Flax (Linum usitatissimum L.) is an annual plant cultivated in moderate climates. Although the ge... more Flax (Linum usitatissimum L.) is an annual plant cultivated in moderate climates. Although the genus Linum contains about 230 species, Linum usitatissimum is the only species which fulfills a commercial function, serving as a fiber donor for the textile industry and the production of linseed oil. The flax breeding is often limited due to the decrease in yield caused by fungi infection. The ectopic expression of a potato b-1,3-glucanase cDNA in flax has improved the plant's defence against pathogen. The resistance of transgenic lines against Fusarium oxysporum and Fusarium culmorum was about threefold higher than for the non-transformed plants. In an in vitro experiment the transgenic plant extract inhibited fungi growth and the inhibition was abolished by extract heating and anti-b-glucanase antibody treatment. By further investigation into the molecular basis of transgenic flax resistance, the metabolic profiling of the plant was performed. The significant decrease in the content of carbohydrate, fatty acids and organic acids and the increase in the level of selected amino acids, polyamines and antioxidant were revealed. What is interesting is that the transgenic plants showed a significant decrease in lignin content, which may lead to the improvement of flax fibre retting. q
The aim of this study was to determine selected phytochemicals in berries of eight sea buckthorn ... more The aim of this study was to determine selected phytochemicals in berries of eight sea buckthorn (Hippophae1 1 rhamnoides subsp. mongolica) cultivars, including lipophilic and hydrophilic compounds. In the experiment chromatographic 12 analyses, GC (phytosterols and fatty acids), UPLC-PDA-FL, LC-MS (polyphenols), and HPLC (L-ascorbic acid), as well 13 spectrophotometric method (total carotenoids) were used. The lipid fraction isolated from whole fruit contained 14 phytosterols 14 (major compounds β-sitosterol > 24-methylenecykloartanol > squalene) and 11 fatty acids in the order MUFAs > SFAs > 15 PUFAs. Carotenoids occurred in concentrations between 6.19 and 23.91 mg/100 g fresh weight (fw) (p < 0.05). The major 16 polyphenol group identified in berries was flavonols (mean content of 311.55 mg/100 g fw), with the structures of isorhamnetin 17 (six compounds), quercetin (four compounds), and kaempferol (one compound) glycosides. Examined sea buckthorn cultivars 18 were characterized also by a high content of L-ascorbic acid in a range from 52.86 to 130.97 mg/100 g fw (p < 0.05). 19
Iron-induced oxidation of (+)-catechin in a wine-like solution yielded typical products, includin... more Iron-induced oxidation of (+)-catechin in a wine-like solution yielded typical products, including colourless and yellow compounds. Structural characterization of the major colourless one indicated that it is a dimer, in which flavanol units are linked through a carboxy-methine bridge. Unlike what might be expected, the structure showed that oxidation does not affect catechin directly, but tartaric acid, to give glyoxylic acid, which then reacts with two flavanol units. From a mechanistic point of view, the reaction resembles, once glyoxylic acid is formed, that of acetaldehyde-induced condensation well documented in enology. Thus, an ion series (up to trimer) was detected by mass spectrometry in the model solution. On the other hand, yellow products formed from colourless ones, especially from that isolated, suggests that a second pathway contributing to browning competes with polycondensation reactions. ~, 1997
Compounds contained in fruits and leaves of blackcurrant (Ribes nigrum L.) are known as agents ac... more Compounds contained in fruits and leaves of blackcurrant (Ribes nigrum L.) are known as agents acting preventively and therapeutically on the organism. The HPLC analysis showed they are rich in polyphenol anthocyanins in fruits and flavonoids in leaves, that have antioxidant activity and are beneficial for health. The aim of the research was to determine the effect of blackcurrant fruit and leaf extracts on the physical properties of the erythrocyte membranes and assess their antioxidant properties. The effect of the extracts on osmotic resistance, shape of erythrocytes and hemolytic and antioxidant activity of the extracts were examined with spectrophotometric methods. The FTIR investigation showed that extracts modify the erythrocyte membrane and protect it against free radicals induced by UV radiation. The results show that the extracts do not induce hemolysis and even protect erythrocytes against the harmful action of UVC radiation, while slightly strengthening the membrane and ...
