Effect of high-oxygen atmospheres on blueberry phenolics, anthocyanins, and antioxidant capacity

The influence of high oxygen concentrations on total phenolic, total anthocyanin, individual phenolic compounds, and antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC) in highbush blueberry fruit (Vaccinium corymbosum L. cv. Duke) was investigated. Freshly harvested blueberries were placed in jars ventilated continuously with air or with 40, 60, 80, or 100% O(2) at 5 degrees C for up to 35 days. Samples were taken initially and at 7-day intervals during storage. Whereas the quality parameters of titratable acidity, total soluble solids, and surface color were only slightly affected by the superatmospheric O(2) treatments, the antioxidant levels were markedly increased by 60-100% O(2) treatments as compared with 40% O(2) treatment or air control during 35 days of storage. Elevated O(2) between 60 and 100% also promoted increases of total phenolics and total anthocyanins as well as the individual phenolic compounds analyzed by HPLC. Fruit treated with O(2) concentrations of >/=60% also exhibited significantly less decay. Data obtained in this study suggest that high-oxygen treatments may improve the antioxidant capacity of blueberry fruit. Furthermore, antioxidant capacity may be correlated with total phenolic and anthocyanin contents in blueberries.     

Antioxidant capacity and phenolic content of spinach as affected by genetics and growing season

Total phenolic content and antioxidant capacity of 11 commercial cultivars and 15 advanced breeding lines of spinach were determined over two growing seasons known to vary in biotic and abiotic stresses. Flavonoid composition and content of fall-grown commercial cultivars and advanced breeding lines were also determined. Over-winter spinach, which was planted in late fall and harvested in the spring, had much higher levels of total phenolics and antioxidant capacity than spinach planted in early fall and harvested in late fall, indicating that growing conditions, as well as biotic and abiotic stresses, influenced phenolic metabolism. Genotype also appeared to play an important role in affecting phenolic metabolism and antioxidant capacity in spinach. Advanced breeding lines of spinach, which show increased disease resistance, had higher levels of total phenolics, individual and total flavonoids, and antioxidant capacity than commercial cultivars. Our results indicate that plant breeders can select for increased phenolic content to increase antioxidant capacity in spinach cultivars, or the crops can be grown in different seasons or under certain stress conditions to elevate levels of antioxidants.     

Storage elevates phenolic content and antioxidant activity but suppresses antiproliferative and pro-apoptotic properties of colored-flesh potatoes against human colon cancer cell lines

Colored-flesh potatoes are an excellent source of health-benefiting dietary polyphenols, but are stored for up to 3-6 months before consumption. This study investigated the effect of simulated commercial storage conditions on antioxidant activity (DPPH, ABTS), phenolic content (FCR) and composition (UPLC-MS), and anticancer properties (early, HCT-116 and advanced stage, HT-29 human colon cancer cell lines) of potato bioactive compounds. Extracts from seven potato clones of differing flesh colors (white, yellow, and purple) before and after 90 days of storage were used in this study. The antioxidant activity of all clones increased with storage; however, an increase in total phenolic content was observed only in purple-fleshed clones. Advanced purple-fleshed selection CO97227-2P/PW had greater levels of total phenolics, monomeric anthocyanins, antioxidant activity and a diverse anthocyanin composition as compared with Purple Majesty. Purple-fleshed potatoes were more potent in suppressing proliferation and elevating apoptosis of colon cancer cells compared with white- and yellow-fleshed potatoes. The extracts from both fresh and stored potatoes (10-30 μg/mL) suppressed cancer cell proliferation and elevated apoptosis compared with the solvent control, but these anticancer effects were more pronounced with the fresh potatoes. Storage duration had a strong positive correlation with antioxidant activity and percentage of viable cancer cells and a negative correlation with apoptosis induction. These results suggest that although the antioxidant activity and phenolic content of potatoes were increased with storage, the antiproliferative and pro-apoptotic activities were suppressed. Thus, in the assessment of the effects of farm to fork operations on the health-benefiting properties of plant foods, it is critical to use quantitative analytical techniques in conjunction with in vitro and/or in vivo biological assays.     

