Cultivars, culture conditions, and harvest time influence phenolic and ascorbic acid contents and antioxidant capacity of strawberry (Fragaria x ananassa)

Strawberries are a good source of micronutrients, especially antioxidant phenolics. More information is needed to better exploit the health-promoting effect of such fruits. Several studies focused on the effects of genotype, cultural practices, and seasonal variation on the antioxidant potential of strawberries, but often yielding contradictory results and/or focusing on only 1 source of variability. In the present study, we showed that total phenolic compounds, ascorbic acid, and antioxidant capacity strongly differed between genotypes of strawberry. The precise results revealed the importance of genetic background for the antioxidant capacity and for the content of total phenolics (with up to 3.3-fold variations). Other parameters may also influence the antioxidant capacity in strawberry such as harvest time, culture conditions, and environmental factors. Moreover, in this study, the harvesting time (at the same ripening stage) appeared to be very important, more important than genotype. Variations of the antioxidant capacity of up to 4.1-folds were observed following the harvesting time of "Elsanta" cultivar. PRACTICAL APPLICATION: This article compares the antioxidant capacity and the content in ascorbic acid and phenolic compounds of strawberries of different varieties and of fruits harvested from April to December at the same ripening stage. The importance of strawberry antioxidant capacity resides in its benefits for human health.     

Daily consumption of phenolics and total antioxidant capacity from fruit and vegetables in the American diet

The daily intake of total phenolics, total flavonoids and antioxidants in the American diet was estimated from the most common 34 fresh fruit and vegetables and their daily consumption data. Among 14 fruit and 20 vegetables, orange contributed the highest amount of total phenolics [117.1 mg gallic acid equivalent (GAE) person^?1 day^?1] and antioxidants [146.6 mg vitamin C equivalents (VCE) person^?1 day^?1]. Orange contributed about 26 and 25% of total phenolics and antioxidant, respectively, in the daily consumption of fruit and vegetables. Apples showed relatively high levels of total phenolics and antioxidant capacity comparable to those of oranges and their phenolics and antioxidants contribution is the second highest. Even though potatoes had lower levels of phenolics and antioxidant capacity, they were third due to the fact that their consumption is the highest (137.9 lb person^?1 year^?1) in the American diet. Although plums and strawberries were ranked as the group with the highest total phenolics and antioxidant capacity among 34 tested fruit and vegetables, their contributions were relatively low due to their lower daily consumption. Generally, the levels of total phenolics, total flavonoids and antioxidant capacity of fruits were higher than those of vegetables. American daily intake of phenolics, flavonoids and antioxidants from fruits and vegetables was estimated to be 450 mg GAE, 103 mg catechin equivalents and 591 mg VCE, respectively. Although we do not yet know the required minimum daily amounts of antioxidants, when we estimate the daily requirement of antioxidants, we must consider not only the antioxidant concentrations of the particular food, but also the daily intakes of the food. Copyright © 2005 Society of Chemical Industry     

酸荔枝核黄酮体外抗氧化作用的研究

为探讨酸荔枝核总黄酮的提取工艺及体外抗氧化作用.采用正交试验乙醇热浸的方法考察提取溶剂浓度、提取时间、料液比等因素对酸荔枝核总黄酮提取率的影响.结果以液固比20∶1,提取时间30min,乙醇体积百分数为95％vol这3个因素为最佳.酸荔枝核中总黄酮对DPPH和氧自由基这2种自由基有很好的清除作用以及还原能力.     

四种豆类中多酚、类黄酮含量及抗氧化活性研究

对豇豆、红小豆、绿豆和蚕豆4种豆类中游离态和结合态的多酚及类黄酮的含量进行测定,并比较了其体外抗氧化活性。数据表明,4种不同豆类的游离态多酚和结合态多酚含量范围分别为1.35～1.75 mg/g和8.63～10.11 mg/g;游离态类黄酮和结合态类黄酮含量范围分别为1.58～2.07 mg/g和3.92～5.08 mg/g;其中结合态多酚含量是游离态多酚的5倍以上,结合态类黄酮含量是游离态的2倍以上。4种豆类游离态和结合态提取物均具有良好的抗氧化活性,其中游离态提取物对DPPH自由基的清除能力明显高于结合态,而结合态对FRAP、ABTS、O2-自由基的清除能力明显高于游离态。豆类中含有丰富的酚类、类黄酮等物质,并且主要以结合态形式存在,具有较强的抗氧化活性。     

不同品种蓝莓酒抗氧化能力及其多酚含量分析

本实验对6个不同品种的蓝莓酒的总酚、总类黄酮、原花青素、总花色苷和总抗氧化能力及其相关性进行了分析,结果发现,不同品种的总酚、总类黄酮、原花青素、总花色苷和总抗氧化能力变幅和变异系数较大,存在显著差异(p＜0.05);蓝莓酒总抗氧化能力与总酚、总类黄酮、原花青素和总花色苷含量之间存在显著性的相关性(p＜0.01),其中与原花青素的相关性最强,达到0.898.     

