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The antioxidant activity of selected species of small fruit
Křenová, Alena ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.
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Comparison of an analytical techniques for determination of an antioxidant activity in food
Křenová, Alena ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This bachelor‘s thesis deals with the characterization of natural and synthetic antioxidants and their effects on free radicals. Natural antioxidants are usually absorbed as a part of complex mixtures and that’s why we try to characterize an antioxidant activity as a whole. Chemical and physical methods have been developed to determine the total antioxidant activity of food. This thesis focuses on chemical methods, specifically on ABTS and DPPH, which are based on a reaction of antioxidants with synthetic radicals. Next chemical method is FRAP, which is based on the reducing ability of antioxidants. In the experimental part, these methods are compared from a perspective of their performance and the results of the analysis of real food samples.
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Antioxidative parameters of fruit model product.
KRATOCHVÍLOVÁ, Lenka
The content of the main components (anthocyanins, quercetin, chlorogenic acid, L-ascorbic acid, rutin, total polyphenols) was determined in the syrup of elderberries (Sambucus nigra L.) by spectrophotometry or high-performanceliquid chromatography. Furthermore, the antioxidant activity of this syrup was determined using three methods: ABTS, FRAP, and DPPH. The measurement results were statistically processed and compared using correlation analysis, specifically using the Pearson correlation coefficient. It was found that the prepared product contains 2160 mg/kg anthocyanins, 201 mg/kg rutin, 26 mg/kg chlorogenic acid and 679 mg/l polyphenols. No free quercetin was found. The content of L-ascorbic acid in the original elderberries was relatively low and therefore for study purposes, the syrup was enriched with this substance in the amount of 0.5% (w/w) to study the connection of its content with other substances. It is clear from the statistical processing that the concentration of chlorogenic acid correlates with the antioxidant activity measured by the FRAP method and the concentration of polyphenols to the antioxidant activity measured by the DPPH method.
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Sledování antioxidační aktivity u laboratorního potkana při zkrmování barevné pšenice Konini
Holeksová, Veronika
In the experiment, we observed how it affects feeding colored wheat grains with purple color on the antioxidant activity in the liver and in the blood of rats. For the experiment, we used 64 male rats Wistar albino four to six weeks. The experiment was performed four weeks. Experimental group (n=32) rats fed the only color wheat Konini. Purple wheat Konini (14.01 mg/g of anthocyanins). The control group (n=32) are fed conventional wheat Bohemia mixed with gluten to supplement the crude protein content as Konina (16%). During the experiment, we looked at three day intervals additions and weighed daily feed consumption. Antioxidant activity was measured by methods DPPH, FR, FRAP and ABTS. Results of measurement of antioxidant activity in the liver appeared inconclusive for all the methods. Only the results of the FR and FRAP with blood appeared conclusive. At control FR mg/l 297,35+-23,94 and Konini 215,57+-12.16 .FRAP mg/l control 28,78+-1,35 and 23.86 +-1.28 Konin. Other methods for blood came out inconclusive as well as in the liver. We found that liver weight in rats fed wheat Konin was 7% lower than in control rats. The results were processed using a statistical method ANOVA Scheffe test.
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The antioxidant activity of selected species of small fruit
Křenová, Alena ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.
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Comparison of an analytical techniques for determination of an antioxidant activity in food
Křenová, Alena ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This bachelor‘s thesis deals with the characterization of natural and synthetic antioxidants and their effects on free radicals. Natural antioxidants are usually absorbed as a part of complex mixtures and that’s why we try to characterize an antioxidant activity as a whole. Chemical and physical methods have been developed to determine the total antioxidant activity of food. This thesis focuses on chemical methods, specifically on ABTS and DPPH, which are based on a reaction of antioxidants with synthetic radicals. Next chemical method is FRAP, which is based on the reducing ability of antioxidants. In the experimental part, these methods are compared from a perspective of their performance and the results of the analysis of real food samples.
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Stanovení antioxidačního statusu u potkanů při zkrmování pšenice Citrus
Bendová, Kateřina
This thesis examines the influence of wheat Citrus with higher content of lutein in comparison with common wheat on antioxidant activity of the rat blood plasma and liver tissue. In the experiment, 32 male rats of Wistar strain were used. The influence of the feeding of yellow wheat varieties Citrus on antioxidant activity was measured in the blood and liver tissue. The experimental group (N = 16) was fed with dried granules of 100% wheat meal from Citrus. The control group (N = 16) was fed with similar feed prepared from two common wheat. Content of crude protein was the same in the both group. Body weight gain were followed in three-day intervals and feed consumption was followed daily. Antioxidant activity was measured by DPPH, FR, FRAP and ABTS methods. Values are expressed in gallic acid equivalent. In the blood significant differences (P < 0.05) of antioxidant activity was determined only by ABTS method between "Citrus" group (405.51 +- 7.64 mg /ml) in comparison to "Control" group (479.99 +- 22.54 mg/ml) in contrary to expectation this value of control group was of 18% higher. Values of other antioxidant methods were not significant. In the liver tissue only average value of ABTS method was little higher in Citrus group (409,439 +-13,626) in comparison with control group (389,493 +- 9,271 mg/ml). Similar situation was with DPPH method (20.711 +- 0.867 in Citrus group and 20.037 +- 1.109 mg/ml in the Control group) and difference was also not significant (P> 0.05).
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