The aim of the study was to determine changes incurred by polyphenolic compounds from selected fr... more The aim of the study was to determine changes incurred by polyphenolic compounds from selected fruits in the lipid phase of the erythrocyte membrane, in liposomes formed of erythrocyte lipids and phosphatidylcholine liposomes. In particular, the effect of extracts from apple, chokeberry, and strawberry on the red blood cell morphology, on packing order in the lipid hydrophilic phase, on fluidity of the hydrophobic phase, as well as on the temperature of phase transition in DPPC liposomes was studied. In the erythrocyte population, the proportions of echinocytes increased due to incorporation of polyphenolic compounds. Fluorimetry with a laurdan probe indicated increased packing density in the hydrophilic phase of the membrane in presence of polyphenolic extracts, the highest effect being observed for the apple extract. Using the fluorescence probes DPH and TMA-DPH, no effect was noted inside the hydrophobic phase of the membrane, as the lipid bilayer fluidity was not modified. The p...
Three flavonoids of pharmaceutical importance-baicalein, baicalin, and wogonoside-were isolated f... more Three flavonoids of pharmaceutical importance-baicalein, baicalin, and wogonoside-were isolated from a Chinese medicinal plant Scutellaria baicalensis Georgi and studied by 13C NMR in solution and solid state. Two-dimensional (2D) NMR spectroscopy in the liquid phase and dipolar dephasing (DD) experiments in magic-angle spinning (MAS) spectra enabled the assignment of 13C resonances. The cross-polarization (CP) time constants T(CH) and relaxation times T(H) (1rho) were obtained from the variable-contact time experiments. The principal elements of the 13C chemical shift tensor were determined in the spectra recorded under slow sample spinning (2 kHz) using phase-adjusted spinning sideband (PASS)-2D NMR technique, and were verified by density functional theory gauge-independent atomic orbital (DFT GIAO) calculations of shielding constants. Analysis of the 13C delta(ii) and comparison with shielding parameters calculated for different conformers of compounds 1-3 enabled the selection of the most reliable geometry in the solid phase. In all three compounds, an intramolecular hydrogen bond C5--OH...=C4 is formed; the existence of baicalein and baicalin with &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;anticlockwise&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; orientation of OH groups is more probable.
The stability of phenolic compounds of three strawberry cultivars was evaluated for changes durin... more The stability of phenolic compounds of three strawberry cultivars was evaluated for changes during prefreezing treatments, storage and various freezing and thawing conditions. Polyphenol content was determined by HPLC-DAD-FL. The sum of assayed polyphenolic (proanthocyanidin and monomeric flavan-3-ols, anthocyanins, ellagic acid, p-coumaric acid) represented 2858.4 mg/kg in Kent, 2893.1 mg/ kg in Elkat, and 2438.0 mg/kg in Senga Sengana. After freezing, 4.5-33.6% of polyphenols were lost; protective effects of prefreezing treatments were seen on anthocyanidins and proanthocyanidins: ascorbic acid was the most effective pretreatment, allowing retention of 3.9-27.5% of anthocyanins, and almost total recovery (3.9-23.9%) when associated with liquid nitrogen freezing. Pectin and sugar only allowed retention of 3.0-25.1% and 5.5-25.4% of the antocyanins, respectively. Thawing of the strawberries in a microwave oven (instead of 20 h at 20 C) had a further positive effect on retention of anthocyanins, proanthocyanins, (þ)-catechin and ellagic acid.
Journal of the Science of Food and Agriculture, 2007
Clear and cloudy apple juices from Idared and Champion varieties were studied for their radicalsc... more Clear and cloudy apple juices from Idared and Champion varieties were studied for their radicalscavenging effects. The polyphenolic content and composition of the juices before and after thiolysis were determined by high-performance liquid chromatography with diode array detection. Cloudy juices, especially that prepared from Champion variety, had a higher content of procyanidins than clear juices. Radical-scavenging activity was measured by electron paramagnetic resonance (EPR) spectroscopy using the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. All juices showed long-lasting radical-scavenging activity, and EPR spectra were recorded over time to follow the reaction kinetics. Scavenging of DPPH showed pseudo-first-order kinetics, which might be expected in the presence of polymerised antioxidants that prevent closer contact between the DPPH radical and hydroxyl groups. The content of polymeric procyanidins showed a linear dependence on the rate constant, suggesting that these compounds are mainly responsible for time-extended radical-scavenging activity. The antioxidant properties of apple juices were much better reproduced by EPR spectroscopy than by UV-visible measurements. The former method is especially sensitive to the concentration of polymerised or bound procyanidins, whilst the latter method requires transparent (clear) samples. Apple juices, especially cloudy ones, are a rich source of natural antioxidants that may be used in the pharmaceutical or food industry.
