimicrobial activity against gram positive Staphylococcus aureus was extraordinary for all hop cones extracts (minimal inhibitory concentrations, MICs 0.16 mg/mL) against gram negative Escherichia coli O157:H7 was observed for hop cones and leaves extracts. The results of the profile analysis showed the caffeic acid peak at tr = 35.1 min for the leaves, while the cones had no such peak at that retention time.

We investigated how the structural properties of (+)-catechin, (−)-epicatechin, (−)-epigallocatechin (EGC) and (−)-epigallocatechin-3-gallate (EGCG) and butylated hydroxytoluene (BHT) correlate with structural changes of phosphatidylcholine plus sphingomyelin (2.4:1) model lipid membranes. Changes were measured by fluorescence anisotropy, electron paramagnetic resonance, and differential scanning calorimetry. Two fluorophores and two spin probes were used to monitor membrane characteristics close to water–lipid interface and in the middle of the bilayer. The data obtained were correlated to the amount of bounded compounds, the number of H-bonds, and the topological polar surface area (TPSA) of the compounds. These correlations reflect the behaviours of (+)-catechin, (−)-epicatechin, EGC, EGCG and BHT. Our results confirm that phenolics studied here are bounded to a membrane surface predominantly via hydrogen bonds, while BTH is inserted into the lipid bilayer.

Phenolics from bilberries ( Vaccinium myrtillus L.) sampled from seven different locations and highbush blueberries ( Vaccinium corymbosum L.) from one location in Slovenia were analyzed. In samples of both species 15 anthocyanins were identified by LC-MS/MS. Their contents were expressed as cyanidin 3-glucoside equivalents (C3GE); bilberries contained 1210.3 ± 111.5 mg C3GE/100 g fw and blueberries 212.4 ± 14.1 mg C3GE/100 g fw. Glycosides of delphinidin and cyanidin were predominant (488.5 vs 363.6 mg C3GE/100 g fw) in the bilberries and glycosides of malvidin (108.0 vs 100.8 mg C3GE/100 g fw) in the blueberries, whereas the contents of peonidin were lowest (74.5 vs 4.8 mg C3GE/100 g fw) in both berries. The contents of flavanols, flavonols, phenolic acids, and stilbenes were determined by LC-MS. For the first time, rutin was identified (bilberries, 0.2 ± 0.0 mg/100 g fw; blueberries, 3.1 ± 0.1 mg/100 g fw). Chlorogenic acid (as 3-caffeoylquinic acid) was the most abundant among the phenolic acids (23.1 ± 1.0 mg/100 g fw in bilberries and 70.0 ± 3.4 mg/100 g fw in blueberries). Statistical analysis shows that the content of 27 individual flavonoids, phenolic acids, and stilbenes can be used to identify the picking region of these Slovenian bilberries.

The influence of the p-coumaric, caffeic and ferulic phenolic acids, and their corresponding styrenes, on structural properties of a model lipid membrane was investigated by differential scanning calorimetry and fluorimetry. The phenolic acids were seen to have smaller effects, compared to their styrenes, on the temperature and enthalpy of the main phase transition (gel-to-liquid) of extruded large unilamellar liposomes prepared from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine lipids. A slight thermal and enthalpy destabilisation of the liposomes was seen with the phenolic acids at a lipid:acid molar ratio of 1:1. In contrast, their styrenes had higher destabilisation effects on the enthalpy of the phase transition. For fluorescence spectroscopy with 1,6-diphenyl-1,3,5-hexatriene as the membrane probe, the polarisation measurements showed that the styrenes, which are less polar than their corresponding acids, had greater effects on lipid membrane structure. The correlations between the structural properties of these compounds and their effects on membrane structure are discussed.

