茶多酚对玉米油抗氧化的研究

对茶多酚的抗氧化作用及其影响因素进行研究。采用BHA、BHT、VE以及水溶性茶多酚做阳性对照,通过各还原物对油脂的抗氧化能力比较得出茶多酚的抗氧化作用。在明确茶多酚具有很强的抗氧化作用基础上,研究了多种有机酸的添加和光照对其抗氧化能力的影响。结果表明:茶多酚的抗氧化能力远大于已知人工合成抗氧化剂BHA、BHT、VE,使用茶多酚的同时加入有机酸能有效提高茶多酚的抗氧化能力,茶多酚在避光和低温的条件下抗氧化效果较好。     

茶多酚抗氧化作用的研究与应用

开发利用天然抗氧化剂是当前食品科技发展的趋势。茶叶中富含的茶多酚是一种理想的天然抗氧化剂,对油脂的抗氧化能力比BHA、VE强。本文叙述了油脂氧化及抗氧化的原理。介绍了茶多酚的组成、结构、对油脂的抗氧化作用。探讨了茶多酚抗氧化作用的机理。简要叙述了从茶叶中提取茶多酚的方法及茶多酚作为食品添加剂在食品业中的应用前景。     

茶多酚不同分散体系对葵花籽油抗氧化作用的研究

茶多酚对植物油脂具有很好的抗氧化作用,但由于它的脂溶性差而不能直接使用于油脂中。本文就茶多酚的乳化法和溶剂法两种分散体系对葵花籽油的抗氧化性进行了研究。试验结果表明:茶多酚溶剂法分散体系具有更好的抗氧化性,其最佳使用浓度为0.015％。同时,维生素E对茶多酚的抗氧化具有增效作用,对于茶多酚溶剂法分散体系,其最佳使用浓度为0.04％。     

茶多酚的药理研究

目的综述茶多酚的药理作用及作用机制。方法对国内外有代表性的文献加以归纳总结。结果与结论茶多酚具有降血压、降血脂、预防心血管病、预防癌症、抑制病源微生物、抗辐射损伤和防衰延寿等作用,其机制主要是茶多酚的抗氧化作用。     

脂溶性茶多酚对共轭亚油酸的抗氧化性研究

鉴于商品茶多酚的脂溶性较差,将茶多酚合成脂溶性茶多酚以及在茶多酚中添加乳化剂的方法增强其在共轭亚油酸(CLA)中的溶解性,同时试验它们对CLA的抗氧化作用。结果表明,脂溶性茶多酚在CLA中的溶解度明显增加,对CLA的抗氧化作用好于BHT,它能抑制CLA中TBA反应物的形成,但对于CLA过氧化值的影响不如茶多酚大。添加乳化剂(span40,span60)及柠檬酸能增强茶多酚在CLA中的抗氧化效果。     

乳化剂对茶多酚和脂溶性茶多酚抗亚油酸及其乳化体系氧化作用的影响注

本文研究了茶多酚和脂溶性茶多酚对亚油酸及其乳化体系抗氧化作用的影响，结果发现茶多酚和脂溶性茶多酚联合且在亚油酸及其乳化体系中的抗氧化作用都显著优于茶多酚和脂溶性茶多酚单独处理组。进一步研究茶多酚和脂溶性茶多酚在油／水界面分配系数的实验证明，乳化剂能显著增加水溶性抗溶性茶多酚联合处理组抗氧化的协同增效作用提供了理论基础。     

茶多酚及其改性衍生物抗氧化性研究

茶多酚作为一种天然的抗氧化食品添加剂,具有很多生理功能,如抗氧化、预防心血管疾病、抗肿瘤、抗辐射、抗菌抗病毒、抗炎症等,其中抗氧化是其主要功能之一,并且通过改性还能够进一步提高其抗氧化性,因此本文对茶多酚及改性衍生物的抗氧化性评价及应用等进行了综述,研究者的体外研究表明,茶多酚能够有效抑制脂质过氧化,并且效果优于维生素C和维生素E,显示了茶多酚在抗氧化方面的优良性能.并且其抗氧化作用在体内也得到了证实.将茶多酚运用到肉制品和油脂上也证实具有优良的抗氧化性能,比人工合成抗氧化剂BHT、BHA还好,并且茶多酚的安全性高于人工合成抗氧化剂.而茶多酚的改性衍生物具有更强的抗氧化性,但在其衍生物的生产上还存在一些问题,主要表现为活性有部分丧失,需要进一步研究来解决,此问题的解决也将带来巨大的经济效益和实用价值.     