蔬菜抗氧化能力及与酚酸和总黄酮相关性研究

分析常见蔬菜总抗氧化活性,探讨蔬菜抗氧化能力与酚酸、总黄酮的相关性。采用ABTS、DPPH与FRAP法测定10种常见蔬菜的抗氧化能力,采用Folin-Ciocalteu法测总酚酸,硝酸铝-亚硝酸钠-氢氧化钠法测总黄酮,采用matlab软件进行拟合抗氧化与酚酸、总黄酮的函数方程。结果表明:抗氧化活性与主要抗氧化物质(酚酸和黄酮)的函数关系为Z=-137.743 2-0.918 2 X2+0.211 2Y2-0.422 9 XY+52.843 5 X+2.229 9Y。当总黄酮在6～26mg/100g时,总黄酮、酚酸的量对总抗氧化活性有促进作用;而在27～54mg/100g范围内,总黄酮和酚酸的含量对总抗氧化能力具有一定的抑制作用。     

Antioxidant capacity of fresh‐cut vegetables exposed to ionizing radiation

The effect of ionizing radiation on antioxidant capacity, phenolic content and tissue browning of three vegetables was studied. Midrib and non‐midrib leaf tissues of Romaine and Iceberg lettuce and endive were irradiated with gamma‐rays at 0, 0.5, 1 and 2 kGy, and then stored at 7–8 °C for 8 days. Antioxidant capacity and phenolic content of tissues as well as tissue browning were analyzed at 1, 4 and 8 days of storage. In general, irradiation increased the phenolic content and antioxidant capacity of both tissue types of all vegetables at day 4 and day 8. The rates of the increase were higher in midrib tissues than in non‐midribs, and increased with storage time. Irradiation, however, increased tissue browning of midrib tissues of Romaine and Iceberg lettuce. Our results suggest that irradiation increased nutritional quality of leafy vegetables, but some adverse visual quality changes were encountered. Published in 2005 for SCI by John Wiley & Sons, Ltd.     

香榧仁油中不同形态酚类物质的提取优化及抗氧化能力评价

为提高香榧仁油中不同形态酚类物质的提取得率及探究不同储藏方式下各形态酚类物质的抗氧化能力变化规律,通过单因素实验优化香榧仁油中可溶性部分的游离态酚、酯化态酚以及不溶性结合态酚的提取条件,应用优化后的方法提取常温储藏和冷藏(4℃)1年后的香榧仁油中的不同形态酚类物质,分析其总酚含量并测定DPPH、ABTS自由基清除活性和铁离子还原能力。结果表明：使用甲醇-丙酮-水(7∶7∶6)萃取分离香榧仁油中可溶、不溶性酚类物质效果较好;可溶酯化态酚和不溶性结合态酚碱解的最适碱液浓度、时间和温度分别为0.5 mol/L、6 h、30℃和0.5 mol/L、6 h和40℃;可溶游离态酚及水解后释放的结合态酚使用石油醚-乙酸乙酯(1∶1)提取4次效率较高。常温储藏和冷藏条件下香榧仁油中不同形态酚类物质按含量排序分别为：游离态>酯化态>不溶性结合态、酯化态>游离态>不溶性结合态;冷藏香榧仁油中的酚含量总和、3种形态酚的DPPH及ABTS自由基清除活性和结合态酚的铁离子还原能力均高于常温储藏香榧仁油,冷藏油中酚类物质抗氧化能力总体优于常温储藏油。     

Antioxidant capacity of the Spanish Mediterranean diet

The objective of this work was to determine the total dietary antioxidant capacity (TDAC) of the Spanish Mediterranean diet. The antioxidant capacity of plant foods and beverages included in National food consumption data was determined. TDAC of the Spanish diet was estimated at 6014 and 3549 μmol trolox equivalents by FRAP (ferric reducing antioxidant power) and ABTS (free radical-scavenging capacity) procedures, respectively. About 68% of TDAC came from beverages and 20% from fruits and vegetables, with a very low contribution from cereals. The capacity to inhibit in vitro LDL oxidation of plant foods and beverages was consistent with their antioxidant capacity. The recommended daily intakes of antioxidant vitamins, C and E, represent about 10% of TDAC. Total phenolics intake was estimated as 1171 mg gallic acid/person/day by the Folin–Ciocalteau method. TDAC may be a parameter to be considered in nutritional and epidemiological studies.     

