首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
This study investigated the antioxidant content and activity of phenolic acids, anthocyanins, α-tocopherol and γ-oryzanol in pigmented rice (black and red rice) brans. After methanolic extraction, the DPPH free radical scavenging activity and antioxidant activity were measured. The pigmented rice bran extract had a greater reducing power than a normal rice bran extract from a long grain white rice. All bran extracts were highly effective in inhibiting linoleic acid peroxidation (60-85%). High-performance liquid chromatography (HPLC) analysis of antioxidants in rice bran found that γ-oryzanol (39-63%) and phenolic acids (33-43%) were the major antioxidants in all bran samples, and black rice bran also contained anthocyanins 18-26%. HPLC analysis of anthocyanins showed that pigmented bran was rich in cyanidin-3-glucoside (58-95%). Ferulic acid was the dominant phenolic acid in the rice bran samples. Black rice bran contained gallic, hydroxybenzoic, and protocatechuic acids in higher contents than red rice bran and normal rice bran. Furthermore, the addition of 5% black rice bran to wheat flour used for making bread produced a marked increase in the free radical scavenging and antioxidant activity compared to a control bread.  相似文献   

2.
Analysis of extracts of Glen Ample raspberries (Rubus idaeus L.) by gradient, reverse phase HPLC with diode array and tandem mass spectrometry identified eleven anthocyanins, including cyanidin-3-sophoroside, cyanidin-3-(2(G)-glucosylrutinoside), cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-sophoroside, pelargonidin-3-(2(G)-glucosylrutinoside), and pelargonidin-3-glucoside. Significant quantities of an ellagitannin, sanguiin H-6, with an M(r) of 1870 were detected along with lower levels of a second ellagitannin, lambertianin C, which has an M(r) of 2804. Other phenolic compounds that were detected included trace levels of ellagic acid and its sugar conjugates along with one kaempferol- and four quercetin-based flavonol conjugates. Fractionation by preparative HPLC revealed that sanguiin H-6 was a major contributor to the antioxidant capacity of raspberries together with vitamin C and the anthocyanins. Vasodilation activity was restricted to fractions containing lambertianin C and sanguiin H-6.  相似文献   

3.
Antioxidant activity-guided fractionation based on three in vitro antioxidant assays (Folin-Ciocalteu, TEAC, and leucomethylene blue assays) was used to identify major antioxidants in blue wheat (UC66049 Triticum aestivum L.). After consecutive extractions with solvents of various polarities and multiple chromatographic fractionations, several potent antioxidants were identified by NMR spectroscopy and mass spectrometry. Anthocyanins (delphinidin-3-glucoside, delphinidin-3-rutinoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside), tryptophan, and a novel phenolic trisaccharide (β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl-(1→6)-(4-hydroxy-3-methoxyphenyl)-β-D-glucopyranoside) were the most active water-extractable constituents. However, anthocyanins were found to be major contributors to the overall blue wheat antioxidant activity only when the extraction steps were performed under acidic conditions. Alkylresorcinols were among the most active antioxidants extractable with 80% ethanol in the TEAC assay. However, this may be due to a color change instead of a bleaching of the ABTS radical. Ferulic acid was found to be the major antioxidant in alkaline cell-wall hydrolysates. The contents of the most active antioxidants were determined.  相似文献   

4.
The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 degrees C) on phenolic acid, flavonol, and anthocyanin content and their antioxidant activities against peroxyl radicals (ROO(*)), superoxide radicals (O(2)(*)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radicals (OH(*)), and singlet oxygen ((1)O(2)) in fruit juice of Earliglow and Kent strawberry (Fragaria x ananassa Duch.) cultivars was studied. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside (291.3-945.1 microg/g fresh wt.), pelargonidin 3-rutinoside (24.7-50.9 microg/g fresh wt.), and pelargonidin 3-glucoside-succinate (62.2-244.0 microg/g fresh wt.) were the predominant anthocyanins in strawberry fruit juice. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins. Strawberry growth in high temperature conditions significantly enhanced the content of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate in strawberry juice. Plants grown in the cool day and cool night temperature (18/12 degrees C) generally had the lowest phenolic acid, flavonols, and anthocyanins. An increase in night temperature from 12 to 22 degrees C, with the day temperature kept constant at 25 degrees C, resulted in a significant increase in phenolic acid, flavonols, and anthocyanins. These conditions also resulted in a significant increase in antioxidant capacity. The highest day/night temperature (30/22 degrees C) yielded fruit with the most phenolic content as well as ROO(*), O(2)(*)(-), H(2)O(2), OH(*), and (1)O(2) radical absorbance capacity. Fruit of Kent cv. strawberry had higher values of phenolic acid, flavonols, anthocyanins, and antioxidant capacities than fruit of Earliglow cv. strawberry under all temperature regimes.  相似文献   