Flax (Linum usitatissimum L.) is a very important source of natural fibres used by the textile in... more Flax (Linum usitatissimum L.) is a very important source of natural fibres used by the textile industry. Flax fibres are called lignocellulosic, because they contain mainly cellulose (about 70%), with hemicellulose, pectin and lignin. Lignin is a threedimensional polymer with a high molecular weight, and it gives rigidity and mechanical resistance to the fibre and plant. Its presence means the fibres have worse elastic properties than non-lignocellulosic fibres, e.g. cotton fibres, which contain no lignin.
International Journal of Food Science & Technology, 2008
The purpose of the present study was to evaluate the effect of rhubarb juice addition and peeling... more The purpose of the present study was to evaluate the effect of rhubarb juice addition and peeling in apple pure´e production and storage on its phenolic composition, antioxidant activity and colour. The apple material used in this study was of two varieties: Sampion and Idared. The apple pure´es prepared in three variants (control pure´es, peeling pure´es and pure´es with 5% of rhubarb juice) were stored for 3 and 6 months at 30°C. Apple pure´es were investigated for their antioxidant activity, change of colour and contents of phenolic compounds plus the polymer procyanidins and degree of polymerization (DP). The preparation of pure´es from apples without peeling and the addition of rhubarb juice during pure´e preparation had significant influence on polyphenol content. The pure´e prepared from peeled apples of Idared variety had phenolic content 2.2 times lower than the control sample (non-peeled apples). The highest level of total polyphenols was found in Idared + rhubarb sample (129.82 mg 100 g )1 pure´e). The content of this compound in Idared control sample was more than 2.8 times lower than in Idared pure´es with rhubarb. The use of non-peeled Idared apples and 5% of rhubarb juice in pure´e preparation significantly increased polymeric procyanidins from 11.68 to 75.20 mg 100 g )1 and other phenolics from 9.23 to 54.62 mg ⁄ 100 g. This effect for Sampion apples was smaller. The procyanidins during pure´es storage were more stable in samples with rhubarb juice addition. The pure´e samples with the addition of rhubarb juice had higher antioxidant activity measured using ABTS (2,2¢azinobis-(3-ethylbenzthiazoline-6-sulphonic acid)) than pure´e samples without the addition (two times higher for Idared variety) of rhubarb juice. After 3 and 6 months of storage at temperature 30°C, the antioxidant capacity decreased in all pure´es. Rhubarb juice had only high and positive effect on L* value in the case of Idared variety. The results showed that all Sampion apple pure´es had higher L* values than Idared.