Interspecific variation in anthocyanins, phenolics, and antioxidant capacity among genotypes of highbush and lowbush blueberries (Vaccinium section cyanococcus spp.)

Recent interest in the possible protective effects of dietary antioxidant compounds against human degenerative disease has prompted investigation of foods such as blueberries (Vaccinium sp.), which have a high antioxidant capacity. Fruit obtained from genotypes of highbush blueberries (Vaccinium corymbosum L.) and lowbush blueberries (Vaccinium angustifolium Aiton) were analyzed for their antioxidant capacity, their content of anthocyanins, and total phenolic compounds, to evaluate the intraspecific and interspecific variation in these parameters. The method of extraction influenced the composition of fruit extracts; the highest anthocyanin and total phenolic contents and antioxidant capacity were found in extracts obtained using a solvent of acidified aqueous methanol. Regardless of the method, lowbush blueberries were consistently higher in anthocyanins, total phenolics, and antioxidant capacity, compared with highbush blueberries. There was no relationship between fruit size and anthocyanin content in either species.     

Rowanberry phenolics: compositional analysis and bioactivities

Berries contain a large variety of different phenolic compounds such as anthocyanins, flavonols, tannins, and phenolic acids. Due to variation in the nature and content of the phenolic compounds, the antioxidant effect and other bioactivities of berry phenolics are strongly dependent on the berry raw material as the activities differ between the different phenolic constituents. In the present study, wild rowanberries ( Sorbus aucuparia ) and four cultivated sweet rowanberries, Burka, Granatnaja, Titan, and Zoltaja, were characterized for their phenolic composition and screened for antioxidant, antimicrobial, and antiadhesive activities. The HPLC and LC-MS analyses of phenolic composition revealed that the main phenolic constituents were caffeoylquinic acids, varying from 56 to 80% total phenolics. The cultivated species contained less caffeoylquinic acids and more anthocyanins (up to 28.5%). The phenolics derived from wild rowanberries were significantly effective at inhibiting lipid oxidation both in liposomes and in emulsions, especially when assessed by inhibition of the formation of hexanal (86-97% inhibition depending on concentration). The increase in anthocyanin content in the cultivated species did not result in significantly increased antioxidant activity. Both wild and cultivated rowanberry phenolics exhibited a bacteriostatic effect toward Staphylococcus aureus . In addition, the phenolic extract from Zoltaja was weakly inhibitory toward Salmonella sv. Typhimurium, whereas both Zoltaja- and Granatnaja-derived phenolics retarded Escherichia coli growth. The phenolic extracts of wild rowanberries and Burka showed an inhibitory effect on hemagglutination of E. coli HB101 (pRR7), which expresses the M hemagglutinin. It can be concluded that cultivation of rowanberries resulted in increased anthocyanin content, but this did not diminish their bioactivity in comparison to wild rowanberries rich in caffeoylquinic acids.     

Effect of methyl jasmonate on phenolic compounds and carotenoids of romaine lettuce (Lactuca sativa L.)

The effect of exogenous methyl jasmonate (MeJA) on antioxidative compounds of romaine lettuce ( Lactuca sativa L.) was investigated. Lettuces were treated with various MeJA solutions (0, 0.05, 0.1, 0.25, and 0.5 mM) before harvest. Total phenolic compounds content and antioxidant capacity of romaine lettuce significantly increased after MeJA treatments (0.1, 0.25, and 0.5 mM). The total content of phenolic compounds of the romaine lettuce treated with 0.5 mM MeJA (31.6 microg of gallic acid equivalents/mg of dry weight) was 35% higher than that of the control. The increase in phenolic compound content was attributed to a caffeic acid derivative and an unknown phenolic compound, which also contributed to increased antioxidant capacity. The induction of phenylalanine ammonia-lyase (PAL) activity by the MeJA treatment indicated that phenolic compounds were altered due to the activation of the phenylpropandoid pathway. Total content of carotenoids, including lutein and beta-carotene, of the MeJA-treated lettuce did not change after 8 days of treatment, whereas the content of the control without MeJA decreased after 8 days. This research indicated that preharvest application of MeJA could increase the nutritional value of romaine lettuce under determined conditions discussed in this work.     

