Screening of cereal varieties for antioxidant and radical scavenging properties applying various spectroscopic and thermoanalytical methods

Twenty varieties of four representative cereals, and sixteen varieties of six pseudocereals were investigated by different assays and analyses, covering the quantitative analysis of antioxidants, radical scavenging capacity (RSC) as well as total antioxidant capacity of cereals. The inter-variety variability in antioxidant capacity was determined by four independent methods for evaluation of antioxidant activity including 2,2'-azinobis-(3-ethylbenzthiazoline)-6-sulphonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrasyl (DPPH) tests, electron paramagnetic resonance (EPR)/spin-trapping assay and differential thermal analysis (DTA). The antioxidant capacity of studied samples determined in ABTS test ranged from 0.70 to 7.33 mg Trolox g⁻¹, in DPPH test from 1.31 to 54.79 mg Trolox g⁻¹and RSC values from EPR/spin-trapping assay varied from 0.27 to 13.52 mg Trolox g⁻¹ dry matter. The best antioxidant capacity was found for buckwheat ( Fagopyrum esculentum Moench), barley ( Hordeum vulgare L.) and Japanese millet ( Echinochloa frumentacea L.), where also the highest contents of total phenolics and exceptional thermal stability were observed.     

Effect of Lactic Acid Fermentation on Enrichment of Antioxidant Properties and Bioactive Isoflavones in Soybean

ABSTRACT: The antioxidant properties of 80% ethanolic extracts from soybean obtained with lactic acid fermentation using ABTS•⁺ [2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt] free radical decolorization assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay were measured, and the relationship between the observed antioxidant properties and the compositional changes in the isoflavone isomers was evaluated. Fermentation of soybean with 4 bacterial strains producing β-glucosidase for 48 h at 37°C— Lactobacillus plantarum KFRI 00144, Lactobacillus delbrueckii subsp. latisKFRI01181, Bifidobacteriathermophilum KFRI00748, and Bifidobacteria breve K-101—resulted in a significant increas (P < 0.05) in the antioxidant capacity expressed as Trolox equivalent antioxidant capacity (TEAC) (mM) and % scavenging activity. The significant bioconversion (P < 0.001) of the isoflavone glucosides (daidzin + genistin) into their responding bioactive aglycones (daidzein + genistein) during soy fermentation was observed. There was a good linear correlation between the concentration of isoflavone aglycones and the scavenging activity of ABTS ( R = 0.9045) assay, and DPPH ( R = 0.8299) assay in each extract. Among each extract, B. thermophilum KFRI 00748 showed a particularly high antioxidant activity (19.8 mM TEAC) and increased by 4.1 times compared with that of the control (4.8 mM TEAC), which fermented without strains. These results indicated that fermented soybean could be regarded as a potent antioxidant and radical scavenging dietary source due to their remarkable content of bioactive isoflavones.     

无梗五加叶体外抗氧化活性研究

研究无梗五加叶及其不同部分的抗氧化活性,研究其作为食用天然抗氧化剂的可行性.采用DPPH·、ABTS·+自由基及还原性反应体系,利用分光光度法测定无梗五加叶总提液及其不同组分在不同浓度下的抗氧化能力和总酚含量.结果表明:无梗五加叶的不同部分对DPPH·、ABTS·+自由基均具有较强的清除能力,对Fe3+有较强的还原能力...     

东北6 种红树莓叶酚类化合物的鉴定及抗氧化活性分析

以东北地区6 种不同品种的红树莓营养叶片为原料,采用分光光度法测定总酚、总黄酮和原花青素含量;使用3 种方法评价体外抗氧化活性并分析抗氧化活性与总酚、总黄酮和原花青素含量的相关性;采用超高效液相色谱-串联质谱法鉴定多酚类物质。结果表明,6 种红树莓叶片总酚含量高于总黄酮与原花青素含量。欧洲红的总酚与总黄酮含量最高,分别为（5.56±0.06）mg/g和（3.77±0.06）mg/g;哈瑞泰兹的原花青素含量最高为（3.06±0.04）mg/g。3 种抗氧化能力评价方法中,红树莓叶提取物对2,2’-联氮-双-(3-乙基苯并噻唑啉-6-磺酸二铵盐)（2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonate),ABTS）阳离子自由基清除能力与1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力具有极显著正相关性,相关系数为0.992;红树莓叶提取物中总酚含量和对ABTS阳离子自由基清除能力与对DPPH自由基清除能力的相关性显著,相关系数分别为0.886和0.891。超高效液相色谱-串联质谱法检出红树莓叶提取物中的13 种多酚类物质,其中有6 种酚酸和7 种类黄酮,主要酚酸为鞣花酸、绿原酸、没食子酸等;主要类黄酮为芦丁、儿茶素、表儿茶素、金丝桃苷等。     