In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids w... more In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids was examined. In the first experiment, during 8 weeks, four diets without or with 0.1, 0.2 and 0.4% extract of flavonoid from grapefruit (from 0.05 to 0.2% DM pure flavonoids) were applied. In the second experiment, during 10 days, diets with oxidised fat (100 meq O 2 /kg) and without or with 0.4% extract of flavonoid were applied. The obtained results showed that the addition of 0.1-0.4% extract of flavonoid from grapefruit did not affect the diet intake and the body weight gain of rats, and slightly increased the antioxidative potential of serum (decreased the MDA content but had no significant effect on the PGx and SOD activities). The addition strongly affected functioning of the blind gut ecosystem causing an increased filling with contents, an increase in the intestinal wall mass and pH, as well as a decrease in the microbiological activity of b-glucuronidase and an increase in the a-galactosidase activity. #
In experiments on rats, five diets without or supplemented with polyphenol extracts from differen... more In experiments on rats, five diets without or supplemented with polyphenol extracts from different sources (flavons from skullcap, catechins from green tea, anthocyanins from chokeberry and condensed tannins from faba bean) were applied. Obtained results suggested that when catechin extracts were added to the diets in large amounts (0.8%), beneficial effects (reduction of total cholesterol and LDL fraction in serum) were observed, but also reduction in protein digestibility and protein efficiency ratio (from 94.6 to 93.1% and from 2.57 to 2.40, respectively), compared to the control group. All extracts decreased the activity of erythrocyte superoxide dismutase and increased the activity of alanine aminotransferase in the serum. Only the tannin extract decreased the content of calcium in femur. More profitable biological properties were found for catechin extract from green tea and flavons extract from skullcap, compared to anthocyanins from chokeberry and condensed tannins from faba bean. #
Effects of pomace maceration on yield, turbidity, cloud stability, composition of phenolics, anti... more Effects of pomace maceration on yield, turbidity, cloud stability, composition of phenolics, antioxidant activity and colour properties were studied, to evaluate the potential applicability of enzyme preparations in puree-enriched cloudy apple juice production. The yield of mixed juice and puree from pomace obtained in the enzymatic processing of apple ranged from 92.3% to 95.3%, significantly higher than the yield from the control without enzymatic pomace treatment (81.8%). Higher turbidity was obtained upon pomace treatment with Pectinex XXL and Pectinex Ultra SPL enzymes. The total content of phenolic compounds in apple pomace was higher than in raw juices (1520 mg/kg and 441 mg/L, respectively). The total polyphenol yields were higher in juices treated with Pectinex AFP L-4, Pectinex Yield Mash and Pectinex XXL, as compared to the control treatment. During 6 months of storage, a significant change was observed in the content of polyphenols, especially in procyanidin fractions.
The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chloroge... more The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chlorogenic acid was the most abundant acid (20.0 mg/100 g in microwaved Idared); other polyphenols identified in high concentrations included (À)-epicatechin, procyanidin B1 and B2; quercetin and cyanidin glycosides were found in minor concentrations. The Shampion purées had higher total phenolics (142 mg/100 g) and procyanidin B2 concentrations (17.3 mg/100 g) than the Idared ones, and polymeric procyanidins represented 41% of all polyphenols. Antioxidant capacities of the samples, determined by spectrophotometric methods and EPR spectroscopy, correlated well with the concentration of polyphenols. The antioxidant properties could be better represented by EPR than by UV-vis measurements. The latter require transparent (clear) samples whereas EPR can be a method of choice in the assessment of radical-scavenging activity of dense and cloudy apple purées. Our results support the putative high antioxidant value of apple purées and define their capacity in terms of the major constituents. Apple purées are a rich source of natural antioxidants, especially of chlorogenic acid and procyanidins.
Polyphenols were analyzed by HPLC after thioacidolysis of proanthocyanidins polymers and acid hyd... more Polyphenols were analyzed by HPLC after thioacidolysis of proanthocyanidins polymers and acid hydrolysis of phenolic acid esters. The predominant constitutive units of the procyanidins of Aruncus Silvester and Potentilla alba roots were (−) epicatechin, and ...
The significance of antioxidants in preventive medicine is well known. Increasing interest has be... more The significance of antioxidants in preventive medicine is well known. Increasing interest has been devoted to naturally occurring compounds–polyphenols–because of their beneficial health effects. The subject of this study was to examine the antioxidative activity ...
... These results are suported by the results of Ochoa, Kesseler, De Michelis, Mugridge, and Chav... more ... These results are suported by the results of Ochoa, Kesseler, De Michelis, Mugridge, and Chaves (2001) who reported that in samples kept in the presence of light the concentration of pigments decreases more strongly than in samples kept in the dark. Kucharska et al. ...
The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for thei... more The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for their industrial processing into high-quality juices. Polyphenolic composition analyses (identification and quantification), soluble fraction of procyanidins, antioxidant capacity assays and cluster analysis were measured. A total of 19 kinds of polyphenolic compounds were the following in the juices: before and after 6 month of storage time at 4 and 30°C. Large variations in polyphenolic compounds content were found as affected by quince cultivar. The total phenolics determined by UPLC ranged from 4045 mg to 721 mg/ 100 mL of juices, and was high correlated with antioxidant activity. During 6 months of storage a significant change was observed in the content of polyphenols, especially in procyanidins (37% and 55%, respectively). This result may be useful for the juice industry as a starting point for the development of tasty quince juices with high levels of bioactive compounds.