The membrane fluidity characteristics of multilamellar (MLV) and extruded liposomes prepared with kaempferol (K), kaempferol-3-glucoside (KG), (−)-epigallocatechin (EGC) or (−)-epigallocatechin-3-gallate (EGCG) are presented. Kaempferol caused the highest increase in fluorescence polarisation of DPH in both liposomes (other compounds had not) indicating that K with nK/nLip below 0.2 or 0.1 decreased the membrane fluidity, while at higher molar ratios the membrane fluidity increased. EPR measurements with MLV and spin probes MeFASL(10,3) and MeFASL(2,11) showed a significant decrease in fluidity in the upper part of the membrane for all flavonoids measured, and in the core of the membrane an increase in fluidity for EGCG and EGC. Computer simulation of the EPR spectra showed that the membrane of the MLV used was composed of at least three coexisting domain types with different fluidity and that the order parameter of the most ordered domains is responsible for membrane fluidity alterations.

Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1111 Ljubljana, Slovenia, E-mails: milica.kac@bf.uni-lj.si; veronika.abram@bf.uni-lj.si * Author to whom correspondence should be addressed; E-mail: barbara.ceh-breznik@guest.arnes.si Received: 30 May 2007; in revised form: 20 August 2007 / Accepted: 9 September 2007 / Published: 12 September 2007 Abstract: The effect of water supply – especially of drought stress – on the content of some secondary metabolites in hops ( Humulus lupulus L.) was studied. The experiment took place in 2006. Some relevant data from 2005 were included for comparison. Leaves and cones of nine hop cultivars grown under field conditions as well as in a pot experiment under three water regimes were analyzed. The cultivars ranged from those most grown in Slovenia to promising crossbreed being tested. Leaves were sampled from July 18, 2006 to August 18, 2006, while cones were picked in the time of technological maturity. Standard analytical methods were applied to determine the contents of xanthohumol, polyphenols and α-acids in hop leaves and hop cones. The contents of the secondary metabolites in question depended more on the cultivar under investigation than on the water supply, at least as far the growing conditions for a relatively normal development of the plant were met. Keywords: Xanthohunol, polyphenols, hops, Humulus lupulus , water supply

The dietary sources of CoQ10 and the evaluation of CoQ10 in dairy products were characterized. For quantitation of CoQ10 in food samples, 2 liquid chromatography (LC) methods with UV and mass spectrometry (MS) detections were developed. LC with UV detection was performed at 25°C on a Hyperclone ODS 5 μm 150 × 4.6 mm column with mobile phase consisting of methanol-ethanol-2-propanol (70 + 15 + 15, v/v/v). Flow rate was 1.0 mL/min. Retention time of CoQ10 was 10.9 ± 0.1 min. The method was sensitive [limit of detection (LOD) = 0.2 mg/kg], reproducible [relative standard deviation (RSD) = 3.0%), and linear up to 25 mg/kg (R > 0.999). LC/MS analysis was performed on a LUNA C18 3 μm, 150 × 4.6 mm column, using mobile phase consisting of ethanol-dioxane-acetic acid (9 + 1 + 0.01, v/v/v), flow rate was 0.6 mL/min, and the retention time of CoQ10 was 4.1 ± 0.1 min. Identification and quantitation were performed with a Finnigan-LCQ mass detector in positive atmospheric pressure chemical ionization mode. Mass spectra were obtained in selected-ion monitoring mode; molecular mass (M+H)+m/z 863.4 ± 1 was used for quantitative determination. MS detection is more sensitive than UV detection (LOD = 0.1 mg/kg), less reproducible (RSD = 4.0%), and linear in selected range. Analytical recoveries are 75–90% and depend on the ratio between the amount of fat in the matrix and the concentration of CoQ10 in the sample. Some soybean milk products were analyzed together with different cow, goat, and sheep milk products. Concentrations obtained with LC and LC/MS were compared with a few accessible results available from the literature. Concentrations varied from 0 ppm in soybean milk to nearly 2 ppm in fresh milk from local farms.

