不同比例的α-生育酚及α-生育三烯酚抗氧化能力的比较

为了探究不同比例的α-生育酚及α-生育三烯酚抗氧化能力的大小，共开展2个试验。试验一∶设置4个不同比例的α-生育酚及α-生育三烯酚，分别为α-生育酚(TE组)、α-生育酚∶α-生育三烯酚=6.5∶1(TT1组)、α-生育酚∶α-生育三烯酚=2.75∶1(TT2组)、α-生育酚∶α-生育三烯酚=1.5∶1(TT3组),生育酚及生育三烯酚之和均为100μmol/L,测定其羟自由基清除率、超氧阴离子清除率。试验二∶选用与试验一相同比例的α-生育酚及α-生育三烯酚，与猪小肠上皮细胞(IPEC-J2)共培养6 h后加入敌草快(Diquat, DQ)处理4 h,用CCK-8法测定细胞活力，用流式细胞仪测定细胞内活性氧含量。试验结果表明∶不同比例的α-生育酚与α-生育三烯酚对羟自由基的清除率存在差异，其中TT3组羟自由基清除率显著高于TE组(P<0.05),其余各组间无显著性差异；超氧阴离子清除率也受α-生育酚与α-生育三烯酚比例的影响，TT1组超氧阴离子清除率显著高于TE组(P<0.05),TT2、TT3组极显著高于TE组(P<0.01)。细胞培养试验表明∶敌草快处理后极显著降低...     

顶孢霉发酵液提取物清除自由基能力的研究

为了研究筛选出的具有抗氧化活性的2株顶孢霉的发酵液提取物清除自由基的能力,本研究制备了2株顶孢霉的发酵液提取物,比较了其清除O2-·、·OH和DPPH·三种自由基的能力.结果表明:2株顶孢霉发酵液提取物的相对还原力(即总抗氧化活性)均显著高于维生素E;对O2-·自由基的清除率也均高于维生素E,其中,菌株YX015更为高效,在1.0mg/mL浓度时对O2-·自由基的清除率达到49.15%;2菌株清除·OH和DPPH·的能力均显著弱于维生素E,但都高于其自身清除O2-·的能力,在浓度达到1.0mg/mL时,菌株CA022对·OH的清除率为60.43%;菌株YX015对·OH的清除率为83.33%.     

三孢布拉霉产β-胡萝卜素的抗氧化活性动力学研究

β-胡萝卜素具有较强的抗氧化活性,三孢布拉霉(Blakeslea trispora)是β-胡萝卜素的高产菌株。以发酵三孢布拉霉菌株提取的β-胡萝卜素为研究对象,采用DPPH(对1,1-二苯基-2-三硝基苯肼,1,1-diphenyl-2-picrylhydrazyl)法,测定自由基清除率,对β-胡萝卜素抗氧化活性进行研究。考察在不同温度下,不同浓度的β-胡萝卜素抗氧化活性的不同,计算了相关动力学数据:活性半数效应浓度(EC_(50))、表观活化能(Ea)和反应速率常数(k)。结果表明,相同浓度下,β-胡萝卜素在37℃抗氧化活性达到平衡的时间为30 min,短于25℃时45 min的平衡时间,说明温度越高,反应速度越快;在相同温度下,β-胡萝卜素浓度越高,抗氧化活性越强,当浓度达到160μg/m L时,达到70.77%的清除效率。同时,通过计算可得,随反应温度的升高,反应速率常数k增大,说明反应温度对β-胡萝卜素抗氧化活性有较大影响,但不同质量浓度的Ea稳定在31 k J/mol左右,没有显著性差异,说明起始浓度对活性没有影响。     

电子顺磁共振波谱法测定三种类胡萝卜素抗氧化活性

运用电子顺磁共振波谱(EPR),通过三种类胡萝卜素(番茄红素、叶黄素、β-胡萝卜素)对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)和羟基自由基(·OH)清除能力大小的比较,测定了三种类胡萝卜素抗氧化活性能力。结果表明,DPPH和Fe2+(固定Fe2+:H₂O₂=1:10)浓度均与EPR信号呈良好的线性关系,相关系数R2均大于0.99。三种类胡萝卜素对DPPH·和·OH均有一定清除作用,且随浓度的增大和时间的延长清除作用逐渐增强。其中,番茄红素的抗氧化活性能力最强,叶黄素次之,β-胡萝卜素最弱,浓度为0.6 mmol/L的番茄红素、叶黄素和β-胡萝卜素对DPPH·的清除率分别为95.4%、76.7%和47.7%,对·OH的清除率分别为56.6%、29.1%和14.0%。相较于紫外-可见分光光度(UV-Vis)法,该方法可以有效避免类胡萝卜素自身颜色对测试结果的干扰,研究结果可为完善类胡萝卜素等天然食品添加剂的抗氧化能力评价方法提供依据。     