Flax (Linum usitatissimum L.) is an annual plant cultivated in moderate climates. Although the ge... more Flax (Linum usitatissimum L.) is an annual plant cultivated in moderate climates. Although the genus Linum contains about 230 species, Linum usitatissimum is the only species which fulfills a commercial function, serving as a fiber donor for the textile industry and the production of linseed oil. The flax breeding is often limited due to the decrease in yield caused by fungi infection. The ectopic expression of a potato b-1,3-glucanase cDNA in flax has improved the plant's defence against pathogen. The resistance of transgenic lines against Fusarium oxysporum and Fusarium culmorum was about threefold higher than for the non-transformed plants. In an in vitro experiment the transgenic plant extract inhibited fungi growth and the inhibition was abolished by extract heating and anti-b-glucanase antibody treatment. By further investigation into the molecular basis of transgenic flax resistance, the metabolic profiling of the plant was performed. The significant decrease in the content of carbohydrate, fatty acids and organic acids and the increase in the level of selected amino acids, polyamines and antioxidant were revealed. What is interesting is that the transgenic plants showed a significant decrease in lignin content, which may lead to the improvement of flax fibre retting. q
The aim of this study was to determine selected phytochemicals in berries of eight sea buckthorn ... more The aim of this study was to determine selected phytochemicals in berries of eight sea buckthorn (Hippophae1 1 rhamnoides subsp. mongolica) cultivars, including lipophilic and hydrophilic compounds. In the experiment chromatographic 12 analyses, GC (phytosterols and fatty acids), UPLC-PDA-FL, LC-MS (polyphenols), and HPLC (L-ascorbic acid), as well 13 spectrophotometric method (total carotenoids) were used. The lipid fraction isolated from whole fruit contained 14 phytosterols 14 (major compounds β-sitosterol > 24-methylenecykloartanol > squalene) and 11 fatty acids in the order MUFAs > SFAs > 15 PUFAs. Carotenoids occurred in concentrations between 6.19 and 23.91 mg/100 g fresh weight (fw) (p < 0.05). The major 16 polyphenol group identified in berries was flavonols (mean content of 311.55 mg/100 g fw), with the structures of isorhamnetin 17 (six compounds), quercetin (four compounds), and kaempferol (one compound) glycosides. Examined sea buckthorn cultivars 18 were characterized also by a high content of L-ascorbic acid in a range from 52.86 to 130.97 mg/100 g fw (p < 0.05). 19
Iron-induced oxidation of (+)-catechin in a wine-like solution yielded typical products, includin... more Iron-induced oxidation of (+)-catechin in a wine-like solution yielded typical products, including colourless and yellow compounds. Structural characterization of the major colourless one indicated that it is a dimer, in which flavanol units are linked through a carboxy-methine bridge. Unlike what might be expected, the structure showed that oxidation does not affect catechin directly, but tartaric acid, to give glyoxylic acid, which then reacts with two flavanol units. From a mechanistic point of view, the reaction resembles, once glyoxylic acid is formed, that of acetaldehyde-induced condensation well documented in enology. Thus, an ion series (up to trimer) was detected by mass spectrometry in the model solution. On the other hand, yellow products formed from colourless ones, especially from that isolated, suggests that a second pathway contributing to browning competes with polycondensation reactions. ~, 1997
Compounds contained in fruits and leaves of blackcurrant (Ribes nigrum L.) are known as agents ac... more Compounds contained in fruits and leaves of blackcurrant (Ribes nigrum L.) are known as agents acting preventively and therapeutically on the organism. The HPLC analysis showed they are rich in polyphenol anthocyanins in fruits and flavonoids in leaves, that have antioxidant activity and are beneficial for health. The aim of the research was to determine the effect of blackcurrant fruit and leaf extracts on the physical properties of the erythrocyte membranes and assess their antioxidant properties. The effect of the extracts on osmotic resistance, shape of erythrocytes and hemolytic and antioxidant activity of the extracts were examined with spectrophotometric methods. The FTIR investigation showed that extracts modify the erythrocyte membrane and protect it against free radicals induced by UV radiation. The results show that the extracts do not induce hemolysis and even protect erythrocytes against the harmful action of UVC radiation, while slightly strengthening the membrane and ...
