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- Author or Editor: É. Stefanovits-Bányai x
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The water-soluble carbohydrates contributing to the response of wheat seedlings to cadmium stress in nutrient solution were studied with or without Ti(IV)-ascorbate supply. The total water-soluble carbohydrate, glucose, fructose, sucrose, glucan and fructan contents, and the cadmium and titanium contents were measured in wheat seedlings exposed to 10-4 M Cd or 10-5M Cd with either Ti(IV)-ascorbate or Na-ascorbate in the medium. Glucose, fructose and fructan showed the greatest response to Cd, ascorbate and titanium treatments. The sugar content in plants exposed to Cd increased with the metal concentration. Titanium tended to decrease the cadmium-induced sugar accumulation. Ti(IV)-ascorbate and Na-ascorbate were also applied without Cd to study the effect of these chemicals. In general, Na-ascorbate induced a higher accumulation of sugar components than Ti(IV)-ascorbate. Titanium addition in Cd-containing solution caused a significant decrease in the cadmium accumulation in the leaves. An increase in titanium content was observed only in the roots, higher values being measured in plants grown in solution containing 10-4 M Cd.
In the past decades many papers were published on the nutritional effect and bioactive components of edible mushrooms. The fungi are able to accumulate secondary metabolites, for example, phenolic compounds, polyketides, terpenes and steroids. In case of mushrooms the button mushrooms are preferred in the Eastern-European region. Therefore white and cream type button mushroom (Agaricus bisporus) and different A. subrufescens (syn. A. blazei) cultivars were cropped, total phenolic content and antioxidant capacity (FRAP) were measured in two years of experiments. To develop the description method of mushroom products, software-supported profile analysis was applied to characterize them. The aim of the research was to compare the sensory profiles of the samples, and to find those characteristics, they actually differ in.
Fruits and vegetables are increasingly consumed as a part of healthy diets. They are routinely consumed raw, without any further antimicrobial processing. The aim of our studies was to determine radiation doses improving the microbial safety of fruits without diminishing quality parameters of these produce. Effects of low dose irradiation on the microbiota, antioxidant capacity, total polyphenol contents, firmness and sensory properties of pre-cut apple, orange and banana were investigated. Dose of 2.0 kGy was able to reduce considerably the microbiological contamination of fruits, apple, orange, banana, but microorganisms surviving the irradiation are able to recover and grow during refrigerated storage. Two kGy was an acceptable radiation dose for the treatment of these products, having no significant effect on the mentioned quality parameters.
Vitamins form a heterogeneous chemical group having different stability. In foodstuffs some of them might be bound to matrix components. In the case of vitamin supplemented food products, since the vitamins are not strongly embedded in the matrix a general extraction method could be fit for purpose. The aim of this study was the simultaneous determination of the most common water-soluble vitamins, i.e. ascorbic acid (C), riboflavin (B 2 ), niacin (B 3 ), pyridoxine (B 6 ), folic acid (B 9 ) in enriched food products. Sample preparation based on the European Standard (CEN, 2003) was optimised for further LC-MS compatible chromatography. The separation of the vitamins was achieved by reversed-phase liquid chromatography. Detection was carried out with a photodiode array detector at four different wavelengths. The chromatographic method and the sample preparation were successfully applied for vitamin-enriched cereal, instant cacao powder and fruit juice samples.
Total phenolic content and antioxidant capacity (FRAP method) of Ginkgo biloba L. leaves and of different commercial ginkgo teas were determined and compared. Different water extracts (infusions and decoctions) were prepared varying the time of infusing, boiling, and steeping, and also aqueous ethanolic (water/ethanol 80/20 v/v) extract was made.
Total phenolic contents and FRAP values of collected ginkgo leaves were similar to those of commercial ginkgo mono teas, while these parameters were significantly higher for ginkgo teas containing ginseng or green tea. Decoction was more effective than infusion for extracting antioxidative compounds, in contradiction to suggested preparation methods by the producers. Aqueous ethanolic extracts had significantly higher total phenolic content and antioxidant capacity than water extracts. The correlation between phenolic content and FRAP values was very strong and positive for water extracts of collected leaves, while it was weak and negative for the tea products.