5.
Phenolics in black soybean seed coat (BSSC) are considered to be responsible for the health benefits of black soybean. BSSCs of 60 Chinese varieties were examined for phenolic contents, anthocyanin profiles, and antioxidant activity. Total phenolic and condensed tannin contents ranged from 512.2 to 6057.9 mg gallic acid equivalents/100 g and from 137.2 to 1741.1 mg (+)-catechin equivalents/100 g, respectively. Six anthocyanins (delphinidin-3-glucoside, cyanidin-3-galactoside, cyanidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside) were detected by HPLC. Total anthocyanin contents (TAC) were from 98.8 to 2132.5 mg/100 g, and cyanidin-3-glucoside was the most abundant anthocyanin in all varieties, with a distribution of 48.8-94.1% of TAC. Antioxidant properties detected by DPPH, FRAP, and ORAC methods all showed wide variations ranging from 4.8 to 65.3 μg/100 mL (expressed as EC(50)), from 17.5 to 105.8 units/g, and from 42.5 to 1834.6 μmol Trolox equivalent/g, respectively. Sixty varieties were classified into four groups by hierarchical clustering analysis, and group 4 consisting of nine varieties had the highest phytochemicals content and antioxidant activity.  相似文献   

6.
Several experiments of maceration of a sherry wine vinegar with different fruits (orange, lemon, strawberry, grapefruit, and lime) have been carried out. After optimization (only peel, no heating and seven days as maximum time of maceration), parameters such as polyphenolic content, superoxide anion scavenging ability (related to antioxidant activity) and ascorbic acid content were determined in sherry wine vinegars macerated with two amounts of peel and for two maceration times (3 and 7 days). The analysis of variance pointed to a clear relationship (p<0.01) between type of fruit and amount of peel and polyphenolic content. The factor "time" was practically not significant for any polyphenol. Sherry wine vinegars macerated with different fruits exhibited higher superoxide anion scavenger ability, with the maximum values found for the vinegar macerated with lemon peel. The correlation analysis showed that the superoxide anion scavenger ability of the vinegars macerated, and thus their antioxidant activity, was highly correlated (p<0.01) with several polyphenols, especially with naringin, hesperidin, neohesperidin and gentisic acid and not with the ascorbic acid content.  相似文献   

7.
Cultural system [hill plasticulture (HC) versus matted row (MR)] and genotype interactions affected strawberry fruit quality. In general, fruit soluble solids content, total sugar, fructose, glucose, ascorbic acid, titratable acid, and citric acid contents were increased in the HC system. Fruit from HC also had higher flavonoid contents and antioxidant capacities. Strawberry fruit contains flavonols as well as other phenolic compounds such as anthocyanins and phenolic acids. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside, pelargonidin 3-rutinoside, and pelargonidin 3-glucoside-succinate were the predominant anthocyanins in strawberry fruit. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins in either system. Strawberry fruit from the HC system had significantly higher amounts of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate. Fruits from plants grown in the MR system generally had the lowest contents of phenolic acids, flavonols, and anthocyanins. Strawberry fruit grown under HC conditions had significantly higher peroxyl radicals (ROO*) absorbance capacity (ORAC).  相似文献   