The aim of the study was to determine changes incurred by polyphenolic compounds from selected fr... more The aim of the study was to determine changes incurred by polyphenolic compounds from selected fruits in the lipid phase of the erythrocyte membrane, in liposomes formed of erythrocyte lipids and phosphatidylcholine liposomes. In particular, the effect of extracts from apple, chokeberry, and strawberry on the red blood cell morphology, on packing order in the lipid hydrophilic phase, on fluidity of the hydrophobic phase, as well as on the temperature of phase transition in DPPC liposomes was studied. In the erythrocyte population, the proportions of echinocytes increased due to incorporation of polyphenolic compounds. Fluorimetry with a laurdan probe indicated increased packing density in the hydrophilic phase of the membrane in presence of polyphenolic extracts, the highest effect being observed for the apple extract. Using the fluorescence probes DPH and TMA-DPH, no effect was noted inside the hydrophobic phase of the membrane, as the lipid bilayer fluidity was not modified. The p...
Three flavonoids of pharmaceutical importance-baicalein, baicalin, and wogonoside-were isolated f... more Three flavonoids of pharmaceutical importance-baicalein, baicalin, and wogonoside-were isolated from a Chinese medicinal plant Scutellaria baicalensis Georgi and studied by 13C NMR in solution and solid state. Two-dimensional (2D) NMR spectroscopy in the liquid phase and dipolar dephasing (DD) experiments in magic-angle spinning (MAS) spectra enabled the assignment of 13C resonances. The cross-polarization (CP) time constants T(CH) and relaxation times T(H) (1rho) were obtained from the variable-contact time experiments. The principal elements of the 13C chemical shift tensor were determined in the spectra recorded under slow sample spinning (2 kHz) using phase-adjusted spinning sideband (PASS)-2D NMR technique, and were verified by density functional theory gauge-independent atomic orbital (DFT GIAO) calculations of shielding constants. Analysis of the 13C delta(ii) and comparison with shielding parameters calculated for different conformers of compounds 1-3 enabled the selection of the most reliable geometry in the solid phase. In all three compounds, an intramolecular hydrogen bond C5--OH...=C4 is formed; the existence of baicalein and baicalin with &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;anticlockwise&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; orientation of OH groups is more probable.
The stability of phenolic compounds of three strawberry cultivars was evaluated for changes durin... more The stability of phenolic compounds of three strawberry cultivars was evaluated for changes during prefreezing treatments, storage and various freezing and thawing conditions. Polyphenol content was determined by HPLC-DAD-FL. The sum of assayed polyphenolic (proanthocyanidin and monomeric flavan-3-ols, anthocyanins, ellagic acid, p-coumaric acid) represented 2858.4 mg/kg in Kent, 2893.1 mg/ kg in Elkat, and 2438.0 mg/kg in Senga Sengana. After freezing, 4.5-33.6% of polyphenols were lost; protective effects of prefreezing treatments were seen on anthocyanidins and proanthocyanidins: ascorbic acid was the most effective pretreatment, allowing retention of 3.9-27.5% of anthocyanins, and almost total recovery (3.9-23.9%) when associated with liquid nitrogen freezing. Pectin and sugar only allowed retention of 3.0-25.1% and 5.5-25.4% of the antocyanins, respectively. Thawing of the strawberries in a microwave oven (instead of 20 h at 20 C) had a further positive effect on retention of anthocyanins, proanthocyanins, (þ)-catechin and ellagic acid.
Journal of the Science of Food and Agriculture, 2007
Clear and cloudy apple juices from Idared and Champion varieties were studied for their radicalsc... more Clear and cloudy apple juices from Idared and Champion varieties were studied for their radicalscavenging effects. The polyphenolic content and composition of the juices before and after thiolysis were determined by high-performance liquid chromatography with diode array detection. Cloudy juices, especially that prepared from Champion variety, had a higher content of procyanidins than clear juices. Radical-scavenging activity was measured by electron paramagnetic resonance (EPR) spectroscopy using the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. All juices showed long-lasting radical-scavenging activity, and EPR spectra were recorded over time to follow the reaction kinetics. Scavenging of DPPH showed pseudo-first-order kinetics, which might be expected in the presence of polymerised antioxidants that prevent closer contact between the DPPH radical and hydroxyl groups. The content of polymeric procyanidins showed a linear dependence on the rate constant, suggesting that these compounds are mainly responsible for time-extended radical-scavenging activity. The antioxidant properties of apple juices were much better reproduced by EPR spectroscopy than by UV-visible measurements. The former method is especially sensitive to the concentration of polymerised or bound procyanidins, whilst the latter method requires transparent (clear) samples. Apple juices, especially cloudy ones, are a rich source of natural antioxidants that may be used in the pharmaceutical or food industry.