两种生育酚酯衍生物对D-半乳糖致衰老小鼠的抗衰老作用

为探究两种生育酚酯衍生物（D-α-生育酚醋酸酯和DL-α-生育酚醋酸酯）的抗衰老作用,本实验测定其体外抗氧化能力,并采用D-半乳糖构建衰老小鼠模型,同时用两种生育酚酯衍生物干预42 d,分析衰老相关指标变化规律。结果表明：在0.1～0.3 mg/mL质量浓度范围内,两种生育酚酯衍生物的羟自由基清除能力、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、Fe2+螯合能力、总还原能力均优于VC。与衰老模型组相比,经过生育酚酯衍生物干预后,小鼠血清中丙二醛含量显著下降（P<0.05,P<0.01,P<0.001,P<0.000 1）,谷胱甘肽过氧化物酶和总抗氧化能力显著升高（P<0.05,P<0.01,P<0.001,P<0.000 1）;血清中炎症因子白细胞介素-6、白细胞介素-1β、肿瘤坏死因子-α和肝功能指标天冬氨酸氨基转移酶、丙氨酸氨基转移酶水平显著降低（P<0.05,P<0.01,P<0.001,P<0.000 1）;小鼠肝脏中核因子-E2-相关因子（nuclear factor E2 re...     

核桃油微量组分对其氧化稳定性的影响

测定核桃油对DPPH·、ABTS+·的清除能力,结合β-胡萝卜素脱色法,评价核桃油体外抗氧化能力。通过相关性分析、回归分析评价核桃油中共轭烯烃、羰基化合物、多酚、生育酚、黄酮、β-胡萝卜素及磷脂对核桃油氧化稳定性的影响。结果表明:核桃油具有一定的体外抗氧化活性,对DPPH·和ABTS+·的半抑制浓度(IC50)分别为0.161 g/m L和0.841 g/m L,通过β-胡萝卜素脱色法测得的核桃油抗氧化半抑制浓度(IC50)为1.292 g/m L,且核桃油体外抗氧化活性与其OSI显著相关(P<0.05)。同时发现,核桃油中7种微量组分含量与其OSI有显著相关性(P<0.05),其相关程度依次为:生育酚>总酚>黄酮>共轭烯烃>羰基化合物>β-胡萝卜素>磷脂,且抑制初级氧化的能力为:生育酚>β-胡萝卜素>黄酮>总酚>磷脂,而抑制次级氧化的能力:总酚>生育酚>黄酮>磷脂>β-胡萝卜素。     

不同提取方法的野马追提取物抗氧化作用的比较研究

以野马追干制品为原料,利用6种不同的提取方法得到粗提物,分别利用FRAP法、ABTS法、超氧阴离子自由基清除法、总还原力法、羟自由基清除法、抗脂质体过氧化法对抗氧化活性进行测定比较,其中以BHT和BHA为阳性对照。除抗脂质体过氧化活性以外,6种提取方法得到的粗提物均表现出较强的抗氧化活性,但不同方法粗提物的具体抗氧化活性指标差异显著。水煎物清除羟自由基的作用最明显,清除率为96.97%(P<0.05)。70%乙醇回流法提取物对超氧阴离子自由基的清除作用最明显,清除率高达87.70%(P<0.05)。渣提物的总还原能力最强(P<0.05)。六种提取物都具有高于BHT和BHA的ABTS+.清除能力,其中70%乙醇回流法和浸提法粗提物无显著性差异。     

不同品种枣果活性成分及抗氧化特性比较

采用高效液相色谱仪对我国6种枣果中多酚物质、三萜酸、环核苷酸、VC、α-生育酚与β-胡萝卜素的含量进行测定,比较其抗氧化能力,探究枣果抗氧化能力与抗氧化物之间的相关性。结果表明:不同品种枣果的上述活性物质含量存在较大差异,木枣的总酚、总黄酮、单酚类物质(儿茶素、表儿茶素、芦丁、香草酸、咖啡酸和丁香酸)含量均最高,枣果的总酚与其FRAP值及清除ABTS·+能力显著相关,丁香酸含量与清除·DPPH能力存在显著相关,而其余酚类物质均与枣果的抗氧化特性不存在显著相关性;哈密大枣中α-生育酚、β-胡萝卜素、c AMP含量均显著高于其余枣果;金丝小枣中c GMP含量显著高于其余5种枣果;除梨枣外,其余枣果的桦木酸含量最高,齐墩果酸次之,熊果酸含量最低。     