8.
High performance liquid chromatography coupled with diode array and coulometric array detectors were used to characterize and quantify phenolic compounds in achenes and flesh of ripe strawberries (cv Totem and Puget Reliance). Total phenolics and total monomeric anthocyanins were measured and antioxidant activities were evaluated by the FRAP and the ORAC assays. Strawberries contained 1% achenes on a fresh weight basis; however, they contributed to about 11% of total phenolics and 14% of antioxidant activities in strawberries. Ellagic acid, ellagic acid glycosides, and ellagitannins were the main contributors to the antioxidant activities of achenes. The major anthocyanin in flesh was pelargonidin-3-glucoside, whereas achenes consisted of nearly equal amounts of cyanidin-3-glucoside and pelargonidin-3-glucoside. Phenolic content and antioxidant activity of strawberry achenes were reduced by industrial processing. However, the levels were still high and strawberry waste byproduct could thus be a possible source of nutraceuticals or natural antioxidants.  相似文献   

9.
The effect of a simultaneous intake of food or flavonoids on anthocyanins absorption and antioxidant status in pigs was investigated. Twelve male pigs at 27.1 +/- 0.7 kg BW fitted with jugular venous cannulae were maintained in individual metabolic crates. The animals were each given one of three dietary treatments in random order: blackcurrant powder (BC) to give a dose of 100 mg total ACNs/kg BW mixed either with water and sugar (Diet A), cereal (Weet-Bix), milk, and sugar (Diet B), or cereal, milk, sugar, and an additional flavonol (rutin, approximately 100 mg/kg BW) (Diet C). The four major anthocyanins of BC, delphinidin-3-glucoside, delphinidin-3-rutinoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside, were identified and quantified by HPLC-PDA in all three diets. In the pig plasma, four peaks with a reversed pattern to those of anthocyanins in the BC extract were detected. The total amount of anthocyanins absorbed was not significantly different between the three diets, but the rate of absorption and subsequent decline was slower following administration of diet B and C than diet A. All three diets increased antioxidant capacity when measured by the FRAP assay but not when measured by the ORAC and non-protein ORAC assay. However, the increase was delayed and did not appear until 4 h after ingestion, at a time when plasma anthocyanin levels had returned to baseline. The present study demonstrates that the simultaneous intake of food or other flavonoids delays the absorption profile for anthocyanins. Our results also suggest that the increase in antioxidant capacity is not due to dietary anthocyanins but may be due to metabolites that result from anthocyanin consumption.  相似文献   

10.
Total phenolics, total flavonoids, and antioxidant capacity of 11 cultivars of fresh plums were determined using spectrophotometric methods. Identification and quantification of individual polyphenolics were performed using reversed-phase high-performance liquid chromatography equipped with a diode array detector. The total phenolic contents of various cultivars widely varied from 125.0 to 372.6 mg/100 g expressed as gallic acid equivalents. The level of total flavonoids in fresh plums ranged between 64.8 and 257.5 mg/100 g expressed as catechin equivalents. Antioxidant capacity, expressed as vitamin C equivalent antioxidant capacity (VCEAC), ranged from 204.9 to 567.0 mg/100 g with an average of 290.9 mg/100 g of fresh weight. Cv. Beltsville Elite B70197 showed the highest amounts of total phenolics and total flavonoids and the highest VCEAC. A positive relationship (correlation coefficient r (2)() = 0.977) was presented between total phenolics and VCEAC, suggesting polyphenolics would play an important role in free radical scavenging. The level of IC(50) value of superoxide radical anion scavenging activity of the plum cultivars ranged from 13.4 to 45.7 mg of VCEAC/100 g. Neochlorogenic acid was the predominant polyphenolic among fresh plums tested. Flavonols found in plum were commonly quercetin derivatives. Rutin was the most predominant flavonol in plums. Various anthocyanins containing cyanidin aglycon and peonidin aglycon were commonly found in all plums except for cv. Mirabellier and NY 101.  相似文献   

