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Aalt Bast - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Antioxidant Capacity in blood.
Clinical chemistry and laboratory medicine, 2005Co-Authors: Marc A. J. G. Fischer, Aalt Bast, Theo J. M. Gransier, Lenie M. G. Beckers, Otto Bekers, Guido R.m.m. HaenenAbstract:BACKGROUND: A vast amount of scientific research is directed towards the beneficial effects of Antioxidants on health. For this reason, several assays have been developed to determine the total Antioxidant Capacity of blood. METHODS: In this study two procedures based on the use of the green-blue 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS(*+)) were compared. In the first (commercially available) procedure, ABTS(*+) was generated in the presence of the blood sample. In the second procedure, referred to as the decolorization assay, Antioxidants react with preformed ABTS(*+). RESULTS: It was found that the first procedure leads to greater underestimation of the actual Antioxidant Capacity and is more prone to artifacts than the second procedure. Therefore, only the latter procedure was evaluated in detail and it appeared that (i) plasma is preferred over serum, (ii) the high background produced by albumin can be circumvented by deproteination, (iii) samples can be stored at -80 degrees C for 12 months, and (iv) the assay has high precision. Due to poor linearity, the procedure has to be standardized to allow sample comparison. CONCLUSIONS: The decolorization assay is a reliable and robust assay that can be applied routinely to predict the Antioxidant Capacity of blood.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Interactions between flavonoids and proteins: effect on the total Antioxidant Capacity.
Journal of agricultural and food chemistry, 2002Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Lonneke C. Wilms, Sasja A J N Beetstra, Chantal G.m Heijnen, Aalt BastAbstract:Flavonoids are potent Antioxidants. It is also known that flavonoids bind to proteins. The effect of the interaction between tea flavonoids and proteins on the Antioxidant Capacity was examined. Their separate and combined Antioxidant capacities were measured with the Trolox equivalent Antioxidant Capacity (TEAC) assay. It was observed that the Antioxidant Capacity of several components of green and black tea with α-, β-, and κ-casein or albumin is not additive; that is, a part of the total Antioxidant Capacity is masked by the interaction. This masking depends on both the protein and the flavonoid used. Components in green and black tea, which show the highest masking in combination with β-casein, are epigallocatechin gallate and gallic acid. The results demonstrate that the matrix influences the efficacy of an Antioxidant. Keywords: Antioxidant Capacity; tea; flavonoids; casein; albumin; catechin
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Masking of Antioxidant Capacity by the interaction of flavonoids with protein.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2001Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The effect of Antioxidants is often executed in complex biological mixtures where various interactions may take place. Therefore, the Antioxidant Capacity of Antioxidants in blood plasma is examined. The assay used is the trolox equivalent Antioxidant Capacity (TEAC). This method gives the Antioxidant Capacity of a compound by measuring spectrophotometrically the disappearance of the blue/green stable ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical, caused by scavenging. The results show that the Antioxidant Capacity of quercetin, rutin, catechin or 7-monohydroxyethylrutoside (monoHER) and blood plasma is not additive. This is partly due to interactions between the Antioxidant and plasma proteins. However, the Antioxidant Capacity of α-tocopherol, which also binds to protein, is not affected by the interaction. This means that besides the Antioxidant Capacity of the compound itself, the environment in which the Antioxidant has to execute his function is important.
Guido R.m.m. Haenen - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Antioxidant Capacity in blood.
Clinical chemistry and laboratory medicine, 2005Co-Authors: Marc A. J. G. Fischer, Aalt Bast, Theo J. M. Gransier, Lenie M. G. Beckers, Otto Bekers, Guido R.m.m. HaenenAbstract:BACKGROUND: A vast amount of scientific research is directed towards the beneficial effects of Antioxidants on health. For this reason, several assays have been developed to determine the total Antioxidant Capacity of blood. METHODS: In this study two procedures based on the use of the green-blue 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS(*+)) were compared. In the first (commercially available) procedure, ABTS(*+) was generated in the presence of the blood sample. In the second procedure, referred to as the decolorization assay, Antioxidants react with preformed ABTS(*+). RESULTS: It was found that the first procedure leads to greater underestimation of the actual Antioxidant Capacity and is more prone to artifacts than the second procedure. Therefore, only the latter procedure was evaluated in detail and it appeared that (i) plasma is preferred over serum, (ii) the high background produced by albumin can be circumvented by deproteination, (iii) samples can be stored at -80 degrees C for 12 months, and (iv) the assay has high precision. Due to poor linearity, the procedure has to be standardized to allow sample comparison. CONCLUSIONS: The decolorization assay is a reliable and robust assay that can be applied routinely to predict the Antioxidant Capacity of blood.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Interactions between flavonoids and proteins: effect on the total Antioxidant Capacity.