膳食结构对柑橘类胡萝卜素生物利用度和抗氧化活性的影响

为探究不同膳食结构（正常膳食、高蛋白膳食、高脂膳食和高糖膳食）对柑橘类胡萝卜素生物利用度和抗氧化活性的影响,本实验通过模拟体外消化,对柑橘消化过程中类胡萝卜素含量、铁离子还原力、1,1-二苯基-2-苦基肼自由基清除能力和2,2’-联氨-双-(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力等变化进行监测,并进行类胡萝卜素含量和抗氧化活性变化相关性分析。结果显示,随着消化的进行,各膳食结构组中总类胡萝卜素含量及其两种类胡萝卜素单体含量均呈不断下降的趋势,同时各膳食结构组的类胡萝卜素抗氧化能力也显著下降（P<0.05）。4种膳食结构中,高脂膳食组的类胡萝卜素在不同消化阶段均保持较高含量,同时其在不同消化阶段的抗氧化能力也较强。相关性研究发现,柑橘类胡萝卜素的抗氧化活性与其含量之间呈显著正相关（P<0.05）。综合分析可知,膳食结构对柑橘类萝卜素生物利用度和抗氧化活性影响较大,高脂膳食组的类胡萝卜素生物利用度（（24.08±1.78）%）显著高于正常膳食组（（19.26±1.06）%）(P<0.05),其抗氧化活性也最强,高蛋白膳食组的类胡萝卜素生物利用度（（15.27±...     

多肽体外抗氧化活性测定方法的比较

为确定适用于多肽体外抗氧化活性的测定方法,以丁基羟基茴香醚（butyl hydroxylanisole,BHA）、VC和生育酚（vitamin E,VE）为对照,测定大豆肽的还原能力、螯合Fe2＋能力、清除2,2’-联氮双（3-乙基苯并噻唑啉-6-磺酸）二胺盐（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt,ABTS）自由基和1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基及抑制脂质体氧化的活性。结果显示：在质量浓度为0～30 mg/mL时,大豆肽还原能力随质量浓度的增加而增强,与BHA、VE、VC类似,大豆肽最大还原能力仅为0.487。大豆肽抑制脂质体氧化的活性弱于BHA和VE,但具有较稳定的增加趋势,最大抑制率达到20.6%;在质量浓度为0～15 mg/mL时,大豆肽螯合Fe2＋能力随质量浓度的增加而增强,最大螯合率为38.7%。然而,未检测出BHA、VE、VC具有螯合Fe2＋的能力;在质量浓度为0～3.0 mg/mL时,大豆肽清除ABTS＋·活性与VC基本相同,大于BHA和VE,ABTS＋·清除率最大为61.2%。大豆肽DPPH自由基清除率最大仅为2.1%,清除DPPH自由基活性远低于VC（45.0%）、BHA（10.1%）和VE（10.7%）,表明螯合Fe2+能力、清除ABTS＋·及抑制脂质体氧化活性的测定方法适合用于评价大豆肽体外抗氧化活性。     

Antioxidant activity of tomato lipophilic extracts and interactions between carotenoids and α-tocopherol in synthetic mixtures

In the present study we assayed the antioxidant activity of lipophilic extracts obtained from different tomato varieties. The results showed that cherry tomatoes, characterized by a high carotenoid content, had the highest antioxidant activity. A quantitative analysis of lycopene, β-carotene, lutein and α-tocopherol was also performed and the correlation between the antioxidant content and the antioxidant activity was estimated. The highest correlation coefficient was found for lycopene (R² = 0.9236, P ≤ 0.001). The analysis of two-component mixtures containing α-tocopherol and carotenoids showed that significant synergism occurred for all the combinations which contained α-tocopherol and β-carotene mixed together. The highest synergistic effects were detected for α-tocopherol-lycopene mixtures, which were the most efficient combinations tested in the present study. The analysis of the carotenoid combinations indicated that synergism occurred for lycopene-β-carotene, lycopene-lutein and lutein-β-carotene mixtures. The analysis of four-component mixtures did not show statistically significant synergistic effects.     