11.
One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.  相似文献   

12.
The effects of boiling and steaming processes on the phenolic components and antioxidant activities of whole yellow (with yellow seed coat and yellow cotyledon) and black (with black seed coat and green cotyledon) soybeans were investigated. As compared to the raw soybeans, all processing methods caused significant (p < 0.05) decreases in total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), monomeric anthocyanin content (MAC), DPPH free radical scavenging activity (DPPH), ferric reducing antioxidant power (FRAP), and oxygen radical absorbing capacity (ORAC) in black soybeans. Pressure steaming caused significant (p < 0.05) increases in TPC, CTC, DPPH, FRAP, and ORAC in yellow soybeans. The steaming resulted in a greater retention of TPC, DPPH, FRAP, and ORAC values in both yellow and black soybeans as compared to the boiling treatments. To further investigate the effect of processing on phenolic compounds and elucidate the contribution of these compounds to changes of antioxidant activities, phenolic acids, isoflavones, and anthocyanins were quantitatively determined by HPLC. The pressure steaming treatments caused significant (p < 0.05) increases in gallic acid and 2,3,4-trihydroxybenzoic acid, whereas all treatments caused significant (p < 0.05) decreases in two predominant phenolic acids (chlorogenic acid and trans-cinnamic acid), and total phenolic acids for both yellow and black soybeans. All thermal processing caused significant (p < 0.05) increases in aglucones and beta-glucosides of isoflavones, but caused significant (p < 0.05) decreases in malonylglucosides of isoflavones for both yellow and black soybeans. All thermal processing caused significant (p < 0.05) decreases of cyanidin-3-glucoside and peonidin-3-glucoside in black soybeans. Significant correlations existed between selected phenolic compositions, isoflavone and anthocyanin contents, and antioxidant properties of cooked soybeans.  相似文献   

13.
The phenolics from different strawberry cultivars (Aromas, Camarosa, Diamante, Medina, and Ventana) cultivated in two different soilless systems (with and without recycling nutrient solution) were quantified to assess differences in their profiles as a function of both the variety and the cultivation system. Considering groups of phenols, it was found that either anthocyanins (including pelargonidin-3-glucoside, cyanidin-3-glucoside, pelargonidin-3-rutinoside, pelargonidin-3-acetylglucoside, and two unidentified pelargonidin derivatives) or phenolic acids (including caffeic, ferulic, p-coumaric, p-hydroxybenzoic, and ellagic acid) were quantitatively more important than those of flavonols (quercetin and kaempferol); the ranges of values were 78.81-198.88, 49.77-128.37, and 12.85-43.04 microg/g, respectively. Considering individual compounds and after applying relevant pattern recognition techniques, it was concluded that the contents of cyanidin-3-glucoside, pelargonidin-3-rutinoside, p-coumaric acid, and pelargonidin-3-glucoside were the most appropriate variables to discriminate among varieties, whereas those of p-hydroxybenzoic acid and pelargonidin-derivative 1 were the most appropriate to discriminate between cultivation systems. The first factor of PCA was mainly linked to anthocyanins and quercetin, whereas the second principal component (PC) was related to kaempferol and p-coumaric acid.  相似文献   

14.
Swiss red wheat grain, bran, aleurone, and micronized aleurone were examined and compared for their free radical scavenging properties against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*), radical cation ABTS*+ and peroxide radical anion O(2)*-, oxygen radical absorbance capacity (ORAC), chelating capacity, total phenolic content (TPC), and phenolic acid composition. The results showed that micronized aleurone, aleurone, bran, and grain may significantly differ in their antioxidant properties, TPC, and phenolic acid composition. Micronized aleurone had the greatest antioxidant activities, TPC, and concentrations of all identified phenolic acids, suggesting the potential of postharvesting treatment on antioxidant activities and availability of TPC and phenolic acids. Ferulic acid was the predominant phenolic acid in Swiss red wheat and accounted for approximately 57-77% of total phenolic acids on a weight basis. Ferulic acid concentration was well correlated with scavenging activities against radical cation and superoxide anion, TPC, and other phenolic acid concentrations, suggesting the potential use of ferulic acid as a marker of wheat antioxidants. In addition, 50% acetone and ethanol were compared for their effects on wheat ORAC values. The ORAC value of 50% acetone extracts was 3-20-fold greater than that of the ethanol extracts, indicating that 50% acetone may be a better solvent system for monitoring antioxidant properties of wheat. These data suggest the possibility to improve the antioxidant release from wheat-based food ingredients through postharvesting treatment or processing.  相似文献   