Radical scavenging and antimicrobial activity of horsetail (Equisetum arvense L.) extracts

A reversed-phase high performance liquid chromatography (RP-HPLC) separation on C₈ column and quantitative method were developed to analyse hydroxyl derivatives of benzoic and cinnamic acid and flavonoids in horsetail ( Equisetum arvense L.) extracts. Total phenolic content of n -butanol, ethyl acetate and water extracts, determined by the Folin-Ciocalteu method, was 96.4, 26.4 and 15.4 mg g⁻¹ of dry extracts, respectively. The antioxidative activity of horsetail extracts was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reactive hydroxyl radicals by electron spin resonance spectroscopy. The results demonstrated that the free radical scavenging activity (versus both DPPH and hydroxyl radicals) depended on the type and concentration of applied extracts; the highest DPPH (EC₅₀ = 0.65 mg mL⁻¹) and hydroxyl radical scavenging activities (EC₅₀ = 0.74 mg mL⁻¹) were obtained in the case of n -butanol extract. The radical scavenging activity of extracts significantly correlated with total phenolic content. The antimicrobial tests showed that ethyl acetate and n -butanol extracts inhibited the growth of tested bacteria.     

Singlet Oxygen Quenching Activities of Various Fruit and Vegetable Juices and Protective Effects of Apple and Pear Juices against Hematolysis and Protein Oxidation Induced by Methylene Blue Photosensitization

ABSTRACT:  Effects of various fruit and vegetable juices on rubrene oxidation induced by a chemical source of singlet oxygen in a microemulsion system have been studied. The singlet oxygen quenching activities of fruit and vegetable juices were greatly different with different juices. The apple and pear juices exhibited the highest antioxidative activity among the tested juices in singlet oxygen–induced rubrene oxidation, showing 56.69% and 59.34% inhibition, respectively. The grape, kumquat, red cabbage, and spinach juices also showed relatively strong antioxidative activity against singlet oxygen–induced rubrene oxidation. Lemon juice showed the least activity, resulting in 0.63% inhibition of rubrene oxidation. The singlet oxygen quenching activities of 1 mL of apple and pear juices were equivalent to 33.97 and 34.64 mg ascorbate, respectively. Singlet oxygen quenching activities of juices had very low correlation with both ABTS radical scavenging activity ( R ²= 0.11) and total phenolic contents ( R ² < 0.1). However, a high correlation ( R ²= 0.66) was found between the ABTS radical scavenging activities and total phenolic contents of juices. The apple and pear juices also significantly inhibited both erythrocyte lysis and protein oxidation induced by fluorescence light illumination in the presence of methylene blue. Electron spin resonance (ESR) spectroscopy data showed that the protective activities of these juices against biological damages induced by photodynamic ways were, to at least some extent, due to their singlet oxygen quenching abilities. This represents first report on the singlet oxygen quenching activities of the apple and pear juices, and their protective activities against photodynamically induced biological damages.     

Antioxidant Properties of Edible Basidiomycete Phellinus igniarius in Submerged Cultures

ABSTRACT:  Dried mycelia and mycelia-free broths produced by submerged cultures of  Phellinus igniarius  under optimal culture conditions were extracted using methanol and hot water and investigated for antioxidant properties. Methanolic extracts from dried mycelia (MEM) and mycelia-free broth (MEB) showed significant antioxidant properties for all EC₅₀ values less than 10 mg/mL except for MEB in scavenging effects on DPPH radicals. Hot water extracts from dried mycelia (HWEM) were evidenced by their low EC₅₀ values (<10 mg/mL) to be effective in reducing power, chelating effect on ferrous ions, and scavenging effect on superoxide anions. α-tocopherol was mainly found in MEM and γ-tocopherol in MEB. Ascorbic acid and total flavonoids were abundant in methanolic extracts (MEM + MEB), whereas total phenols were rich in HWEM. An excellent correlation between contents of total phenols and EC₅₀ values was accomplished for antioxidant activity ( R ²= 0.996) and chelating ferrous ions ability ( R ²= 0.922).
Practical Application: In our paper, the products by submerged culture of  Phellinus igniarius  exhibited powerful antioxidant properties. Results told that extracts from fermenting products by  P. igniarius  might be good sources for antioxidant-related functional foods and pharmaceutical industries.     