不同纯度茶多酚和茶黄素的抗氧化活性（英文）

采用1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除实验和氧化损伤酵母细胞实验模型,对不同纯度的茶多酚和茶黄素的抗氧化活性进行比较研究。结果表明,茶多酚和茶黄素均对DPPH自由基具有一定的清除能力。氧化损伤酵母细胞实验结果表明,茶多酚和茶黄素对酵母细胞氧化损伤具有一定的保护作用,且在一定浓度范围内其保护能力呈剂量依赖关系。98%茶多酚对DPPH自由基清除率最高;60%茶黄素和90%茶多酚对H2O2氧化损伤酵母细胞保护作用相当;60%茶黄素对紫外氧化损伤酵母细胞保护作用最强。茶多酚和茶黄素具有一定的体外和细胞抗氧化活性,且不同方法测得的抗氧化活性存在一定的差异。     

不同纯度茶多酚和茶黄素的抗氧化活性

采用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除实验和氧化损伤酵母细胞实验模型,对不同纯度的茶多酚和茶黄素的抗氧化活性进行比较研究。结果表明,茶多酚和茶黄素均对DPPH自由基具有一定的清除能力。氧化损伤酵母细胞实验结果表明,茶多酚和茶黄素对酵母细胞氧化损伤具有一定的保护作用,且在一定浓度范围内其保护能力呈剂量依赖关系。98%茶多酚对DPPH自由基清除率最高;60%茶黄素和90%茶多酚对H2O2氧化损伤酵母细胞保护作用相当;60%茶黄素对紫外氧化损伤酵母细胞保护作用最强。茶多酚和茶黄素具有一定的体外和细胞抗氧化活性,且不同方法测得的抗氧化活性存在一定的差异。     

茶多酚将是21世纪对人类健康产生巨大效果的化合物

饮茶有利于健康与其特定的化学成分分不开．其主要成分就是茶多酚。茶多酚是茶叶中的一种多酚类化合物,具有优异的抗氧化活性。《辞海》中对茶多酚的表述是：“一种存在干茶叶中的杂环多元酚类。通常由绿茶（干叶含量25％）经水萃取分离及纯化制得。具有降血糖、血压、抑制动脉硬化、杀菌、消炎及抗氧化作用．广泛用作食品保鲜剂和天然营养品。”     

茶多酚与Vc对猪油乳化体系协同抗氧化性研究

茶多酚与 Vc在猪油乳化体系中的协同抗氧化性 ,初步探讨了协同效应的条件和内在机理。结果表明 ,在猪油乳化体系中 ,TP与 Vc具有显著的协同抗氧化作用。高浓度的 Vc在低浓度 TP和高浓度 TP组合中 ,表现出较强的抗氧化协同效应 ,适当的 TP浓度与 Vc组合时 ,表现出稳定而较强的协同抗氧化效能。当 TP浓度上升到一定水平后 ,协同抗氧化性消失 ,TP达到抗氧化一助氧化作用的平衡浓度 ;此平衡浓度主要受 Vc浓度的影响。     

Effects of water-soluble natural antioxidants on photosensitized oxidation of conjugated linoleic acid in an oil-in-water emulsion system

ABSTRACT:  The effect of photosensitized oxidation of conjugated linoleic acid in an oil-in-water (o/w) emulsion system was studied. Water-soluble natural antioxidants, including apple polyphenols from apple extract, green tea extract, 4-hydroxy-2(or 5)-ethyl-5(or2)-methyl-3(2H)-furanone(HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), and ascorbic acid, were tested for antioxidant activity in this system. The green tea extract showed the highest antioxidant activity followed by ascorbic acid. Apple polyphenols did not give significant antioxidant activity. HEMF and HDMF exhibited a prooxidant effect. The antioxidant activity of tea catechins was also investigated. Of them, EGCG and ECG exhibited antioxidant activity at 50 ppm, but the antioxidant activity between them was not significantly different ( P < 0.05). Comparatively, EC, EGC, and GCG showed no significant antioxidative effect at 50 ppm. When the concentration increased to 100 ppm, the antioxidant activity of ECG and EGCG significantly increased compared with that at 50 ppm, and EGCG had higher antioxidant activity than ECG. GCG also showed significant antioxidant activity at 100 ppm. EGCG exhibited the highest antioxidant activity among the tea catechins in the emulsion system at 100 ppm.     

Evaluation of antioxidative activity of vegetable extracts in linoleic acid emulsion and phospholipid bilayers

The antioxidative effects of vegetable extracts were evaluated using linoleic acid emulsion and liposomal phospholipid suspension systems. First, the antioxidative activities of water, ethanol and 2% metaphosphoric acid extracts of the vegetables were investigated by measuring the rate of oxygen consumption in the peroxidation of linoleic acid initiated by a radical generator, 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), with a Clark electrode in the absence of metal chelators. Ethanol extracts of moroheiya and perilla exhibited the highest antioxidative activities. Without metal chelators, 12 ethanol extracts and one water extract acted as prooxidants, and this phenomenon could be attributed to the prooxidant action of ascorbic acid in the presence of free transition metal ions. Next, peroxyl radical-scavenging activities of vegetable extracts were examined by adding a metal chelator, diethylenetriaminepentaacetic acid (DTPA), to the linoleic acid emulsion system. The results were compared with their antioxidative activities in phospholipid bilayers by measuring the inhibition of lipid peroxidation in large unilamellar vesicles composed of egg yolk phosphatidylcholine (PC). A good correlation was observed between the antioxidative activities obtained from these two systems. The antioxidative activities in the liposomal phospholipid suspension system correlated with total contents of ascorbic acid and polyphenols in vegetable extracts. © 1999 Society of Chemical Industry     

