坚果类食物清除ROO·的作用

采用一种测定样品清除氧自由基能力的方法,检测一些坚果类食物清除ROO·的作用,结果表明葵花子具有较强的清除ROO·的作用．花生、核桃等次之,栗子、莲子的作用最弱;另外,不同的坚果类食物清除ROO·的作用在水溶相与脂溶相分布也有所不同;相关分析表明坚果类食物脂溶相清除ROO·的能力与其脂肪含量有显著相关关系,水溶相清除ROO·的作用来源尚有待进一步研究     

坚果类食物清除R00的作用

采用一种测定样品清除氧币基能力的方法,检测一些坚果类食物清除ＲＯＯ的作用,结果表明蔡花子具有 的清除ＲＯＯ的作用,花生,核桃等次之,粟子,莲子的作用最弱,另外,不同的坚果类食物清除ＲＯＯ的作用在水溶相与脂溶相分布也有所不同。     

坚果果壳中活性物质体外抗氧化活性研究进展

作为坚果副产物的坚果果壳资源丰富,且富含多糖、多酚、黄酮等功能性成分,具有重要的开发价值。研究表明,坚果果壳提取物具有显著的抗氧化活性,可以清除体内自由基,减缓衰老,是开发天然抗氧化剂的优质资源。本文主要对坚果果壳中抗氧化活性物质体外抗氧化活性研究的重要性、各种研究方法的基本原理及应用情况进行了讨论,为坚果果壳抗氧化物质的开发利用提供参考。      

不同压榨方式澳洲坚果油品质及抗氧化活性比较

采用螺旋热榨、螺旋冷榨与液压压榨方式制备澳洲坚果油,运用气相色谱-质谱联用技术对其 脂肪酸组成进行分析,并以核桃油为对照,对其色差值、质量指标与总酚含量进行测定;同时,以核桃 油与芦丁标准品为对照,研究其对羟自由基、超氧阴离子自由基、2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸 （2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）自由基的清除能力及还原力。结果表明： 不同压榨方式澳洲坚果油中,液压压榨澳洲坚果油品质最佳,其评估色泽的L、a 、b值分别为99.78、 －1.44、2.99;质量指标酸价、过氧化值分别为0.648 6 mg/g、0.466 8 mmol/kg;含有5 种不饱和脂肪酸,总质量 分数为83.89%,其中油酸62.66%、棕榈油酸16.75%、亚油酸1.47%;总酚含量为679.11 μg/mL。不同压榨方式澳 洲坚果油的抗氧化活性与其质量浓度呈正相关,对羟自由基与超氧阴离子自由基有较强的清除作用,具有一定的 ABTS＋·清除能力与还原力。其中液压压榨澳洲坚果油对羟自由基的清除能力（半抑制浓度（half maximal inhibitory concentration,IC50）1.31 mg/mL）与还原力（IC50 14.78 mg/mL）优于热榨、冷榨澳洲坚果油,低于芦丁 标准品;对超氧阴离子自由基的清除能力（IC50 0.029 mg/mL）较强,相同质量浓度下优于冷榨澳洲坚果油与芦丁 标准品,低于热榨澳洲坚果油与核桃油;对ABTS＋·的清除能力（IC50 12.88 mg/mL）高于热榨澳洲坚果油与核桃 油,低于冷榨澳洲坚果油与芦丁标准品。相关性分析得出不同压榨方式澳洲坚果油与核桃油中的总酚含量与其清除 羟自由基（R＝0.951 9,P＜0.01）、ABTS＋·（R＝0.910 7,P＜0.01）的能力及还原力（R＝0.939 4,P＜0.01）之 间具有较高的相关性。     

两种方法测定香辛料提取物抗氧化活性的比较

本实验分别采用TBARS(硫代巴比妥酸反应物)法和FRAP(还原能力)法研究七种香辛料95%乙醇提取物的抗氧化作用。结果表明,七种香辛料提取物均有较好的抗氧化和还原能力。TBARS法测定抗氧化能力大小依次为:甘草>迷迭香>肉豆蔻>姜黄>丁香>白豆蔻>桂皮;FRAP法测定还原能力大小为:丁香>桂皮>肉豆蔻>迷迭香>姜黄>甘草>白豆蔻。两种方法得到的活性顺序存在很大差异,表明活性大小与其体系密切相关。     