体外模拟胃肠消化对古茶树叶酵素中活性成分和抗氧化活性的影响

为探究古茶树叶酵素经模拟胃、肠消化后活性成分和抗氧化活性的变化,该研究采用体外模拟胃、肠消化的方法,检测古茶树叶酵素模拟胃肠消化过程中总酚、黄酮、原花青素含量的释放规律,同时对模拟胃肠消化前后茶叶酵素中的5种儿茶素类物质含量变化进行了分析,并对其体外抗氧化活性的变化规律进行了进一步研究。结果表明:古茶树叶酵素在模拟胃消化中,总酚、总黄酮含量和ABTS阳离子自由基清除能力、还原力均显著提高（P<0.05）,原花青素含量、DPPH自由基清除能力无显著变化（P>0.05）;在模拟肠消化中,总酚含量、ABTS阳离子自由基清除能力显著提高（P<0.05）,总黄酮含量、DPPH自由基清除能力、还原力无显著变化（P>0.05）,原花青素含量显著降低（P<0.05）。5种儿茶素类物质中在胃消化过程中无显著性变化（P>0.05）,而在肠消化过程中均显著下降（P<0.05）,儿茶素、表没食子儿茶素、表儿茶素、表儿茶素没食子酸酯含量在模拟肠消化2 h后分别下降了74.58%、64.40%、86.95%、48.21%。这表明,古茶树叶酵素在模拟胃肠消化过程中,胃蛋白酶、胃酸可促进抗氧化活性物质释放,有较好的抗氧化活性,有望应用于抗氧化产品的开发。     

赤霞珠葡萄籽多酚低共熔溶剂提取及其抗氧化活性研究

研究不同绿色低共熔溶剂（DESs）结合超声辅助对赤霞珠葡萄皮渣中葡萄籽多酚提取及提取物体外抗氧化活性的影响。结果表明,部分DESs对总酚及总黄酮的提取量显著优于传统提取溶剂（水、体积分数为80%乙醇、体积分数为80%甲醇）（P＜0.05）。提取总酚和总黄酮最优的DESs分别为氯化胆碱-乳酸和脯氨酸-乙酰丙酸。绝大部分DESs提取物中单体酚的含量显著高于传统提取溶剂（P＜0.05）。氯化胆碱-乙二醇提取物DPPH自由基清除能力最强,脯氨酸-乙二醇提取物ABTS+自由基清除能力最强,均显著高于传统溶剂提取物（P＜0.05）。皮尔森相关性分析结果表明,赤霞珠葡萄籽DESs提取物中总酚、儿茶素、表儿茶素含量与其体外抗氧化能力呈显著正相关（P＜0.05）。     

不同品种苹果非浓缩还原汁的多酚组成及与抗氧化能力的关系

目的:通过分析15种非浓缩还原(NFC)苹果汁的多酚组成、抗氧化能力及二者相关性,研究多酚组成对抗氧化能力的贡献,为果汁生产企业在原料果选择方面提供借鉴。方法:制备15个品种的NFC苹果汁,利用超高效液相色谱(UPLC)和体外抗氧化试验分析多酚组成和抗氧化能力(DPPH和ABTS自由基清除能力),通过单因素方差和相关性分析处理试验结果。结果:NFC苹果汁中,单体酚以绿原酸含量最高,表儿茶素没食子酸酯含量最低;大类多酚有原花青素、酚酸和黄酮类3种,其中酚酸含量最高(102~331μg/mL),黄酮含量最低(5~30μg/mL)。不同品种苹果中,“乔纳金”苹果的DPPH自由基清除能力最高为89.1%,“秋香”苹果的ABTS自由基清除能力最强为92.6%。结论:原花青素大类物质是NFC苹果汁体外抗氧化能力的主要贡献者,原花青素B2、表儿茶素和表儿茶素没食子酸酯3种单体酚有较强的DPPH自由基清除能力,而ABTS自由基清除能力更多地依赖于总酚含量。     

Determination of Anthocyanins, Total Phenolic Content, and Antioxidant Activity in Andes Berry (Rubus glaucus Benth)