The aim of this research was to evaluate the color, firmness, and total phenolic (TP) content in tomatoes according to cultivar and growing conditions. Cultivars with oval, elongated, round, and cherry-shaped fruits of determinate tomato were grown in Mediterranean (Dragonja Valley) and continental regions. Experiments in the continental region were conducted outdoors (Ljubljana-field) and under a low tunnel (Ljubljana-tunnel). Results indicated that the color and firmness were significantly influenced by the typology of the cultivars and by the maturity stage associated with the climatic conditions. Oval, elongated, and cherry fruits had darker and more intensely red fruit skins, with significantly higher a* and lower L* values than round fruits. The firmness of oval and elongated fruits was also higher than the firmness of round fruits. Fruits harvested in Dragonja Valley and the Ljubljana-tunnel location reached a higher level of maturity and were classified in the red maturity class (a*/b* > 0.95), compared to the fruits from the Ljubljana-field location, where tomatoes were classified in the light red maturity class (0.65 > a*/b* > 0.95). Variation in total phenol (TP) content was evaluated in regards to different microclimatic conditions of the Ljubljana locations, outdoors and under the low tunnel. TP content, expressed as chlorogenic acid, ranged from 1.89 mg 100 g-1 to 3.28 mg 100 g-1 fresh weight (fw) in field-grown tomatoes and from 2.31 mg 100 g-1 to 4.90 mg 100 g-1 in tunnel-grown tomatoes. Cherry tomato had a significantly higher content of TP, ranging from 8.60 mg 100 g-1 fw in field-grown fruits to 10.39 mg 100 g-1 fw in tunnel-grown fruits. Although the differences between TP content in tomato fruits, regarding the microclimatic environment, were not statistically significant, the increase in TP content in tunnel-grown tomato fruits could be a plant response mechanism to thermal stress.

The aim of this research was to evaluate the color, firmness, and total phenolic (TP) content in tomatoes according to cultivar and growing conditions. Cultivars with oval, elongated, round, and cherry-shaped fruits of determinate tomato were grown in Mediterranean (Dragonja Valley) and continental regions. Experiments in the continental region were conducted outdoors (Ljubljana-field) and under a low tunnel (Ljubljana-tunnel). Results indicated that the color and firmness were significantly influenced by the typology of the cultivars and by the maturity stage associated with the climatic conditions. Oval, elongated, and cherry fruits had darker and more intensely red fruit skins, with significantly higher a* and lower L* values than round fruits. The firmness of oval and elongated fruits was also higher than the firmness of round fruits. Fruits harvested in Dragonja Valley and the Ljubljana-tunnel location reached a higher level of maturity and were classified in the red maturity class (a*/b* > 0.95), compared to the fruits from the Ljubljana-field location, where tomatoes were classified in the light red maturity class (0.65 > a*/b* > 0.95). Variation in total phenol (TP) content was evaluated in regards to different microclimatic conditions of the Ljubljana locations, outdoors and under the low tunnel. TP content, expressed as chlorogenic acid, ranged from 1.89 mg 100 g-1 to 3.28 mg 100 g-1 fresh weight (fw) in field-grown tomatoes and from 2.31 mg 100 g-1 to 4.90 mg 100 g-1 in tunnel-grown tomatoes. Cherry tomato had a significantly higher content of TP, ranging from 8.60 mg 100 g-1 fw in field-grown fruits to 10.39 mg 100 g-1 fw in tunnel-grown fruits. Although the differences between TP content in tomato fruits, regarding the microclimatic environment, were not statistically significant, the increase in TP content in tunnel-grown tomato fruits could be a plant response mechanism to thermal stress.

Polyphenols were isolated from sliced fresh leaves of Sempervivum tectorum. After 21 h of extraction by methanol and removal of chlorophyll, ethyl acetate was used to separate oligomeric and polymeric polyphenols: 0.07% of oligomeric and 0.13% of polymeric polyphenols were found. After acidic hydrolysis of the oligomeric polyphenols, it was established by TLC, HPLC, and FAB mass spectra that kaempferol was the unique aglycon of the three main oligomeric constituents of S. tectorum. Paper chromatography suggested delphinidol to be the only anthocyanidin detectable in the material obtained by acidic hydrolysis of the polymeric polyphenol fraction. After Haslam degradation of the same polymeric polyphenol fraction, only 4-thiobenzyl-(-)-epigallocatechin and 4-thiobenzyl-(-)-epigallocatechin-3-gallate were found and tentatively identified. We concluded that procyanidins of B2 type could be the major components of the polymeric polyphenol fraction of this plant. Antimicrobial activity of Sempervivum L. leaves against six of seven selected microorganisms was observed.