Determination of antioxidant activity and antioxidant content in tomato varieties and evaluation of mutual interactions between antioxidants

Major antioxidants and antioxidant activity in eight varieties of tomatoes were determined. Hydrophilic and lipophilic antioxidant activity (HAA and LAA) was determined by the ABTS assay and ascorbic acid and carotenoid contents were determined by HPLC-DAD. The HAA has far more significant impact on total antioxidant activity (83%) as compared with LAA. HAA was increasing during all ripening stages and was strongly correlated with ascorbic acid content (r = 0.83). During the ripening the LAA was increasing till the III. stage of maturity and then decreased. The main carotenoids determined in the red-fruit tomatoes were lycopene, β-carotene and lutein. The content of lycopene has been increasing equally during the ripening. β-Carotene and lutein were intensively synthesized between the I. and II. stage of maturity. Among ascorbic acid, α-tocopherol, lycopene, β-carotene and lutein standards ascorbic acid was determined as the most efficient antioxidant followed by α-tocopherol and β-carotene. Antioxidant activity of ascorbic acid, α-tocopherol, β-carotene and lutein grew equally with increasing concentration, however lycopene was the most effective in its lowest concentration. The analysis of two-component mixtures showed significant synergism between lycopene-lutein, lycopene-β-carotene and α-tocopherol-β-carotene.     

Effect of adding ascorbic acid and glucose on the antioxidative properties during storage of dried carrot

In this study, carrots were treated with ascorbic acid (0.1%) in a glucose (1.0%) solution (AA-Glu), and then freeze-dried and hot-air-dried to investigate the effects on their antioxidant content after 30 days of storage. The antioxidant components were extracted from the carrot samples using methanol. To assess antioxidative properties, tests measured the samples’ reducing power, α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, and ferrous ion chelating power. The above antioxidative properties of carrot extracts were compared with α-tocopherol and butylated hydroxyanisole (BHA). The analysis of antioxidant compounds included the total amount of ascorbic acid, total amount of phenolics, total amount of flavonoids, and carotenoids. The analysis showed that the samples immersed in AA-Glu solution prior to drying exhibited a higher antioxidative property than those not immersed.     

Determination of carotenoids in Dunaliella salina cultivated in Taiwan and antioxidant capacity of the algal carotenoid extract

A simple HPLC method with good separation efficiency was developed to determine all-trans and cis forms of carotenoids in Dunaliella salina cultivated in Taiwan. The analysis used a C30 column (250 × 4.6 mm, 5 μm) and an isocratic solvent system (flow rate = 1 mL/min) mixing methanol–acetonitrile–water (84/14/2, v/v/v) and methylene chloride, (75/25, v/v). Carotenoids were detected at 450 nm. Moreover, the antioxidant capacities of the algal carotenoid extract were also evaluated with Trolox equivalent antioxidant capacity (TEAC) assay, reducing power and 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical scavenging assay. Results showed that 7 carotenoids in the algal extract could be separated simultaneously within 30 min and the total amount of them was 290.77 mg/g algae. The contents of all-trans-β-carotene and 9- or 9′-cis-β-carotene, the major carotenoids in the algae, were 138.25 and 124.65 mg/g algae, respectively. The contents of all-trans-lutein, all-trans-zeaxanthin, 13- or 13′-cis-β-carotene, all-trans-α-carotene and 9- or 9′-cis-α-carotene were 6.55, 11.27, 4.95, 2.69, and 2.41 mg/g algae, respectively. The algal carotenoid extract had significantly higher antioxidant activity than all-trans forms of α-carotene, β-carotene, lutein and zeaxanthin in all antioxidant assays. The cis forms of carotenoids, especially 9- or 9′-cis-β-carotene, might play crucial roles for the antioxidant capacities of the algal extract.     

The effect of α-tocopherol and butylated hydroxyanisole on the colour properties and lipid oxidation of kavurma, a cooked meat product

