Peter Czako

Evaluation of carotenoids, polyphenols content and antioxidant activity in the sea buckthorn fruit

Normal 0 false false false SK X-NONE X-NONE Due to the content of biologically active substances, sea buckthorn ( Hippophae rhamnoides L.) has become the object of great interest of both, experts and the general public. It is appreciated particularly for the high content of vitamins and other biologically active substances, not only in berries but also in leaves and bark. The aim of the study was to evaluate the nutritional quality of sea buckthorn juice prepared from different varieties of sea buckthorn based on the content of total carotenoids, polyphenols and antioxidant activity. In this study we used varieties Hergo, Tytti, Vitaminaja, Raisa, Askola, Dorana, Slovan, Leikora, Bojan, Terhi and Maslicnaja. Content of different components was quantified using spectrophotometry. The total carotenoids content expressed as β-carotene content in juice ranged from 50.63 mg.100 g -1 DM to 93.63 mg.100 g -1 DM, the highest content was in variety Askola and the lowest one in Terhi. Total polyphenols content determined by Folin-Ciocalteu method ranged from 13.03 mg GAE. dm -3 DM to 25.35 mg GAE. dm -3 DM. The highest content was identified in juice of variety Dorana and the lowest one in Raisa. The antioxidant activity quantified by the FOMO method ranges from 45.11 g AA. dm -3 DM to 108.77 g AA. dm -3 DM. The highest antioxidant activity was determined in juice of Dorana and the lowest in variety Bojan

Effect of drying temperature on lycopene content of processed tomatoes.

Recently it has been increasing interest worldwide in the production of dehydrated tomato products, which are used in food industry and in pharmacy. An important indicator of the quality of products, beside the microbiological stability is health safety and lycopene content. The aim of this work was to evaluate the effect of drying temperature on changes of the content of lycopene in selected varieties of tomato. Drying was performed at 45 °C, 70 °C and 90 °C. Varieties of Darina F1, Denar, Kecskemety, Orange, Paulina F1, Sejk F1 were used. Tomatoes were processed into dried slices with the dry matter content of 80-85%. Content of lycopene was determined spectrophotometrically. The content of lycopene in fresh tomatoes ranged from 63.378 mg 100 g -1 of dry matter (Orange) to 302.37 mg 100 g -1 of dry matter (Sejk F1). After drying at all temperatures, content of lycopene decreased on average of 64.48 to 68.3%. The most significant changes were found at temperature of 90 °C. Based on the results the most appropriate temperature for drying among the monitored temperatures was at 70 °C, in this case the content of lycopene in the product ranged from 12.839 mg 100 g -1 dry matter (Orange) to 115.9 mg 100 g -1 of dry matter.

Sauvignon wine quality as affected by its processing and storage

The colour and limpidity are the first sensory attributes of wines that are appreciated by consumers, predisposing their acceptance or rejection. The aim of this work was to monitor the effect of harvest, processing (different clarification and treatment of must) and storage on the quality of Sauvignon wine. The wines were stored for two years in the wine cellar at 12°C and 70 % of humidity, in the bottles. The acid content, residual sugar and alcohol content among chemical parameters and sensory profile of wines were observed. Sensory quality of wines was evaluated by the aromatic profile (profile method). Based on acquired results, two years of wine storage significantly affected the total acid content of wines and alcohol content. Different treatments of must affected residual sugars, the variant with the maximum dose of the clarification preparation (highly pure cellulose, polyvinylpolypyrrolidone, gelatin and mineral adsorbents) showed statistically the highest content of residual sugars. From the sensory point of view, sensory profiles of wines were different compared to the first and second harvest of grape, sensory profiles of wines were changed also after two years of storage. The fourth variant appeared to be the best stable, treated with the addition of clarification preparation at the dose of 30 g. 100 L-1 must. Because from the same variety Sauvignon were produced wines of different chemical and sensory qualities, some gastronomy recommendations were done as well.