Journal of agricultural and food chemistry, 2002Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Lonneke C. Wilms, Sasja A J N Beetstra, Chantal G.m Heijnen, Aalt BastAbstract:Flavonoids are potent Antioxidants. It is also known that flavonoids bind to proteins. The effect of the interaction between tea flavonoids and proteins on the Antioxidant Capacity was examined. Their separate and combined Antioxidant capacities were measured with the Trolox equivalent Antioxidant Capacity (TEAC) assay. It was observed that the Antioxidant Capacity of several components of green and black tea with α-, β-, and κ-casein or albumin is not additive; that is, a part of the total Antioxidant Capacity is masked by the interaction. This masking depends on both the protein and the flavonoid used. Components in green and black tea, which show the highest masking in combination with β-casein, are epigallocatechin gallate and gallic acid. The results demonstrate that the matrix influences the efficacy of an Antioxidant. Keywords: Antioxidant Capacity; tea; flavonoids; casein; albumin; catechin
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Masking of Antioxidant Capacity by the interaction of flavonoids with protein.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2001Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The effect of Antioxidants is often executed in complex biological mixtures where various interactions may take place. Therefore, the Antioxidant Capacity of Antioxidants in blood plasma is examined. The assay used is the trolox equivalent Antioxidant Capacity (TEAC). This method gives the Antioxidant Capacity of a compound by measuring spectrophotometrically the disappearance of the blue/green stable ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical, caused by scavenging. The results show that the Antioxidant Capacity of quercetin, rutin, catechin or 7-monohydroxyethylrutoside (monoHER) and blood plasma is not additive. This is partly due to interactions between the Antioxidant and plasma proteins. However, the Antioxidant Capacity of α-tocopherol, which also binds to protein, is not affected by the interaction. This means that besides the Antioxidant Capacity of the compound itself, the environment in which the Antioxidant has to execute his function is important.
Marie-josé S. J. Arts - One of the best experts on this subject based on the ideXlab platform.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
H P Voss - One of the best experts on this subject based on the ideXlab platform.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Antioxidant Capacity of reaction products limits the applicability of the trolox equivalent Antioxidant Capacity teac assay
Food and Chemical Toxicology, 2004Co-Authors: Marie-josé S. J. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The Trolox Equivalent Antioxidant Capacity (TEAC) assay is based on the scavenging of the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS • ) converting it into a colorless product. The degree of decolorization induced by a compound is related to that induced by trolox, giving the TEAC value. The assay is frequently used for constructing structure activity relationships (SARs). HPLC analysis of the reaction mixture, obtained after scavenging of ABTS • by the flavonoid chrysin, shows that a product is formed that also reacts with ABTS • . The product has a higher Antioxidant Capacity and reacts faster with ABTS • than the parent compound, chrysin. In contrast to the reaction product of chrysin, the reaction product of trolox, which is formed during scavenging of ABTS • , i.e. trolox quinone, does not react with ABTS • . The experiments show that the TEAC is the Antioxidant Capacity of the parent compound plus the potential Antioxidant Capacity of the reaction product(s). This means that the TEAC assay does not necessarily reflect the Antioxidant effect of only one structure. This hampers the applicability of the assay for the construction of SARs and for ranking Antioxidants.
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Interactions between flavonoids and proteins: effect on the total Antioxidant Capacity.