ABSTRACT:  Anthocyanins, total phenolic content, ascorbic acid content, and the antioxidant activity were determined in extracts of Andes berry fruit ( Rubus glaucus Benth). Anthocyanis (ACNs) were isolated and characterized by means of high-performance liquid chromatography (HPLC) with photodiode array detection and electro spray ionization/mass spectrometry (PDA-ESI/MS/MS) analysis. The anthocyanin (ACN) content was 45 mg/100 g FW. The isolated anthocyanins were characterized as cyanidin 3-sambubioside, cyanidin 3-glucoside, cyanidin 3-xylorutinoside, cyanidin 3-rutinoside, pelargonidin 3-glucoside, and pelargonidin 3-rutinoside. The ascorbic acid content was 10.1 mg/100 g FW. The total phenolic content as determined by the Folin–Ciocalteau method was 294 mg GAE/100 g FW while the antioxidant activity as measured by ABTS ^{· +} radical scavenging capacity and ferric reducing antioxidant power (FRAP) was 2.01 and 4.50 mmol TE/100 g FW or 8.22 mmoles ferric iron reduced/100 g FW, respectively. The high phenolic content and antioxidant capacity of Andes berry suggest that this fruit could be a rich source of natural pigments, nutraceuticals, and natural antioxidants.     

3 种梨果实发育过程中酚类物质及其抗氧化能力分析

为进一步了解新疆主要栽培品种梨生长发育期果实酚类物质和抗氧化能力的变化规律,选取‘库尔勒香梨’‘早酥梨’及其杂交后代‘新梨7号’果实为试材,对其总酚、总黄酮、酚类物质含量以及1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力和2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）阳离子自由基清除能力进行分析。结果表明：3 种梨果实总酚含量、总黄酮含量、DPPH自由基清除能力在整个生长发育过程中总体呈逐渐降低的变化趋势,ABTS阳离子自由基清除能力呈先降低后升高再降低的变化趋势,花后50 d‘早酥梨’果实中总酚和总黄酮含量、DPPH自由基清除能力最高,分别达23.10、32.25 mg/g和29.12 μmol/g;花后80 d,‘早酥梨’果实ABTS阳离子自由基清除能力最高,达80.74 μmol/g。不同生长发育期同品种梨果实的酚类物质含量均存在明显差异,果实中的熊果苷、儿茶素、绿原酸、表儿茶素、槲皮葡萄糖苷、山柰酚-3-O-葡萄糖苷含量总体逐渐降低,其中熊果苷含量最高,平均值为5 797.82 μg/g,其次是绿原酸含量,平均值为1 781.02 μg/g。梨果实中总黄酮、总酚、熊果苷、儿茶素、绿原酸、表儿茶素含量与DPPH自由基清除能力呈极显著正相关（P＜0.01）。3 种梨幼果期（花后50 d）酚类物质及抗氧化能力较高,‘早酥梨’总酚含量、总黄酮含量、DPPH自由基清除能力和ABTS阳离子自由基清除能力均比‘库尔勒香梨’和‘新梨7号’高。     

油茶籽油不同形态酚类化合物的抗氧化互作关系

本研究首先对油茶籽油中游离酚（free phenolics，FP）、酯化酚（esterified phenolics，EP）及不溶性结合酚（insoluble-bound phenolics，ISP）含量及主要物质组成进行分析，并通过测定铁离子还原能力、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力、1,1-二苯基-2-三硝基苯肼自由基清除能力及β-胡萝卜素漂白能力对其中FP、EP及ISP的抗氧化活性及互作关系进行研究。结果表明，油茶籽油总酚含量为（137.97±5.14）mg/kg，其中ISP含量显著高于FP及EP（P＜0.05），占油茶籽油总酚的47.74%。另外，FP中以苯甲酸衍生物含量较高（主要为异香兰素及甲基香兰素），EP中主要为水杨酸，ISP中主要为3,4-二羟基扁桃酸。3 种形态酚类化合物在不同机制下的抗氧化能力不同，且呈现质量浓度依赖效应。FP＋ISP组合及EP＋ISP组合在抗氧化互作方面表现出一定的协同或相加作用，且后者复配组合的抗氧化活性更强；而FP＋EP组合和FP＋EP＋ISP组合则表现出拮抗或相加作用。     