Kavurma is a cooked meat product and is consumed sliced. The amount of animal fat in kavurma (30-40%) is higher than in other meat products; therefore, lipid oxidation and colour defects are a major problem during storage and in the market place. To preserve the quality characteristics of kavurma in markets antioxidants must be added and the product must be packaged and stored at low temperature. In this study, the effects of α-tocopherol and butylated hydroxyanisole (BHA) levels on lipid oxidation and colour deterioration of sliced and vacuum-packaged kavurma were investigated. Kavurma was made from beef meat and melted beef fat in 5 groups: No-added antioxidant, 50mg/kg BHA, 100mg/kg BHA, 50mg/kg α-tocopherol and 100mg/kg α-tocopherol. The kavurma produced was sliced (3-4-cm thick) and vacuum packed and stored at 4°C for 300 days, and thiobarbituric acid reactive substance, pH, moisture, lightness, redness and yellowness values of sliced product were determined during storage. The use of antioxidants in kavurma production caused a significant (P<0.01) decrease in the thiobarbituric acid reactive substances (TBARS) values. The lipid oxidative stability effect of the antioxidants was in following order: 100mg/kg BHA>100mg/kg α-tocopherol>50mg/kg BHA=50mg/kg α-tocopherol>no-added antioxidant group. Also, TBARS values did not differ significantly (P>0.05) between 0 and 300 days in the 100mg/kg BHA and 100mg/kg α-tocopherol groups. In addition, the no-added antioxidant group had lower lightness and yellowness values than all the antioxidant groups. Sliced and vacuum-packaged kavurma with added antioxidant showed greater colour and lipid oxidative stability during storage than kavurma to which no antioxidant was added.     

A simple,sensitive HPLC-DAD method for simultaneous determination of carotenoids,chlorophylls and α-tocopherol in leafy vegetables

Leafy vegetables are the important components of our diet and are the source of several beneficial phytochemicals. A sensitive, simple analytical method is therefore required to precisely measure the phytochemical composition. A validated reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD) method was developed to determine simultaneously carotenoids, chlorophylls and α-tocopherol composition of six leafy vegetables (B. compestris, B. rapa, B. juncea, M. neglecta, and two spinach varieties). Carotenoids were extracted and efficiently separated using a tertiary mobile gradient system of methanol–water, water and MTBE in 40 min on a reversed phase C18 column. The method was simple, precise, accurate and highly reproducible. Twelve carotenoids namely lutein and its three isomers, β-carotene-5,6-epoxide, neoxanthin, violaxanthin, two cis-isomers of zeaxanthin, 8-apo-carotenal, all-trans-β-carotene and its 13-cis-isomer; one fatty acid ester (β-cryptoxanthin ester); α-tocopherol and chlorophyll a & b were quantified in vegetable leaves. α-Tocopherol, neoxanthin, violaxanthin, lutein, 8-apo-carotenal, chlorophyll a and all-trans-β-carotene were present in higher amounts. Significant variations in the major compounds were observed in the selected vegetables. It was concluded that the developed method was highly sensitive, accurate and can be used to analyze carotenoids, chlorophylls and α-tocopherol simultaneously in leafy vegetables as well as in other plant leaves.     

Degradation of carotenoids in pumpkin (Cucurbita maxima L.) slices as influenced by microwave vacuum drying

The aim of this study was to investigate the influence of microwave vacuum drying on carotenoids in pumpkin (Cucurbita maxima L.) slices. Carotenoids were measured using the reverse-phase high-performance liquid chromatography technique. It was shown that compared with hot air drying, microwave vacuum drying inhibited color changes and significantly (p < 0.05) improved total carotenoid retention (89.1%) in pumpkin slices. During the microwave vacuum drying process, microwave power had an important effect on total carotenoid and all-trans carotenoids. As microwave power increased, the total carotenoid content significantly decreased (p < 0.05), and the levels of individual carotenoids, including all-trans-α-carotene, all-trans-β-carotene, and all-trans-lutein, generally decreased. However, there was an overall upward trend for the levels of 13-cis-β-carotene, 15-cis-β-carotene, 9-cis-β-carotene, and 9-cis-α-carotene. The trans carotenoid quality of the finished products was improved within a certain range of vacuum levels. In addition to the degradation induced by microwave energy, isomerization was considered to be responsible for the loss of all-trans carotenoids. These results indicated that inappropriate drying methods and conditions might result in high losses of all-trans carotenoids in pumpkins.     

不同产地压榨山茶油活性成分比较分析

测定不同产地压榨山茶油中茶皂素、茶多酚、β-谷甾醇、α-生育酚含量,对结果进行统计分析。结果表明:除β-谷甾醇外,茶皂素、茶多酚和α-生育酚含量均存在产地间差异,其中茶皂素含量为海南和湖南>江西和广西(P均<0.05),但湖南与海南、江西与广西间无显著差异;茶多酚含量海南>湖南、江西和广西(P均<0.05),但湖南、江西与广西之间无显著差异;β-谷甾醇含量差异不显著(F=0.53,P>0.05);α-生育酚含量海南和湖南>广西(P均<0.05)。