Journal of agricultural and food chemistry, 2002Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Lonneke C. Wilms, Sasja A J N Beetstra, Chantal G.m Heijnen, Aalt BastAbstract:Flavonoids are potent Antioxidants. It is also known that flavonoids bind to proteins. The effect of the interaction between tea flavonoids and proteins on the Antioxidant Capacity was examined. Their separate and combined Antioxidant capacities were measured with the Trolox equivalent Antioxidant Capacity (TEAC) assay. It was observed that the Antioxidant Capacity of several components of green and black tea with α-, β-, and κ-casein or albumin is not additive; that is, a part of the total Antioxidant Capacity is masked by the interaction. This masking depends on both the protein and the flavonoid used. Components in green and black tea, which show the highest masking in combination with β-casein, are epigallocatechin gallate and gallic acid. The results demonstrate that the matrix influences the efficacy of an Antioxidant. Keywords: Antioxidant Capacity; tea; flavonoids; casein; albumin; catechin
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Masking of Antioxidant Capacity by the interaction of flavonoids with protein.
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2001Co-Authors: Mariken J.t.j. Arts, H P Voss, Guido R.m.m. Haenen, Aalt BastAbstract:Abstract The effect of Antioxidants is often executed in complex biological mixtures where various interactions may take place. Therefore, the Antioxidant Capacity of Antioxidants in blood plasma is examined. The assay used is the trolox equivalent Antioxidant Capacity (TEAC). This method gives the Antioxidant Capacity of a compound by measuring spectrophotometrically the disappearance of the blue/green stable ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical, caused by scavenging. The results show that the Antioxidant Capacity of quercetin, rutin, catechin or 7-monohydroxyethylrutoside (monoHER) and blood plasma is not additive. This is partly due to interactions between the Antioxidant and plasma proteins. However, the Antioxidant Capacity of α-tocopherol, which also binds to protein, is not affected by the interaction. This means that besides the Antioxidant Capacity of the compound itself, the environment in which the Antioxidant has to execute his function is important.
Ronald L. Prior - One of the best experts on this subject based on the ideXlab platform.
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in vivo total Antioxidant Capacity comparison of different analytical methods
Free Radical Biology and Medicine, 1999Co-Authors: Ronald L. PriorAbstract:Abstract Several methods have been developed to measure the total Antioxidant Capacity of a biological sample. The use of peroxyl or hydroxyl radicals as pro-oxidants in the oxygen radical absorbance Capacity (ORAC) assay makes it different and unique from the assays that involve oxidants that are not necessarily pro-oxidants. An improvement in quantitation is achieved in the ORAC assay by taking the reaction between substrate and free radicals to completion and using an area-under-curve technique for quantitation compared to the assays that measure a lag phase. The interpretation of the changes in plasma or serum Antioxidant Capacity becomes complicated by the different methods used in detecting these changes. The interpretation also depends upon the conditions under which the Antioxidant Capacity is determined because the measurement reflects outcomes in a dynamic system. An increased Antioxidant Capacity in plasma or serum may not necessarily be a desirable condition if it reflects a response to increased oxidative stress. Similarly, a decrease in plasma or serum Antioxidant Capacity may not necessarily be an undesirable condition if the measurement reflects decreased production of reactive species. Because of these complications, no single measurement of Antioxidant status is going to be sufficient, but a “battery” of measurements, many of which will be described in Forum articles, will be necessary to adequately assess oxidative stress in biological systems.
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Antioxidant Capacity vitamin c phenolics and anthocyanins after fresh storage of small fruits
Journal of Agricultural and Food Chemistry, 1999Co-Authors: Wilhelmina Kalt, Charles F Forney, A Martin, Ronald L. PriorAbstract:Fresh strawberries (Fragaria × ananassa Duch.), raspberries (Rubus idaeus Michx.), highbush blueberries (Vaccinium corymbosum L.), and lowbush blueberries (Vaccinium angustifolium Aiton) were stored at 0, 10, 20, and 30 °C for up to 8 days to determine the effects of storage temperature on whole fruit Antioxidant Capacity (as measured by the oxygen radical absorbing Capacity assay, Cao et al., Clin. Chem. 1995, 41, 1738−1744) and total phenolic, anthocyanin, and ascorbate content. The four fruit varied markedly in their total Antioxidant Capacity, and Antioxidant Capacity was strongly correlated with the content of total phenolics (0.83) and anthocyanins (0.90). The Antioxidant Capacity of the two blueberry species was about 3-fold higher than either strawberries or raspberries. However, there was an increase in the Antioxidant Capacity of strawberries and raspberries during storage at temperatures >0 °C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and ...