Antioxidant capacity, vitamin C, phenolics, and anthocyanins after fresh storage of small fruits.

Fresh strawberries (Fragaria x 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 degrees 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 degrees C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and total phenolics in raspberries. Ascorbate content differed more than 5-fold among the four fruit species; on average, strawberries and raspberries had almost 4-times more ascorbate than highbush and lowbush blueberries. There were no ascorbate losses in strawberries or highbush blueberries during 8 days of storage at the various temperatures, but there were losses in the other two fruit species. Ascorbate made only a small contribution (0.4-9.4%) to the total antioxidant capacity of the fruit. The increase observed in antioxidant capacity through postharvest phenolic synthesis and metabolism suggested that commercially feasible technologies may be developed to enhance the health functionality of small fruit crops.     

Priming of antimicrobial phenolics during induced resistance response towards Pectobacterium carotovorum in the ornamental monocot calla lily

Calla lilies are herbaceous monocotyledonous plants that are highly sensitive to Pectobacterium carotovorum, the causal agent of soft-rot disease. Results demonstrate that, in response to elicitation using plant defense activators, the calla lily produces elevated levels of antimicrobial phenolics and that these compounds contribute to increased resistance against P. carotovorum, as shown by reduced bacterial proliferation in elicited leaves. The polyphenolic nature of the induced compounds was supported by autofluorescence, absorbance spectra, and reaction with Folin-Ciocalteu reagent. Two plant defense activators, Bion and methyl jasmonate, differed in both their capacity to induce accumulation of polyphenols and their resistance against the pathogen. Methyl jasmonate elicitation brought about higher accumulation of free phenolics relative to Bion, suggesting priming of bioactive polyphenols as a principal factor in the calla lily defense against P. carotovorum. To further characterize the nature of induced compounds, two major compounds were collected and identified as swertisin and isovitexin by mass and nuclear magnetic resonance spectroscopies.     

Antioxidant capacity in cranberry is influenced by cultivar and storage temperature

Ten cranberry (Vaccinium macrocarpon Aiton) cultivars were evaluated for oxygen radical absorbance capacity (ORAC), anthocyanins, and total phenolics contents after three months of storage at 0, 5, 10, 15, and 20 degrees C. The antioxidant capacity of cranberry was affected by cultivars and storage temperatures. Among the 10 cranberry cultivars used in this study, Early Black, Crowley, and Franklin had higher antioxidant capacities than the other cultivars. ORAC values, anthocyanins, and total phenolics contents increased during storage. The highest increases in antioxidant activity, anthocyanin, and phenolics contents occurred at 15 degrees C storage. Fruit stored at 20 degrees C had lower ORAC values than those stored at 15 degrees C. A positive relationship existed between ORAC values and anthocyanin or phenolic content in all 10 cranberry cultivars at different storage temperatures.     

Effect of clarification techniques and rat intestinal extract incubation on phenolic composition and antioxidant activity of black currant juice

This study examined the phenolic composition and the antioxidant potencies of black currant juices that had been experimentally clarified with acidic proteases and pectinases to retain the phenolics and which had been subjected to rat intestinal mucosa extract incubation to mimic gut cell mediated biotransformation of phenolics. When compared at equimolar levels of 2.5 microM gallic acid equivalents, the black currant juice samples prolonged the induction time of human low-density lipoprotein oxidation in vitro by 2.6-3.6 times, and the order of antioxidant potency of differently clarified black currant juices was centrifuged juice > gelatin silica sol clarified juice > enzymatically clarified juice approximately raw juice. No immediate relationship between the, almost similar, phenolic profiles of the juice samples and their relative antioxidant activities could be established. Incubation of juices with a rat small intestine cell extract for 19 h promoted significant decreases in the contents of the anthocyanin 3-O-beta-glucosides (cyanidin 3-O-beta-glucoside and delphinidin 3-O-beta-glucoside), but did not affect the anthocyanin 3-O-beta-rutinosides (cyanidin 3-O-beta-rutinoside and delphinidin 3-O-beta-rutinoside) of the black currant juice. Black currant juice samples subjected to such intestinal cell extract incubation had approximately 30% decreased antioxidant capacity. Incubation of juices with the rat small intestine cell extracts at neutral pH appeared to decrease the levels of delphinidin glucosides more than the levels of cyanidin glucosides. The results provide an explanation for the predominant detection of anthocyanin rutinosides, and not anthocyanin glucosides, in plasma and urine in in vivo studies and provide important clues to better understand the complex mechanisms affecting dietary phenols in the gut.     