提取方法对澳洲坚果油的化学成分及其抗氧化活性影响研究

本文旨在研究不同提取方法(水剂法、压榨法、溶剂法)对澳洲坚果油主要理化性质、活性成分、脂肪酸组成和红外光谱的影响,并采用DPPH自由基清除能力和氧化稳定性来综合评价澳洲坚果油的抗氧化活性。结果表明:三种提取方法得到的澳洲坚果油的理化性质(过氧化值、酸价、皂化值、碘值等)均符合国家食用油标准;与溶剂法和水剂法相比,压榨法得到的澳洲坚果油表现出较好的产品特性,其总酚酸含量((41.82±0.73)mg/100 g)、不饱和脂肪酸含量(83.67%)最高,且其氧化诱导时间((13.87±0.37)h)最长,清除DPPH自由基能力(46.70%)最强。红外谱图显示不同提取方法得到的澳洲坚果油均具有坚果油的特征吸收,且提取方法对其分子结构没有影响;通过分析不同提取方法得到的澳洲坚果油的品质,可为提取高品质澳洲坚果油奠定理论基础,同时也为澳洲坚果油的工业化生产提供了参考依据。      

澳洲坚果青皮多酚提取工艺优化及其抗氧化活性

以新鲜澳洲坚果青皮为原料,研究了澳洲坚果青皮多酚的提取工艺及抗氧化活性。在单因素实验的基础上,通过4因素3水平的正交实验优化澳洲坚果青皮多酚提取工艺,并以Trolox为对照,研究其对DPPH自由基和ABTS+自由基的清除能力以及总抗氧化能力。正交实验结果表明:提取时间为90 min、料液比为1∶50（g/m L）、提取温度为50℃、乙醇体积分数为40%为最佳提取工艺条件,在此条件下澳洲坚果青皮多酚提取量达到（1027.47±10.76）mg/100 g。抗氧化实验结果表明:澳洲坚果青皮多酚对DPPH自由基和ABTS+自由基的半数清除率IC50分别为4.13、112.94 mg/L,且其总抗氧化能力约为Trolox的1.7倍。由此可知,澳洲坚果青皮多酚具有很强的抗氧化能力,可用于制备天然抗氧化剂。      

用两种方法评价四种食品抗氧化剂的抗氧化活性

分别用DPPH·分光光度法及TBARS法研究了BHT、TBHQ、TP与VE的抗氧化活性。结果显示它们对DPPH·皆有清除作用,清除活性为TBHQ>TP>VE>BHT;对亚油酸的脂质过氧化也都有抑制作用,抑制活性为BHT>VE>TBHQ>TP。不同测试体系中它们表现出的抗氧化活性不同,值得注意。     

水剂法提取澳洲坚果油的化学成分及其抗氧化活性研究

采用水剂法从烘干的澳洲坚果仁中提取仁油,先对其基本理化性质进行分析,再通过红外、气相和液相色谱法对坚果油的红外特性、脂肪酸组成、生育酚、磷脂、甾醇进行分析,并通过测定其氧化诱导时间和清除DPPH自由基的能力来综合评价澳洲坚果油的抗氧化能力。结果表明:水剂法提取的澳洲坚果油的过氧化值、酸价、碘值、皂化值、折光率、水分及挥发物含量分别为0.59 mmoL/kg、0.28 mg KOH/g、74.21g/100g、198.78mg KOH/g、1.466 8、0.36%;红外谱图显示澳洲坚果油具有坚果油的特征吸收;脂肪酸分析发现其不饱和脂肪酸含量为83.45%,其中棕榈油酸和油酸含量分别为17.25%和61.44%;甾醇含量为55.51 mg/100g;总酚酸含量为31.87 mg/100g;磷脂和生育酚均未检出;澳洲坚果油的氧化诱导时间为11.44h,其清除DPPH自由基的能力达89.84%,具有良好的抗氧化能力。     