Antioxidative capacity of tomato products

The antioxidative capacity of methanol/water and hexane extracts of five tomato juices, four canned tomatoes and four tomato pastes was measured using two test systems: with 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS⁺) and with linoleic acid emulsion. In both the ABTS assay and the linoleic acid system, most of the antioxidative capacity of analysed products was from the methanol-water fraction, which contained polyphenols and ascorbic acid. On the basis of the wet weight of the tomato products, tomato pastes had the highest activity towards ABTS⁺ (micromoles of Trolox equivalents per gram) followed by tomato juices, and canned tomatoes. The inhibition of formation of thiobarbituric acid-reactive substances in the linoleic acid emulsion was strongly dependent on antioxidant concentration. The results suggest that tomato products, in addition to fresh tomatoes, may also be important in supplying dietary antioxidant, especially polyphenols and carotenoids.     

Antioxidant Activity of Fungus Suihs bovinus (L: Fr.) O. Kuntze

Two major antioxidative compounds were isolated from wild mushrooms, Suillus bovinus (L: Fr.) O. Kuntze, and studied for antioxidative activity by comparison with other antioxidants, BHA and tocopherol. One compound was an orange pigment identified as variegatic acid (3,3′,4,4′-tetrahydroxy puluvinic acid) and the other was an orange-red pigment, possibly diboviquinone-4,4. The variegatic acid had strong antioxidative activity in an emulsion system as shown by peroxide value (POV) of linoleic acid and in an oil system as shown by the POV of methyl linoleate and weight gain of soybean oil. The second compound was active only in the emulsion system.     

茶多酚和植酸用于佛山得心斋扎蹄常温保鲜

佛山得心斋扎蹄是佛山传统特色卤肉食品,其透明软包装常温保鲜寿命很短。在前期研究结果的基础上,采用天然产物茶多酚和植酸作为添加剂处理扎蹄,有效地延长了扎蹄在常温下的保鲜寿命。研究结果表明,茶多酚对扎蹄油脂有明显的抗氧化作用,植酸对茶多酚的抗氧化作用有明显的增效作用。茶多酚和植酸的作用与其浓度有关。采用0.05%茶多酚+0.03%植酸,在扎蹄酝煮结束前1h加入卤煮液中,以NY/PVDC/PC复合塑料薄膜袋抽真空包装,再经常压下蒸煮灭菌处理过的扎蹄,在35℃和24h光照下,保鲜寿命可达70天以上。     

啤酒多酚的抗氧化性研究

通过TRAP值分析啤酒多酚抗氧化性，实验发现啤酒中( )-儿茶素和阿魏酸对抗氧化性贡献较大，花色苷类物质也有一定的贡献。并且酚类抗氧化能力一般都高于外加抗氧化剂，监测酿造过程氧化变化情况发现，TRAP值基本随多酚含量的变化而变。     

茶多酚与VC对猪油乳化体系协同抗氧化性研究

研究了茶多酚与ＶＣ在猪油乳化体系中的协同抗氧化性,初步探讨了协同效应的条件和内在机理。结果表明在猪油乳化体系中,ＴＰ与ＶＣ具有显著的协同抗氧化作用。高浓度的ＶＣ在低浓度ＴＰ,表现出较强的抗氧化协同效应,适当的ＴＰ浓度与ＶＣ组合时,表现出稳定而较强的协同抗氧化效能。当ＴＰ浓度上升到一定水平后,协同抗氧化性消失,ＴＰ达到抗氧化－助氧化作用的平衡浓度;此平衡浓度主要受ＶＣ浓度的影响。     

Major Mango Polyphenols and Their Potential Significance to Human Health

ABSTRACT: The mango is a rich source of various polyphenolic compounds. The major polyphenols in the mango in terms of antioxidative capacity and/or quantity are: mangiferin, catechins, quercetin, kaempferol, rhamnetin, anthocyanins, gallic and ellagic acids, propyl and methyl gallate, benzoic acid, and protocatechuic acid. The nutraceutical and pharmaceutical significance of mangiferin, which is a special polyphenol in the mango has been extensively demonstrated and continues to attract much attention especially in its potential to combat degenerative diseases like heart diseases and cancer. The amounts of the different polyphenolic compounds in the mango vary from part to part (pulp, peel, seed, bark, leaf, and flower) with most polyphenols being found in all the parts. Mango polyphenols, like other polyphenolic compounds, work mainly as antioxidants, a property that enables them to protect human cells against damage due to oxidative stress leading to lipid peroxidation, DNA damage, and many degenerative diseases. Use of pure isolated compounds has been found to be less effective than the use of crude mixtures from the particular mango part suggesting that synergism of the various mango polyphenols is important for maximum antioxidative activity. In this article, we review the major mango polyphenols, looking at their proposed antioxidative activity, estimated amounts in the different parts, their structures, suggested modes of action, and related significance to human health, with great emphasis on mangiferin.