15.
Studies suggest that consumption of berry fruits, including strawberries ( Fragaria x ananassa Duch.), may have beneficial effects against oxidative stress mediated diseases such as cancer. Berries contain multiple phenolic compounds, which are thought to contribute to their biological properties. Comprehensive profiling of phenolics from strawberries was previously reported using high-performance liquid chromatography with mass spectrometry (HPLC-MS) detection. The current study reports the isolation and structural characterization of 10 phenolic compounds from strawberry extracts using a combination of Amberlite XAD16-resin and C18 columns, HPLC-UV, and nuclear magnetic resonance (NMR) spectroscopy methods. The phenolics were cyanidin-3-glucoside ( 1), pelargonidin (2), pelargonidin-3-glucoside (3), pelargonidin-3-rutinoside (4), kaempferol (5), quercetin (6), kaempferol-3-(6'-coumaroyl)glucoside) (7), 3,4,5-trihydroxyphenyl-acrylic acid (8), glucose ester of ( E)- p-coumaric acid (9), and ellagic acid . Strawberry crude extracts and purified compounds 1- 10 were evaluated for antioxidant and human cancer cell antiproliferative activities by the Trolox equivalent antioxidant capacity (TEAC) and luminescent ATP cell viability assays, respectively. Among the pure compounds, the anthocyanins 1 (7156 microM Trolox/mg), 2 (4922 microM Trolox/mg), and 4 (5514 microM Trolox/mg) were the most potent antioxidants. Crude extracts (250 microg/mL) and pure compounds (100 microg/mL) inhibited the growth of human oral (CAL-27, KB), colon (HT29, HCT-116), and prostate (LNCaP, DU145) cancer cells with different sensitivities observed between cell lines. This study adds to the growing body of data supporting the bioactivities of berry fruit phenolics and their potential impact on human health.  相似文献   

16.
High-performance liquid chromatography coupled with a coulometric array detector was used to characterize the electrochemical behavior of 17 flavonoids and three cinnamic acid derivatives. The antioxidant activity of these phenolic compounds was evaluated by the ferric reducing activity power (FRAP), the oxygen radical absorbance capacity (ORAC), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assays. All flavonoids, except kaempferol-3-rutinoside, malvidin-3-glucoside, and peonidin-3-glucoside, had two oxidation potentials (100-300 and 700-800 mV). Quercetin and myricetin had an additional oxidation wave at 400 mV. The electrochemical responses at a relatively low oxidation potential (300 mV) and the cumulative responses at medium oxidation potentials (400 and 500 mV) had the highest correlations with antioxidant activities. The highest correlations between electrochemical characteristics and antioxidant activities were found between electrochemical responses and antioxidant activities obtained in the FRAP assay and in the DPPH assay after short reaction periods. Lower correlations were revealed between electrochemical responses and antioxidant activities obtained in the ORAC assay.  相似文献   

17.
The antimutagenic and antioxidant potentials of rooibos (Aspalathus linearis) tea samples, collected from each of its major processing stages, were evaluated according to the Salmonella typhimurium mutagenicity test and the hydrogen donating ability and superoxide anion radical scavenging assays, respectively. Ten random samples were collected before and after fermentation, as well as after sun-drying, sieving, and steam pasteurization. Results indicated that the fermented tea had a significantly (P < 0.05) lower antimutagenic and antioxidant potential than the unfermented tea. Of the different processing stages, the most significant reduction in the antimutagenic and antioxidant property of the tea was found during the "fermentation" step. Sun-drying, sieving, and steam pasteurization also reduced the antimutagenic potential of the tea, although not to the same extent as the first processing step. The hydrogen donating ability was significantly increased after steam pasteurization in comparison to those of fermented and sun-dried tea. Pasteurization did not affect superoxide anion radical scavenging in comparison to fermented tea. Differences seem to exist in the antimutagenicity and antioxidant potencies of the tea sampled at the various stages during processing. A possible role of tea polyphenols in the antimutagenic and antioxdant activities of the tea is suggested as processing caused a significant reduction in the total polyphenolic content.  相似文献   