七种坚果仁中多酚、三萜含量及其抗氧化活性比较

坚果因富含抗氧化等活性成分已成为备受推崇的休闲食品。该研究将核桃、巴旦木、银杏果、花生、葵花籽、野生和种植香榧仁进行对比,评价7种坚果仁的活性成分含量及其抗氧化能力差异。结果表明,不同坚果的主要活性成分和抗氧化能力存在显著差异(P 0. 05)。葵花籽仁和核桃仁中分别具有最高的总黄酮(35. 16 mg Qu E/g DM)和总酚含量(9. 69 mg GAE/g DM)(槲皮素,quercetin equivalent,Qu E;干原料,dry material,DM;没食子酸,gallic acid equivalent,GAE),(齐墩果酸,oleanolic acid equivalent,OAE),其次为种植香榧仁;种植香榧仁具有最高的总三萜含量(4. 37 mg OAE/g DM),其次为核桃仁。抗氧化实验表明,种植香榧仁提取物具有最高的DPPH·和ABTS+·清除能力,其IC50值分别为0. 08 mg E./m L和0. 07 mg E./m L(提取物,extract. E.),但核桃仁提取物的Fe3+还原能力最高,其槲皮素当量还原能力为115. 25 mg Qu E/g E.,种植香榧仁的还原能力次之。以上结果表明,种植香榧仁具有较高的活性成分含量和抗氧化活性,是优于巴旦木、银杏果、花生和葵花籽仁的天然抗氧化剂资源。     

Antioxidant and antiproliferative activities of common edible nut seeds

Frequent consumption of nuts has been linked to a lowered risk of cardiovascular disease. Phytochemicals, especially phenolics, in nuts may be considered to be the major bioactive compounds for health benefits. Nine types of tree nuts and peanuts commonly available in the United States were evaluated for total phenolic and flavonoid contents, antioxidant, and antiproliferative activities. The profiles of total phenolics and flavonoids, including both soluble free and bound forms, were investigated by utilizing solvent extraction, base digestion, and solid-phase extraction methods. Walnuts had the highest total phenolic and flavonoid contents (1580.5 ± 58.0 mg/100 g, 744.8 ± 93.3 mg/100 g, respectively). Walnuts also possessed the highest total antioxidant activity (458.1 ± 14.0 μmol of vitamin C equiv/g of nut). Both soluble phenolic and flavonoid contents were positively correlated with total antioxidant activity (R² = 0.9901, p < 0.05; and R² = 0.9749, p < 0.05, respectively). The proliferation of HepG₂ and Caco-2 cells was significantly inhibited in a dose-dependent pattern after exposure to the extracts of nuts, with walnuts and pecans exhibiting the highest antiproliferative activity. These results provide new knowledge about health functions of nuts and may influence consumers toward purchasing nuts exhibiting greater potential health benefits.     

Evaluating the in vitro bioaccessibility of phenolics and antioxidant activity during consumption of dried fruits with nuts

Dried fruits and nuts are considered as healthy snacks and they are often consumed together in the Turkish diet. In order to investigate the effect of codigestion of dried fruits (figs, apricots, raisins) together with nuts (almonds, walnuts, hazelnuts), total phenolics (TP) and total antioxidant capacity (TAC) have been evaluated spectrophotometrically at different phases of simulated gastrointestinal (GI) digestion, using an in vitro model. TP, ABTS and CUPRAC results revealed that for all fruit–nut mixtures, the amount recovered in the dialyzed fraction was lower than the recovery of fruits or nuts alone, indicating an antagonistic effect. On the other hand, DPPH results showed that for fig–walnut, fig–hazelnut and apricot–hazelnut mixtures the quantity recovered in the dialyzed fractions were 35–107% higher than the recovery of fruits or nuts alone, representing a synergistic effect. Similarly, FRAP results also demonstrated a synergistic effect in case of fig–walnut, apricot–walnut and apricot–hazelnut mixtures (10–74% higher recovery). Current study provides valuable insights into the changes taking place during in vitro GI digestion of dried fruits and nuts.     

Edible films and coatings to prevent the detrimental effect of oxygen on food quality: Possibilities and limitations

Oxygen has a deleterious effect on the quality of a wide variety of food products. The application of edible films and coatings to food products represents a new approach to solve this problem. Edible films and coatings can include antioxidant agents in their formulation and at the same time, they represent a barrier to oxygen, which results in a better preservation of quality. The water activity of the product, as well as the ambient relative humidity, determines the antioxidant effect of films and coatings. This paper reviews the latest studies dealing with the effectiveness and application of antioxidant films and coatings.     