干燥方式对无花果酚类物质及其抗氧化活性的影响

研究自然晒干、真空冷冻干燥、烘箱干燥、远红外干燥和真空干燥对无花果总酚含量、酚类物质组成及其 体外抗氧化活性的影响。采用福林-酚比色法及高效液相色谱法分别测定干燥后无花果的总酚含量和酚类物质的组 成,并比较多酚提取液对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picryhydrazyl,DPPH）自由基清除能力、2,2’-联 氨-双-（3-乙基苯并噻唑啉-6-磺酸）二铵盐（2,2’-azino-bis-(3-ehtybenzothiaazoline-6-sulfonic acid) diammonium salt, ABTS）自由基清除能力和总还原力的影响,采用统计学方法分析酚类物质含量与其抗氧化活性的相关性。结果表 明：经不同方式干燥后无花果的总酚含量、各酚类物质含量均有显著性差异（P＜0.05）,其中真空干燥后样品的 总酚含量与酚类物质含量总和均为最高;不同干燥方式对无花果的抗氧化活性影响显著（P＜0.05）,真空干燥样 品的DPPH自由基清除能力、ABTS＋·清除能力和总还原力均为最高,且相关性分析结果显示,无花果抗氧化活性 与儿茶素、槲皮苷、阿魏酸、4-羟基苯甲酸等酚类物质的含量之间呈显著相关（P＜0.05）。综上,真空干燥处理 后无花果总酚含量及多酚各组分含量总和最多、抗氧化活性最强,适宜于无花果的干燥。     

厚朴籽不同溶剂萃取物抗氧化活性比较分析

为研究厚朴籽抗氧化成分,测定厚朴籽90%乙醇粗提物及其石油醚、乙酸乙酯、正丁醇和水萃取物的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除活性,2,2-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(2,2-azino-bis(3-ethylbenzthiazoline-6-sulonic acid),ABTS)自由基清除活性和铁离子还原能力(ferric reducing antioxidant power,FRAP),同时测定其总酚及总黄酮含量。结果发现,乙酸乙酯萃取物的总酚和总黄酮的含量最高,含量依次为(253.64±7.25)和(179.11±0.61)mg/g。厚朴籽乙醇粗提物和萃取物具有一定抗氧化活性,其中乙酸乙酯萃取物的抗氧化活性最强,DPPH自由基清除活性显著(P<0.05)高于阳性对照BHT,其IC₅₀仅为(29.33±2.31)μg/mL;乙酸乙酯萃取物ABTS自由基清除活性与V_C相当,IC₅₀分别(30.33±1.53)和(31.67±3.06)μg/mL;厚朴籽乙醇粗提物和萃取物对铁离子的还原能力较低,均显著(P<0.05)低于阳性对照V_C和BHT。相关性显示,厚朴籽三种体外抗氧化活性均与总酚和总黄酮极显著相关(P<0.01)。以上结果表明,乙酸乙酯可以富集厚朴籽酚类物质,为下一步厚朴籽抗氧化物质分离奠定了理论依据。     

贮藏及消化对蓝莓酸奶中酚类物质稳定性及抗氧化活性影响

为研究蓝莓酸奶在贮藏及消化时酸奶中多酚类物质的稳定性及抗氧化活性,以总酚、总黄酮和花色苷含量为 多酚类物质稳定性指标,以总抗氧化活力、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）和2,2-联 氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐（2,2′-azino-bis(3-ethylbenzthiozoline-6)-sulphonic acid,ABTS）自由基清 除能力为抗氧化指标,测定其在4 ℃贮藏21 d和体外消化时各指标变化情况。结果表明：贮藏初期,蓝莓酸奶中 总酚、总黄酮、花色苷含量分别为46.14、41.63、9.01 mg/100 g提取样,总抗氧化活力、DPPH自由基清除能力、 ABTS＋?清除能力分别为44.51、59.49、61.39 mg/100 g提取样,贮藏期结束时各酚类物质含量分别降低了10.20%、 9.86%、15.54%,各抗氧化指标分别降低了6.52%、7.23%、6.03%,降幅均高于蓝莓果料（1.93%、3.46%、0.03%和 3.58%、4.17%、4.91%）,说明酸奶体系降低了多酚类物质的稳定性和抗氧化活性。消化前,蓝莓酸奶的各指标均低于 蓝莓果料,体外消化后,蓝莓酸奶除总黄酮含量、DPPH自由基清除能力低于蓝莓果料外,总酚、花色苷含量、总抗氧 化活力及ABTS＋?清除能力均高于蓝莓果料,说明蓝莓酸奶经胃肠消化后其多酚类物质被释放,抗氧化活性增强。     