Flax (Linum usitatissimum L.) is a very important source of natural fibres used by the textile in... more Flax (Linum usitatissimum L.) is a very important source of natural fibres used by the textile industry. Flax fibres are called lignocellulosic, because they contain mainly cellulose (about 70%), with hemicellulose, pectin and lignin. Lignin is a threedimensional polymer with a high molecular weight, and it gives rigidity and mechanical resistance to the fibre and plant. Its presence means the fibres have worse elastic properties than non-lignocellulosic fibres, e.g. cotton fibres, which contain no lignin.
International Journal of Food Science & Technology, 2008
The purpose of the present study was to evaluate the effect of rhubarb juice addition and peeling... more The purpose of the present study was to evaluate the effect of rhubarb juice addition and peeling in apple pure´e production and storage on its phenolic composition, antioxidant activity and colour. The apple material used in this study was of two varieties: Sampion and Idared. The apple pure´es prepared in three variants (control pure´es, peeling pure´es and pure´es with 5% of rhubarb juice) were stored for 3 and 6 months at 30°C. Apple pure´es were investigated for their antioxidant activity, change of colour and contents of phenolic compounds plus the polymer procyanidins and degree of polymerization (DP). The preparation of pure´es from apples without peeling and the addition of rhubarb juice during pure´e preparation had significant influence on polyphenol content. The pure´e prepared from peeled apples of Idared variety had phenolic content 2.2 times lower than the control sample (non-peeled apples). The highest level of total polyphenols was found in Idared + rhubarb sample (129.82 mg 100 g )1 pure´e). The content of this compound in Idared control sample was more than 2.8 times lower than in Idared pure´es with rhubarb. The use of non-peeled Idared apples and 5% of rhubarb juice in pure´e preparation significantly increased polymeric procyanidins from 11.68 to 75.20 mg 100 g )1 and other phenolics from 9.23 to 54.62 mg ⁄ 100 g. This effect for Sampion apples was smaller. The procyanidins during pure´es storage were more stable in samples with rhubarb juice addition. The pure´e samples with the addition of rhubarb juice had higher antioxidant activity measured using ABTS (2,2¢azinobis-(3-ethylbenzthiazoline-6-sulphonic acid)) than pure´e samples without the addition (two times higher for Idared variety) of rhubarb juice. After 3 and 6 months of storage at temperature 30°C, the antioxidant capacity decreased in all pure´es. Rhubarb juice had only high and positive effect on L* value in the case of Idared variety. The results showed that all Sampion apple pure´es had higher L* values than Idared.
In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids w... more In two experiments, the response of rats to feeding with diets containing grapefruit flavonoids was examined. In the first experiment, during 8 weeks, four diets without or with 0.1, 0.2 and 0.4% extract of flavonoid from grapefruit (from 0.05 to 0.2% DM pure flavonoids) were applied. In the second experiment, during 10 days, diets with oxidised fat (100 meq O 2 /kg) and without or with 0.4% extract of flavonoid were applied. The obtained results showed that the addition of 0.1-0.4% extract of flavonoid from grapefruit did not affect the diet intake and the body weight gain of rats, and slightly increased the antioxidative potential of serum (decreased the MDA content but had no significant effect on the PGx and SOD activities). The addition strongly affected functioning of the blind gut ecosystem causing an increased filling with contents, an increase in the intestinal wall mass and pH, as well as a decrease in the microbiological activity of b-glucuronidase and an increase in the a-galactosidase activity. #
In experiments on rats, five diets without or supplemented with polyphenol extracts from differen... more In experiments on rats, five diets without or supplemented with polyphenol extracts from different sources (flavons from skullcap, catechins from green tea, anthocyanins from chokeberry and condensed tannins from faba bean) were applied. Obtained results suggested that when catechin extracts were added to the diets in large amounts (0.8%), beneficial effects (reduction of total cholesterol and LDL fraction in serum) were observed, but also reduction in protein digestibility and protein efficiency ratio (from 94.6 to 93.1% and from 2.57 to 2.40, respectively), compared to the control group. All extracts decreased the activity of erythrocyte superoxide dismutase and increased the activity of alanine aminotransferase in the serum. Only the tannin extract decreased the content of calcium in femur. More profitable biological properties were found for catechin extract from green tea and flavons extract from skullcap, compared to anthocyanins from chokeberry and condensed tannins from faba bean. #