Improving grape phenolic content and wine chromatic characteristics through the use of two different elicitors: methyl jasmonate versus benzothiadiazole

Benzothiadiazole (BTH) and methyl jasmonate (MeJ) have been described as exogenous elicitors of some plant defense compounds, polyphenols among them. The objective of this study was to determine whether the application of BTH or MeJ to grape clusters at the beginning of the ripening process had any effect on the accumulation of the main flavonoid compounds in grapes (anthocyanins, flavonols, and flavanols) and the technological significance of these treatments in the resulting wines. The results obtained after a 2 year experiment indicated that both treatments increased the anthocyanin, flavonol, and proanthocyanidin content of grapes. The wines obtained from the treated grapes showed higher color intensity and total phenolic content than the wines made from control grapes. The exogenous application of these elicitors, as a complement to fungicide treatments, could be an interesting strategy for vine protection, increasing, at the same time, the phenolic content of the grapes and the resulting wines.     

Stoichiometric and kinetic studies of phenolic antioxidants from Andean purple corn and red-fleshed sweetpotato

Stoichiometric and kinetic values of phenolics against DPPH (2,2-diphenyl-1-picrylhydrazyl) were determined for Andean purple corn (Zea mays L.) and red sweetpotato (Ipomoea batatas). Both crops had higher antioxidant capacity and antiradical kinetics than blueberries and higher or similar anthocyanin and phenolic contents. The second-order rate constant (k(2)) was 1.56, 1.12, 0.57, and 0.26 (mg antiradical/mL)(-1) s(-1) for red sweetpotato, Trolox, purple corn, and blueberry, respectively. On the molar basis of active hydroxyl groups, k(2)' showed the same order as for k(2). Corn cob and sweetpotato endodermis contributed the most in phenolic compounds and antioxidant capacity. Both crops studied can be considered as excellent novel sources of natural antioxidants for the functional food and dietary supplement markets.     

Antioxidant Activity and Characterization of Phenolic Compounds from Bacaba ( Oenocarpus bacaba Mart.) Fruit by HPLC-DAD-MS(n)

The phytochemicals in fruits have been shown to be major bioactive compounds with regard to health benefits. Bacaba ( Oenocarpus bacaba Mart.) is a native palm fruit from the Brazilian savannah and Amazon rainforest that plays an important role in the diet of rural communities and is also a source of income for poor people. This paper reports the characterization and analyses of phenolics from bacaba fruit extract. The total phenolic content of bacaba fruit amounted to 1759.27 ± 1.01 mg GAE/100 g, the flavonoid content was 1134.32 ± 0.03 mg CTE/100 g, and the anthocyanin content was 34.69 ± 0.00 mg cyn-3-glc/100 g. The antioxidant activity was evaluated through different assays [ORAC, FRAP, DPPH, TEAC, and cellular antioxidant assay (CAA) assays] and revealed a significant antioxidant capacity for bacaba in comparison to the data available in the literature. The assignment of the phenolic compounds using HPLC-DAD-MS(n) was based on the evaluation of their UV-vis absorption maxima (λ(max)) and mass spectral analyses, and 14 compounds were tentatively identified. The results suggest that bacaba fruits are a promising source of phenolics.     