红景天和轮叶党参混合提取物戊糖乳杆菌发酵条件及抗氧化作用分析

目的：优化红景天和轮叶党参混合提取物（mixed extracts from Rhodiola sachalinensis and Codonopsis lanceolata,RCME）戊糖乳杆菌发酵条件,分析发酵产物的主要活性成分组成与含量,评价其抗氧化作用。方法：RCME中接种戊糖乳杆菌,以发酵液中的pH值、总酸含量及生物量为指标,研究发酵所需的最佳时间、培养基组成（红景天和轮叶党参混合比例）、RCME最佳质量浓度;采用比色法测定RCME发酵前后的总蛋白质、中性糖、酸性多糖及总酚含量变化,采用高效液相色谱法分析RCME发酵前后的红景天苷和酪醇含量变化,采用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和2,2’-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐自由基（2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt radical,ABTS＋·）清除实验评价RCME发酵物的抗氧化作用。结果：单纯红景天提取物发酵24～72?h,其pH值和总酸含量无明显变化,随着发酵时间延长,乳杆菌数明显减少（P＜0.01）。红景天和轮叶党参混合质量比达到3∶2,发酵24h后发酵液的pH值下降幅度和总酸含量升高的幅度最大,发酵48?h时后,pH值和总酸含量无明显的变化,乳杆菌数有所减少。可溶性固形物质量分数在1.0%～3.0%范围内,红景天苷转化为酪醇的转化率无明显差异。RCME发酵24?h后,红景天苷含量显著减少（P＜0.01）,酸性多糖、总酚、蛋白质及酪醇含量均显著增加（P＜0.05或P＜0.01）。RCME发酵后DPPH自由基和ABTS＋·清除能力明显增强。结论：RCME发酵条件为红景天-轮叶党参混合比例3∶2、可溶性固形物质量分数1.0%～3.0%、发酵时间24?h。     

Comparative antioxidant activity of edible Japanese brown seaweeds

Japanese edible brown seaweeds, Eisenia bicyclis (Arame), Kjellmaniella crassifolia (Gagome), Alaria crassifolia (Chigaiso), Sargassum horneri (Akamoku), and Cystoseira hakodatensis (Uganomoku) were assayed for total phenolic content (TPC), fucoxanthin content, radical scavenging activities (DPPH, peroxyl radical, ABTS, and nitric oxide), and antioxidant activity in a liposome system. Among the solvents used for extraction, methanol was the most effective to extract total phenolics (TPC) from brown seaweeds. Among 5 kinds of brown seaweeds analyzed, methanol extract from C. hakodatensis was the best source for antioxidants. The high antioxidant activity of the extract was based not only on the high content of phenolics, but on the presence of fucoxanthin. No significant correlation (P > 0.05) was observed between TPC per gram extract with DPPH radical scavenging activity of the methanol extracts. These observed discrepancy would be due to structural variations in the phenolic compounds, and different levels of fucoxanthin in the extracts. The present study also demonstrated the synergy in the antioxidant activity of the combination of brown seaweed phenolics and fucoxanthin.     

中早熟苹果品种的贮藏品质和酚类物质差异分析

中早熟苹果品种可以丰富水果市场,是苹果产业重要的组成部分,研究其贮藏特性及品质差异意义重大。本实验以‘鲁丽’‘鲁艳’两个苹果新品种为研究对象,以其亲本‘嘎啦’为参照,探究3种苹果的贮藏品质和酚类物质差异。结果表明：相比于‘嘎啦’苹果,‘鲁丽’苹果可溶性固形物质量分数最高,果皮a*值最大,外观品质最佳、适于鲜食,而‘鲁艳’苹果总酸度高、固酸比低,贮藏期间乙烯释放量高,不耐贮藏。与‘嘎啦’和‘鲁艳’苹果相比,‘鲁丽’苹果有着最高的总酚、总黄酮含量和1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率,抗氧化能力最强。3种苹果主要的酚类物质也因品种、成熟度和果实部位存在差异,‘嘎啦’和‘鲁丽’苹果果肉均以绿原酸含量最高,而‘鲁艳’苹果表儿茶素含量最高,果皮酚类物质含量高于果肉。相关性和主成分分析表明果实硬度与a*值有高度显著负相关性（P<0.001）,可溶性固形物质量分数与总酚、总黄酮、绿原酸含量和DPPH自由基清除率存在高度显著正相关（P<0.001）,主成分1主要由总酚、总黄酮、绿原酸、表儿茶素含量等指标决定,成熟...