Effects of pomace maceration on yield, turbidity, cloud stability, composition of phenolics, anti... more Effects of pomace maceration on yield, turbidity, cloud stability, composition of phenolics, antioxidant activity and colour properties were studied, to evaluate the potential applicability of enzyme preparations in puree-enriched cloudy apple juice production. The yield of mixed juice and puree from pomace obtained in the enzymatic processing of apple ranged from 92.3% to 95.3%, significantly higher than the yield from the control without enzymatic pomace treatment (81.8%). Higher turbidity was obtained upon pomace treatment with Pectinex XXL and Pectinex Ultra SPL enzymes. The total content of phenolic compounds in apple pomace was higher than in raw juices (1520 mg/kg and 441 mg/L, respectively). The total polyphenol yields were higher in juices treated with Pectinex AFP L-4, Pectinex Yield Mash and Pectinex XXL, as compared to the control treatment. During 6 months of storage, a significant change was observed in the content of polyphenols, especially in procyanidin fractions.
The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chloroge... more The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chlorogenic acid was the most abundant acid (20.0 mg/100 g in microwaved Idared); other polyphenols identified in high concentrations included (À)-epicatechin, procyanidin B1 and B2; quercetin and cyanidin glycosides were found in minor concentrations. The Shampion purées had higher total phenolics (142 mg/100 g) and procyanidin B2 concentrations (17.3 mg/100 g) than the Idared ones, and polymeric procyanidins represented 41% of all polyphenols. Antioxidant capacities of the samples, determined by spectrophotometric methods and EPR spectroscopy, correlated well with the concentration of polyphenols. The antioxidant properties could be better represented by EPR than by UV-vis measurements. The latter require transparent (clear) samples whereas EPR can be a method of choice in the assessment of radical-scavenging activity of dense and cloudy apple purées. Our results support the putative high antioxidant value of apple purées and define their capacity in terms of the major constituents. Apple purées are a rich source of natural antioxidants, especially of chlorogenic acid and procyanidins.
Polyphenols were analyzed by HPLC after thioacidolysis of proanthocyanidins polymers and acid hyd... more Polyphenols were analyzed by HPLC after thioacidolysis of proanthocyanidins polymers and acid hydrolysis of phenolic acid esters. The predominant constitutive units of the procyanidins of Aruncus Silvester and Potentilla alba roots were (−) epicatechin, and ...
The significance of antioxidants in preventive medicine is well known. Increasing interest has be... more The significance of antioxidants in preventive medicine is well known. Increasing interest has been devoted to naturally occurring compounds–polyphenols–because of their beneficial health effects. The subject of this study was to examine the antioxidative activity ...
... These results are suported by the results of Ochoa, Kesseler, De Michelis, Mugridge, and Chav... more ... These results are suported by the results of Ochoa, Kesseler, De Michelis, Mugridge, and Chaves (2001) who reported that in samples kept in the presence of light the concentration of pigments decreases more strongly than in samples kept in the dark. Kucharska et al. ...
The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for thei... more The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for their industrial processing into high-quality juices. Polyphenolic composition analyses (identification and quantification), soluble fraction of procyanidins, antioxidant capacity assays and cluster analysis were measured. A total of 19 kinds of polyphenolic compounds were the following in the juices: before and after 6 month of storage time at 4 and 30°C. Large variations in polyphenolic compounds content were found as affected by quince cultivar. The total phenolics determined by UPLC ranged from 4045 mg to 721 mg/ 100 mL of juices, and was high correlated with antioxidant activity. During 6 months of storage a significant change was observed in the content of polyphenols, especially in procyanidins (37% and 55%, respectively). This result may be useful for the juice industry as a starting point for the development of tasty quince juices with high levels of bioactive compounds.
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Papers by Jan Oszmiański