Antioxidant capacity of 26 spice extracts and characterization of their phenolic constituents

Total equivalent antioxidant capacity (TEAC) and phenolic content of 26 common spice extracts from 12 botanical families were investigated. Qualitative and quantitative analyses of major phenolics in the spice extracts were systematically conducted by reversed-phase high-performance liquid chromatography (RP-HPLC). Many spices contained high levels of phenolics and demonstrated high antioxidant capacity. Wide variation in TEAC values (0.55-168.7 mmol/100 g) and total phenolic content (0.04-14.38 g of gallic acid equivalent/100 g) was observed. A highly positive linear relationship (R2= 0.95) obtained between TEAC values and total phenolic content showed that phenolic compounds in the tested spices contributed significantly to their antioxidant capacity. Major types of phenolic constituents identified in the spice extracts were phenolic acids, phenolic diterpenes, flavonoids, and volatile oils (e.g., aromatic compounds). Rosmarinic acid was the dominant phenolic compound in the six spices of the family Labiatae. Phenolic volatile oils were the principal active ingredients in most spices. The spices and related families with the highest antioxidant capacity were screened, e.g., clove in the Myrtaceae, cinnamon in the Lauraceae, oregano in the Labiatae, etc., representing potential sources of potent natural antioxidants for commercial exploitation. This study provides direct comparative data on antioxidant capacity and total and individual phenolics contents of the 26 spice extracts.     

Importance of insoluble-bound phenolics to antioxidant properties of wheat

Two commercial samples of soft (70% Canadian Eastern soft red spring and 30% Canadian Eastern soft white winter) and hard (90% Canadian western hard red spring and 10% Canadian Eastern hard red winter) wheats were used to obtain different milling fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Soluble esters of phenolics and insoluble-bound phenolics were extracted into diethyl ether after alkaline hydrolysis of samples. The content of phenolics was determined using Folin-Ciocalteu's reagent and expressed as ferulic acid equivalents (FAE). The antioxidant activity of phenolic fractions was evaluated using Trolox equivalent antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity, inhibition of oxidation of human low-density lipoprotein cholesterol and DNA, Rancimat, inhibition of photochemilumenescence, and iron(II) chelation activity. The bound phenolic content in the bran fraction was 11.3 +/- 0.13 and 12.2 +/- 0.15 mg FAE/g defatted material for hard and soft wheats, respectively. The corresponding values for flour were 0.33 +/- 0.01 and 0.46 +/- 0.02 mg FAE/g defatted sample. The bound phenolic content of hard and soft whole wheats was 2.1 (+/-0.004 or +/-0.005) mg FAE/g defatted material. The free phenolic content ranged from 0.14 +/- 0.004 to 0.98 +/- 0.05 mg FAE/g defatted milling fractions of hard and soft wheats examined. The contribution of bound phenolics to the total phenolic content was significantly higher than that of free and esterified fractions. In wheat, phenolic compounds were concentrated mainly in the bran tissues. In the numerous in vitro antioxidant assays carried out, the bound phenolic fraction demonstrated a significantly higher antioxidant capacity than free and esterified phenolics. Thus, inclusion of bound phenolics in studies related to quantification and antioxidant activity evaluation of grains and cereals is essential.     

From plums to prunes: influence of drying parameters on polyphenols and antioxidant activity

Prunes, which are industrially obtained by dehydrating fresh plums at 85-90 degrees C for 18 h, contain higher levels of phenolic compounds than most other fruits. Prune phenolics have shown beneficial effects on human health. Reports are available in the literature on ascorbic acid, phenol composition, and antioxidant activity of fresh plums and prunes, but there is a lack of publications on the influence of drying parameters on the phenolic compounds and antioxidant activity. A study was carried out on two plum cultivars using two sets of air-drying temperatures: (i) air temperature at 85 degrees C until 50% of prune moisture level and then the temperature was lowered to 70 degrees C; (ii) air temperature at 60 degrees C. Whole fresh and dried fruits were assessed for phenolics (catechins, hydroxycinnamic acids, anthocyanins, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that chlorogenic and neochlorogenic acid changes were affected by both process parameters and cultivar. Drying destroyed anthocyanins, and there was a significant decrease in flavonols. Ascorbic acid was drastically reduced in relation to process temperature. The most striking result was that drying at 85 degrees C doubled antioxidant activity in both cultivars, while contradictory results were found for 60 degrees C processed plums.     