中国绿茶传统加工过程中抗氧化物质含量及抗氧化活性的变化

研究中国绿茶传统加工过程不同工艺阶段茶汤总酚、总黄酮、抗坏血酸含量和抗氧化能力的变化。加工成品的总酚含量从鲜叶的119.91mg/g(以干质量计)下降到100.33mg/g,总黄酮含量也有相似的变化趋势,从2.90mg/g下降到2.04mg/g,且这两种成分的降低主要发生在“回潮”阶段。此外,加工过程中茶汤抗坏血酸含量也逐渐下降(从4.17mg/g降至2.95mg/g)。尽管经过剧烈的加工,鲜叶总抗氧化能力(TEAC)仅出现轻微降低,TEAC从(524.94±18.68)μmol/g降至成品中的(487.03±17.97)μmol/g,但总酚和总黄酮与TEAC无线性关系(R2=0.19,R2= 0.01),而DPPH自由基与总酚和总黄酮有较好的线性关系(R2=0.77,R2=0.56)。此外,加工过程中茶叶抗自动氧化能力增强(抑制率从52.45%增加至78.12%)。表明中国绿茶传统加工过程导致成品茶汤主要抗氧化物质含量的减少,但仅导致其抗氧化能力的轻微改变。     

Juice components and antioxidant capacity of four Tunisian Citrus varieties

BACKGROUND: Juices from four Citrus species of Tunisia were investigated mainly for quality parameters and antioxidant capacity. RESULTS: Citrus reticulata (mandarin) juice had the highest content of total flavonoids (85.33 mg CE L^?1). The latter also occurred in high quantity (82.01 mg CE L^?1) in Citrus lemon (lemon) juice which was also marked by its richness in total aroma (70.16 µg mL^?1) and in total fatty acids (48.10 µg mL^?1). Mandarin and lemon juices had the highest antioxidant activity, as determined b the β‐carotene bleaching assay (26.67% and 22.67%, respectively). Citrus aurantium (bitter orange) juice was characterised by the highest content of total polyphenols (784.67 mg GAE L^?1) and by the greatest inhibition of DPPH (96.10%). Citrus sinensis (blood orange) juice was only marked by the high quantity of ascorbic acid (36.90 mg mL^?1). GC/MS analysis of juice aroma showed the predominance of limonene (48.85–69.59%) in mandarin and in bitter and blood oranges, but of camphene (89.05%) in lemon. GC analysis of juice fatty acids revealed their richness in oleic acid (23.13–39.52%). HPLC analysis of juice phenolics indicated the predominance of phenolic acids (73.13–86.40%). CONCLUSION: The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition. Copyright © 2010 Society of Chemical Industry     

Effects of industrial tomato paste processing on ascorbic acid, flavonoids and carotenoids and their stability over one-year storage

BACKGROUND : The effects of industrial tomato paste processing and long‐term (12 months) ambient storage on the content and stability of quercetin, kaempferol, ascorbic acid (AA), dehydroascorbic acid (DHAA), β‐carotene and lycopene were evaluated in a commercially produced tomato paste. RESULTS : The initial thermal treatment (hot break; 93 °C for 5 min) resulted in significant reductions in quercetin (54%), kaempferol (61%), AA (63%) and β‐carotene (30%), whereas subsequent processing steps (e.g. evaporation and sterilization) did not result in marked changes in these compounds. Lycopene was stable during hot break but decreased by 20% through evaporation and sterilization. The ratio of DHAA:vitamin C increased during hot break to 23%, whereas the ratio of DHAA:vitamin C remained relatively low in subsequent processing steps, indicating that AA was not oxidized. AA decreased with prolonged storage, with only 13% remaining at 12 months. The carotenoids and quercetin remained stable through 12 months of ambient storage. CONCLUSIONS : Tomato pomace contained significant amounts of carotenoids and flavonoids, indicating that it may be an underutilized processing byproduct. Copyright © 2011 Society of Chemical Industry     