Of the twenty table beet ( Beta vulgaris L. ssp. esculenta convar. crassa provar. conditiva ALEF.) cultivars investigated for several nutritionally important components (betaine, betanin, phenol, glucose, fructose, sucrose) formerly (Hájos et al., 2004), cultivar Ditroit having average quality parameters was chosen for in vitro animal experiments. The hyperlipidemic rat model is suitable to study the physiological effect of table beet on the metabolic alterations and the redox homeostasis in the liver. In fatty liver, as a consequence of hyperlipidemy, the redox homeostasis is strongly injured. General biologically active compounds of table beet have indirect lipid lowering effect and antioxidant properties. Therefore, the effect of lyophilised table beet powder was studied on altered lipid metabolism and redox parameters in hyperlipidemic rats. Hyperlipidemy was induced by a fat-rich diet, and both in the control group and in the hyperlipidemic group, animals were treated with the lyophilised table beet powder (2 g bwkg −1 ) added into rat chow for 10 days parallel with the feeding. Significant antioxidant activity of table beet was recorded in the hyperlipidemic liver. This phenomenon was expected because of the significant amount of betanin and the high total polyphenol content of the beet. Significant beneficial changes were also observed in the serum cholesterol level, alkaline phosphatase and alanine-aminotransferase activities, although a non-expected elevation was observed in the serum bilirubin level in hyperlipidemy. Non-specific H-donor activity was not changed, but protein related free SH-group concentration was decreased in the plasma. Serum triglyceride level was better after table beet treatment in normolipidemy, only. Change of redox-homeostasis was more favourable in the liver during the treatment. Diene conjugate content and the level of induced free radicals decreased during the table beet treatment in case of fatty liver. These changes were due to the bioactive components of the commercially available table beet. Consequently, table beet due to its specific qualities beneficially influences several metabolic pathways, therefore it can be considered as a functional food.
Dietary intake of polyphenols and vitamins before surgery may have beneficial effect on survival of the patients. Table beet (Beta vulgaris L. var. rubra) contains bioactive agents, which have a wide range of different physiologic effects. These agents have beneficial antioxidant properties. The aim in the present study was to determine the gut protecting properties of bioactive substances of table beet in a model of ischaemic-reperfusion injury of the rat liver. Chemiluminescent intensity, H-donating ability, reducing power and free SH-group concentracion were determined by luminometry and spectrophotometry in duodenum and plasma. Lyophilized table beet increased significantly the free radical scavenging property of the plasma measured by chemiluminometry. Other antioxidant parameters of the plasma increased in rats fed table beet diet, and change in reducing power was significant. Beneficial effect of the treatment was found in changes of total scavenger capacity of the duodenum during ischaemia-reperfusion injury. H-donating ability and reducing power of the gut decreased in the table beet-fed group during ischaemia-reperfusion compared to normal group with ischaemia-reperfusion. Based on these data, it can be concluded that table beet can protect the entire body from the oxidative damage caused by ischaemia-reperfusion of the liver, but the effect of table beet treatment on gut mucosa needs further investigation.
Different osmotic agents (OA), such as potassium acetate (CH3COOK), potassium carbonate (K2CO3) and ammonium nitrate (NH4NO3), have been examined as alternatives to the traditionally used calcium chloride (CaCl2) for osmotic distillation concentrating of clarified and pre-concentrated sour cherry (Prunus cerasus L.) juice. Comparison of the process performances based on the permeate fluxes has been carried out. Regarding the permeate flux results, simplified estimation of the overall mass transfer coefficient of the most effective osmotic agent and the reference (CaCl2) solution has been also performed. Furthermore, analytical methods such as total antioxidant activity (TAA) and total polyphenolic content (TPC) using spectrophotometric assays have been also carried out to evaluate the effect of the osmotic distillation on the valuable compounds content of concentrated sour cherry juice. CH3COOK was found to be the most effective, resulted more than 25% higher permeate flux during the sour cherry juice concentration. K2CO3 and NH4NO3 were less effective. The simplified mass transfer estimation showed that the CH3COOK is more effective only at near saturated concentrations compared to the CaCl2. Regarding the TAA and TPC contents, a significant loss was found in case of all OAs during the concentration procedures.