Phenolic composition and antioxidant activities in flesh and achenes of strawberries (Fragaria ananassa)

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.     

Antioxidant properties of wheat as affected by pearling

The effects of pearling on the content of phenolics and antioxidant capacity of two Canadian wheat classes, namely, Canada Western Amber Durum; Triticum turgidum L. var. durum; CWAD) and Canada Western Red Spring; Triticum aestivum L.; CWRS) were examined. The antioxidant activity of wheat phenolics was evaluated using oxygen radical absorbance capacity (ORAC), inhibition of photochemiluminescence (PCL), Rancimat method, inhibition of oxidation of low-density lipoprotein, and DNA. The phenolic composition of wheat extracts was determined using high-performance liquid chromatography. The antioxidant capacity of both pearled grains and byproducts significantly decreased as the degree of pearling increased. Among grains, the unprocessed whole grains demonstrated the highest antioxidant capacity. The byproducts always demonstrated higher antioxidant capacity compared to the pearled grains, regardless of the wheat class. The resultant byproducts from 10-20% pearling possessed the highest antioxidant capacity. Processing of cereals may thus exert a significant effect on their antioxidant activity. The concentration of grain antioxidants is drastically reduced during the refining process. As phenolic compounds are concentrated in the outermost layers, the bran fractions resulting from pearling may be used as a natural source of antioxidants and as value-added products in the preparation of functional food ingredients or for enrichment of certain products.     

Phenolic compounds, carotenoids, anthocyanins, and antioxidant capacity of colored maize (Zea mays L.) kernels

In this study, the contents of total phenolics, flavonoids, anthocyanins, β-carotene, and lutein as well as free, conjugated, and insoluble bound phenolic acids were determined in whole kernels of 10 different colored maize genotypes. In addition, the antioxidant activity was evaluated as radical scavenging activity with ABTS (2,2-azino-bis/3-ethil-benothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) reagents. Generally, considerable differences in phytochemical contents and antioxidant capacity were observed between the genotypes. The β-carotene and lutein contents ranged from 0 to 2.42 mg/kg d.m. and from 0 to 13.89 mg/kg d.m., respectively, whereas the total anthocyanin contents of anthocyanin-rich colored maize genotypes ranged from 2.50 to 696.07 mg CGE/kg d.m. (cyanidin 3-glucoside equivalent) with cyanidin 3-glucoside (Cy-3-Glu) as the most dominant form. The light blue ZPP-2 selfed maize genotype has a higher content of total phenolics, flavonoids, and ferulic acid as compared to other tested maize and the highest ABTS radical scavenging activity.     

日喀则市青稞全籽粒抗氧化品质研究

为揭示日喀则青稞全籽粒所含酚类物质与抗氧化能力间的关系,遴选出抗氧化品质优异的品种,对13份青稞材料的酚类物质含量和抗氧化能力进行了品种间的多重比较分析、酚类物质含量和抗氧化能力的相关分析、抗氧化品质的主成分分析以及品种间的聚类分析。结果表明,按籽粒颜色可将13份青稞品种划分为棕、紫、黑三色,深色(紫色和黑色)品种中花色苷、原花青素、总黄酮和总酚含量较高,且氧化自由基吸收能力(ORAC)、铁离子还原能力(FRAP)、1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力也高于浅色(棕色)品种。ORAC、FRAP、DPPH自由基清除能力与酚类物质含量之间存在显著或极显著相关性,而金属离子螯合能力(MCC)与酚类物质无显著相关性。主成分分析和聚类分析结果表明,可通过籽粒颜色来进行青稞抗氧化品质初筛,深色青稞品种尤其是黑色青稞品种籽粒抗氧化品质最高。研究青稞籽粒酚类物质抗氧化有助于完善青稞抗氧化品质评价体系,为开发青稞抗氧化功能食品筛选出抗氧化能力优异的品种。