Pressurized liquid extraction of flavonoids from spinach

ABSTRACT:  Pressurized liquid extraction (PLE) using water and a 70:30 mixture of ethanol and water over the temperature range of 50 to 190 °C was used to extract flavonoids from dried spinach. The total phenolic content, antioxidant capacity, color, and browning indices of the extracts were also evaluated. PLE using a 70:30 mixture of ethanol and water was more effective than water in extracting flavonoids from spinach. Flavonoids were effectively extracted over the temperature band of 50 to 130 °C with water and 50 to 150 °C with ethanolic solvent. Levels of total phenolics and ORAC values increased with increasing extraction temperature, indicating that flavonoids were minor contributors to antioxidant capacity at elevated extraction temperatures. Browning of ethanolic extracts correlated highly with ORAC values over the temperature range of 50 to 190 °C, and the ORAC values of the large molecular weight fraction (> 1000 Da) increased linearly over the temperature range, indicating that Maillard polymers were the major contributors to antioxidant capacity. The results illustrate that PLE temperatures of < 130 °C for water or < 150 °C for ethanolic solvent may be used to extract flavonoids, followed by a high temperature (> 170 °C) extraction to generate antioxidant-rich moieties.     

重庆地方名柚果肉酚类物质含量及其抗氧化活性分析

通过紫外分光光度计法和高效液相色谱法分别测定10 种重庆地方名柚成熟果实囊衣、汁胞2 个部位的总酚、总黄酮含量及类黄酮、酚酸组分和含量,并采用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）、铁离子还原能力（ferric reducing antioxidant power,FRAP）测定、2,2’-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS）3 种方法对其抗氧化活性进行评价。结果表明：囊衣的总黄酮含量和类黄酮含量较高,‘琯溪蜜柚’总黄酮含量最高达10.97 mg/g,类黄酮中地奥司明含量最高,均值为1 000.72 μg/g,其含量最高为‘五布柚’,达到2 366.77 μg/g;汁胞的总酚含量和酚酸含量较高,‘真龙柚3号’总酚含量最高达8.84 mg/g,酚酸中没食子酸含量最高,均值为1 040.16 μg/g,其含量最高为‘长寿沙田柚’,达到1 325.89 μg/g。利用DPPH法和FRAP法测定2 个部位抗氧化活性,汁胞高于囊衣,ABTS法则囊衣高于汁胞。综合抗氧化能力指数表明,‘琯溪蜜柚’囊衣、‘梁平柚78-8’汁胞的抗氧化活性最强。通过本研究,不仅能够了解重庆地方名柚果实囊衣、汁胞部位酚类物质组分和含量,同时为柑橘酚类物质的应用选择提供了一定的理论依据,促进了柑橘果品营养学的发展。     

Antioxidant and antiinflammation capacities of some pear cultivars

Abstract: Five commercial pear cultivars were investigated for total phenolics and flavonoids contents, the main phenolic compounds, and their antioxidant and antiinflammation capacities. Four in vitro oxidant and 2 in vivo antiinflammation models were used to evaluate the pharmacological activities of the different pears. The main phenolic compounds were determined by high‐performance liquid chromatography with diode‐array detector, which result indicated that gallic acid ranged from 5.23 to 10.72 μg/g, catechin from 0.41 to 28.83 μg/g, chlorogenic acid from 485.11 to 837.03 μg/g, caffeic acid from 0 to 1.16 μg/g, epicatechin from 6.73 to 131.49 μg/g, and rutin from 0.92 to 104.64 μg/g. The total antioxidant capacity was in descending order: Shuijing > Fengshui > Xuehua > Ya > Xiang pear, which was consistent with the total phenol and flavonoid contents. Thus, the antioxidant capacity of pears may be attributed to their high contents of phenolics and flavonoids. However, the antiinflammation activity was in decreasing order: Xuehua > Xiang > Ya > Fengshui > Shuijing pear, which indicates that compounds other than antioxidants may be responsible for the antiinflammation effect. Practical Application: The importance on antioxidant activities of phenolic compounds in foods and vegetables as natural antioxidants has reached a new high in recent years. In this study, the total phenol and flavonoid contents, and the antioxidant and antiinflammation activities of 5 different types of commercial pears in China were investigated, which may be the experimental basis for the further development and utilization of the pears.     