Berry anthocyanins have pronounced health effects, even though they have a low bioavailability. The common mechanism underlying health protection is believed to relate to antioxidant activity. Berry extracts, chemically characterised for their phenolic content, were prepared from bilberries (Vaccinium myrtillus L.) and blueberries (Vaccinium corymbosum L.); the bilberry extract was further purified to obtain the anthocyanin fraction. The antioxidant activity of each extract was examined at the cellular level. For this purpose a specific assay, known as cellular antioxidant activity assay (CAA), was implemented in different cell lines: human colon cancer (Caco-2), human hepatocarcinoma (HepG2), human endothelial (EA.hy926) and rat vascular smooth muscle (A7r5). Here we show for the first time that anthocyanins had intracellularantioxidant activity if applied at very low concentrations (

The antioxidant properties of components of leaf extracts of the evergreen plant, Sempervivum tectorum (ST), have been evaluated using UV irradiated liposomal systems containing the spin trap 5-(diethoxyphosphoryl)-5-methyl-pyrroline-N-oxide. Decreases in free radical activity in the liposomal systems as measured by electron paramagnetic resonance (EPR) spectroscopy demonstrate that the lipophilic ST juice components, kaempferol (KA) and kaempferol-3-glucoside (KG) contribute significantly to the antioxidant properties of the juice. EPR spectral simulation established the presence of oxygen and carbon centered free radical adducts. The mixtures with low pH, citric and malic acid, and ST juice reveal increased EPR signals from oxygen centered radicals in comparison to the control, pointing to the important role of pH in oxygen radical formation. Parallel assays that measured thiobarbituric acid related substances confirm the antioxidant effects of KA and KG and explain the results of spin trapping experiments complicated by low pH's.

Sempervivum L. plants belong to the family of Crassulaceae (Swart, 1991), the subfamily Sempervivoideae (Stevens et al., 1992). They used to grow mainly in Southern Europe all the way from Spain to Asia Minor, but nowadays they are widespread in other parts of Europe also. Sempervivum is an evergreen plant with meaty juicy leaves. Plants can survive prolonged periods of drought and they are known to have CAM metabolism (Winter, Smith, 1996).

Camelina sativa is a cruciferous oilseed plant. With the aim of describing the general characteristics of the oil obtained from the seeds of plants grown in Slovenia and of comparing it to camelina oil from other countries we determined some physico-chemical properties, fatty acid composition, iodine and saponification value and followed its oxidative stability under different storage conditions. The density at 20 °C was (0.927 0.0001) g/cm3 and the refractive index reached 1.4756 0.0001 at 25 °C. The analysis of fatty acids showed 10.3 % of saturated and 55.8 % of polyunsaturated acids, with 16.9 % of linoleic (C18:2), 35.2 % of -linolenic (C18:33) and 1.6 % of erucic acid (C22:1). Determination of oxidative stability of this highly unsaturated oil revealed that the formation of primary oxidation products was affected by photooxidation. The peroxide value, PV, of fresh oil was (2.38 0.01) meq O2/kg, while after 1 month in daylight at room temperature PV reached (21.0 0.1) meq O2/kg. When stored in darkness PV was (8.12 0.08) meq O2/kg. In the fresh oil, the p-anisidine value, AV, was 6.2 0.1, after 11 months at room temperature 10.4 0.1, and after the same time at 8 °C in darkness 7.1 0.1. Susceptibility to oxidation of camelina oil was measured by the Rancimat test and expressed as the induction period. In fresh camelina oil the induction period was 4.8 h.