18.
Selected native Australian fruits, muntries (Kunzea pomifera F. Muell., Myrtaceae), Tasmanian pepper berry (Tasmanian lanceolata R. Br., Winteraceae), Illawarra plum (Podocarpus elatus R. Br. ex Endl., Podocarpaceae), Burdekin plum (Pleiogynium timorense DC. Leenh, Anacardiaceae), Cedar Bay cherry (Eugenia carissoides F. Muell., Myrtaceae), Davidson's plum (Davidsonia pruriens F. Muell. var. pruriens, Davidsoniaceae), and Molucca raspberry (Rubus moluccanus var. austropacificus van Royen, Rosaceae), were evaluated as sources of antioxidants by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays and compared with blueberry (Vaccinum spp. cv. Biloxi). The total reducing capacity of five fruits was 3.5-5.4-fold higher than that of blueberry, and the radical scavenging activities of muntries and Burdekin plum were 1.5- and 2.6-fold higher, respectively. The total phenolic level by Folin-Ciocalteu assay highly correlated with the antioxidant activity. Therefore, systematic research was undertaken to identify and characterize phenolic complexes. In the present study we report on the levels and composition of anthocyanins. The HPLC-DAD and HPLC/ESI-MS-MS (ESI = electrospray ionization) analyses revealed simple anthocyanin profiles of one to four individual pigments, with cyanidin as the dominating type. This is the first evaluation of selected native Australian fruits aiming at their utilization for the development of novel functional food products.  相似文献   

19.
The effect of selected phenolic compounds, namely, gallic acid, cyanidin-3-glucoside, (+)-epicatechin, chlorogenic acid, genistein and rutin (50 and 200 microM), and alpha-tocopherol (50 microM) against the oxidation of oil-in-water emulsions (37 degrees C/10 days) containing 1% myofibrillar proteins (MPs), was investigated. Emulsions containing 1% bovine serum albumin (BSA) were also prepared for comparative purposes. Protein oxidation was assessed by measuring the loss of natural tryptophan fluorescence and the protein carbonyl gain by using fluorescence spectroscopy. Lipid oxidation was concurrently analyzed by measuring the increase of conjugated dienes (CDs) and hexanal. Proteins inhibited lipid oxidation in oil-in-water emulsions, and MPs showed a more intense antioxidant activity than BSA. MPs were also more resistant to oxidative deterioration than BSA. The different antioxidant capacity of MPs and BSA and their susceptibility to suffer oxidative reactions might be derived from their different amino acid composition and three-dimensional structures. The addition of the phenolic compounds resulted in a variety of effects, including both antioxidant and pro-oxidant effects. Gallic acid, cyanidin-3-glucoside, and genistein were the most efficient inhibitors of lipid and protein oxidation. The chemical structure of the phenolic compounds as well as the nature and conformation of the proteins were greatly influential on the overall effect against oxidative reactions.  相似文献   

20.
An electron spin resonance (ESR) spectrometry study was conducted to examine the free radical scavenging properties of bran extracts of Alliance and Wichita wheat using hydroxyl radical (HO*), 2,2-diphenyl-1-picryhydrazyl radical (DPPH*), and superoxide radical anion (O2*-) and their chelating capacities against Cu2+. Also reported is the radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*+) scavenging activity, oxygen radical absorbing capacity (ORAC), and chelating property against Fe2+ of the bran extracts measured by the spectrophotometric methods. Significant radical scavenging and chelating capacities were detected in the bran extracts, along with significant levels of phenolic acids, tocopherols, and carotenoids. Ferulic acid, with a concentration range of 130.60-146.38 microg/g, was the predominant phenolic acid in all of the tested bran samples and accounted for approximately 53-67% of total phenolic acids on a weight basis. Total tocopherol concentration ranged from 1.87 to 2.95 micromol/100 g of bran, whereas total carotenoid level was 0.20-0.33 micromol/100 g of bran. In addition, both wheat variety and growing conditions might significantly alter antioxidant properties and concentrations of beneficial components in wheat bran.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号