蓝莓叶不同溶剂提取物抗氧化活性研究

研究蓝莓叶不同溶剂提取物中总酚和黄酮的含量以及抗氧化活性。分别用水、甲醇、乙醇、乙酸乙酯、氯仿、石油醚等不同极性溶剂提取蓝莓叶中的活性物质,采用Folin-Cioeaile法、三氯化铝显色法分别测定不同提取物中总酚和黄酮的含量;应用1,1-二苯基-2-三硝基苯肼（DPPH）自由基和2,2-联氮基双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）自由基清除体系及β-胡萝卜素-亚油酸体系评价其抗氧化活性,考察活性物质含量与抗氧化活性的关系。结果表明,蓝莓叶提取物的抗氧化活性随提取溶剂极性的减小而减小。水提取物具有较强的抗氧化活性,其清除DPPH·和ABTS+·的EC50分别为（12.78±0.10）、（6.35±0.03）μg/mL,抑制β-胡萝卜素淬灭IC50值为（25.33±0.02）μg/mL。含量测定显示水提物中总酚含量最高,为（264.67±0.29）mg/g,而甲醇提取物中黄酮含量最高,为（68.94±0.08）mg/g,相关性分析表明,不同溶剂提取物抗氧化能力差别较大,总酚和黄酮含量与抗氧化能力具有相关性,提示水可作为蓝莓叶抗氧化活性物质提取的优选溶剂,而总酚和黄酮含量可作为蓝莓叶抗氧化提取物的质量评价指标。      

成熟期对冬枣多酚含量及其抗氧化活性的影响

研究了全绿、绿白、半红和全红四个成熟期冬枣果实的果皮和果肉中游离态、酯化态和结合态的酚含量以及其总抗氧化能力、清除DPPH自由基和铁还原能力的变化。结果表明,冬枣果实酚类物质主要以游离态和酯化态形式存在于果皮当中,全红期果皮以结合态为主。冬枣果皮中游离态和酯化态酚类物质对总抗氧化能力、清除DPPH自由基和铁还原能力起主要作用。半红期冬枣果实酚含量最多以及其抗氧化活性最为突出。      

草莓、黑莓、蓝莓中多酚类物质及其抗氧化活性研究

研究草莓、黑莓、蓝莓3种小浆果的总酚、总黄酮、原花青素含量及其总抗氧化能力。结果表明:蓝莓全果的总酚、总黄酮、原花青素含量在所测3种浆果全果中最高,分别为9.44mg没食子酸/g干质量、36.08mg芦丁/g干质量、24.38mg儿茶素/g干质量;其总抗氧化能力也最强,达14.98mmol Trolox/100g干质量。草莓的总酚、总黄酮、原花青素含量则最低,抗氧化能力也最弱。此外,3种浆果果渣中的总酚、总黄酮、原花青素含量以及总抗氧化能力均高于全果和果汁,即果渣>全果>果汁。总酚含量、总黄酮含量以及原花青素含量与总抗氧化能力之间的相关性分析表明,总酚含量与总抗氧化能力之间存在显著线性相关,相关系数r达到0.9704,表明酚类物质是其抗氧化作用的主要物质基础。     

Antioxidant properties and total phenolics content of green and black tea under different brewing conditions

 The antioxidant activity and the total phenolics content of various tea extracts were analysed. Green and black tea were brewed from 0.5 min up to 10 min under different brewing conditions (stirring the extract, chopping the tea leaves before brewing). For measuring the antioxidant activity, the Trolox equivalent antioxidant capacity (TEAC) test and the low density lipoprotein (LDL) oxidation test were used. In all cases the antioxidant activity as well as the content of the phenolics increased with the brewing time. In black tea (brewed without stirring or chopping), the total phenolics increased from 33.8 mg/100 ml after 0.5 min up to 68.4 mg/100 ml after 10 min brewing time. Stirring during brewing led to higher phenolic yields in the extract. Thus, phenolics in stirred black tea ranged from 44.5 mg/100 ml (0.5 min) to 96.7 mg/100 ml (10 min). Chopping the tea leaves resulted in the highest content of phenolics. Antioxidant activity was well correlated with the corresponding total phenolics content. The results of the LDL oxidation test varied more than those of the TEAC test. Received: 27 May 1998 / Revised version: 15 July 1998