Review of Methods to Determine Antioxidant Capacities

Antioxidant capacity is related with compounds capable of protecting a biological system against the potentially harmful effect of processes or reactions involving reactive oxygen and nitrogen species (ROS and RNS). These protective effects of antioxidants have received increasing attention within biological, medical, nutritional, and agrochemical fields and resulted in the requirement of simple, convenient, and reliable antioxidant capacity determination methods. Many methods which differ from each other in terms of reaction mechanisms, oxidant and target/probe species, reaction conditions, and expression of results have been developed and tested in the literature. In this review, the methods most widely used for the determination of antioxidant capacity are evaluated, presenting the general principals, recent applications, and their strengths and limitations. Analysis conditions, substrate, and antioxidant concentration should simulate real food or biological systems as much as possible when selecting the antioxidant capacity method. The total antioxidant capacity value should include methods applicable to both lipophilic and hydrophilic antioxidants, with regards the similarity and differences of both hydrogen atom transfer and electron transfer mechanism. The methods including various ROS/RNS also have to be designed to comprehensively evaluate the antioxidant capacity of a sample.     

分光光度法测定大豆总皂甙含量

为建立一种测大豆总皂甙含量的新方法,以齐墩果酸作为标准品,采用分光光度法,配合薄层分析结果测定了经大孔树脂吸附法、正丁醇再分配法和混合法精制纯化后的３种大豆总皂甙试样含量。本测定方法的平均回收率为１００．５８％,ＲＳＤ为３．３４％,方法简便,重现性好,可作为大豆皂甙含是检测的一种手段。     

Effect of ingestion of dark chocolates with similar lipid composition and different cocoa content on antioxidant and lipid status in healthy humans

The association between in vitro antioxidant capacity of dark chocolates with different cocoa percentage and the in vivo response on antioxidant status was investigated. In a randomized crossover design, 15 healthy volunteer consumed 100 g of high antioxidants dark chocolate (HADC) or dark chocolate (DC). In vitro, HADC displayed a higher Total Antioxidant Capacity (TAC) than DC. In vivo, plasma TAC significantly peaked 2 h after ingestion of both chocolates. TAC levels went back to zero 5 h after DC ingestion whilst levels remained significantly higher for HADC. HADC induced a significantly higher urinary TAC in the 5-12 h interval time than DC. No change was detected in urinary excretion of F2-isoprostanes. Plasma thiols and triacylglycerol (TG) levels significantly increased for both chocolate with a peak at 2 h remaining significantly higher for DC after 5 h respect to HADC. Results provide evidence of a direct association between antioxidant content of chocolate and the extent of in vivo response on plasma antioxidant capacity.     

10种蜂蜜中的抗氧化物质及其抗氧化能力分析

目的分析市售蜂蜜与农家蜂蜜中抗氧化物质含量的多少,为我国蜂蜜品质的评价和鉴别提供一定的基础。方法采用分光光度计法测定3种市售蜂蜜和7种农家蜂蜜中总酚、总黄酮、脯氨酸含量、DPPH自由基清除能力、超氧阴离子清除能力及总抗氧化能力,通过数据间的显著性分析和相关性分析明确各指标之间的关系。结果市售蜂蜜和农家蜂蜜总酚含量均值分别为24.93 mg/100 g和30.32 mg/100 g;市售3种蜂蜜中的总黄酮含量均低于20 mg/100 g,而农家的7种蜂蜜均高于20 mg/100 g;农家蜂蜜脯氨酸含量的均值是市售蜂蜜的2.5倍之多。市售蜂蜜的DPPH清除能力、超氧阴离子清除作用和总抗氧化能力均高于农家蜂蜜。蜂蜜的抗氧化能力与总酚、总黄酮和脯氨酸含量呈显著的正相关。结论 10种蜂蜜的各项指标间差异显著,农家蜂蜜的抗氧化物质含量高于市售蜂蜜,而市售蜂蜜的抗氧化能力高于农家蜂蜜,蜂蜜的抗氧化物质与抗氧化能力间呈显著的相关性。