The effect of UV-C irradiation on grape juice turbidity, sensoric properties and microbial count

In this work, we investigated the effect of UV-C radiation (254 nm) on turbidity, microbial count and sensoric properties of the grape juices treated or not treated with sulphur dioxide. The UV-C radiation is considered to be germicidal against microorganisms. This technology is routinely used to treat drinking water. Application of this method for the purpose of treating the wine was tested in few studies. These studies have shown a positive effect on the inactivation of microorganisms, but they not dealt in detail with the sensory properties of grape juice after the treatment. The main idea of using this method appears to eliminate the sulphur dioxide from wine making technology. There are people who have a genuine allergy to sulfites, and these allergies are often linked with asthma. These people have an rapid onset of symptoms when drinking liquids like wine treated with sulphur dioxide. In our work we have found that the application of this method of treating the grape juice is problematic. Intensity of UV-C radiation increases the turbidity of grape juices. This effect was observed in all grape juices with or without addition of sulphur dioxide and also in clarified or not clarified grape juices. We found that UV-C radiation negatively affect the sensory properties of grape juices. This effect was more pronounced in grape juices treated with SO2. The smell and taste were significantly negatively changed. Exposure of grape juice treated with sulphur dioxide to UV-C radiation can probably lead to arising the sulphur compounds, which affects the smell and taste of grape juices. Also, it is very likely that the negative change in taste and smell may affect the quality of produced wines. For this purpose, we do not recommend to use UV-C treatment for the grape juice treatment. It will be interesting to conduct a detailed analysis of the grape juices composition before and after UV-C radiation treatment.

Effect of grape seed extract on quality of raw-cooked meat products

In the present study we aimed to evaluate the oxidative stability of Spis frankfurters after application of grape seeds extracts (Blauburger + Cabernet Sauvignon and Danube) in amount of 10 mL.kg -1 during 12 days of their storage at 4 °C. Sensory evaluation of Spis frankfurters was carried out after 4 days of storage by 6-point ranking system (Surface appearance and color, appearance and color when cut, texture, aroma and flavor). It was found that sensory quality of Spis frankfurters was not significantly ( p >0.05) affected by application of grape seed extracts. Oxidation stability of Spis frankfurters after 12 days of storage at 4 °C was positively influenced ( p ≤0.05) only in the group with addition of extract made from grape seed Blauburger +Cabernet Sauvignon. This may probably related with the higher antioxidant activity of extract of this variety (100.5%) compared to an extract made from grape seed variety of Danube (55.8%). Also, it was not found significant differences ( p >0.05) of antioxidant activity between extract made from grape seeds variety Danube compared with the control group. Normal 0 21 false false false SK X-NONE X-NONE

Quality assessment of juice prepared from different varieties of currant (Ribes L.)

In the Slovak Republic currants are traditionally grown species of small fruits mainly in house gardens. Although currently their area is very small compared to the other types of fruit. We can see the importance of growing this genus ( Ribes L.) in its good adaptability to climate conditions, in small growing demands and in stable production of nutritionally highly valuable fruit. Currant berries as well as fresh currant juice are characterized by the presence of whole complex of antioxidant active substances. The aim of this study was to evaluate the nutritional quality of currant juice prepared from various species and varieties of genus Ribes (L.). based on the content of their total polyphenols, anthocyanin dyes and antioxidant activity. In work we used varieties Blanka, Primus, Viktoria, Heinemannova neskora, Red Lake, Treny, Jonkheer van Tets, Fertodi, Titania, Triton and Ojebyn. Contents of evaluated components were assessed spectrophotometrically. Total polyphenol content of monitored samples determined by the Folin-Ciocalteu method reached values from 1897.43 mg GAE.dm -3 DM to 3712.21 mg GAE.dm -3 DM. The highest one was in juice from variety Primus and the lowest from variety Blanka. In white varieties of currant, the presence of anthocyanin dyes was immeasurable. In varieties of red and black currant anthocyanin dye content achieved values from 1947.64 mg.dm -3 DM (Jonkheer van Tets) to 4161.07 mg.dm -3 DM (Heinemannova neskora). The antioxidant activity determined by the FOMO method reached values from 4130.42 mg AA.dm -3 DM to 6571.69 mg AA.dm -3 DM. We recorded the highest antioxidant activity in juice of variety Fertodi and the lowest of variety Primus.