牛乳不同成分对枣多酚体外抗氧化活性的影响

多酚是一类天然存在的抗氧化物质,大量研究表明摄入多酚可降低许多疾病的发生风险。然而富含多酚的食物常与牛乳一同食用,已有研究表明牛乳会抑制多酚的体内吸收,但牛乳中各成分在这一影响中所起的作用及相关机制尚不明确,因此本研究以市场占有率很高的"枣汁奶"为研究模型,主要评价了牛乳不同成分对枣多酚抗氧化活性的影响。结果表明:添加全脂乳或脱脂乳均显著抑制枣多酚的抗氧化活性,而牛乳超滤液(主要成分为牛乳中的碳水化合物和小分子物质)则无影响。经胃肠消化酶消化后,脱脂乳抑制抗氧化活性的作用减弱,而全脂乳仍保持较强的抑制作用,表明在消化过程中脂肪的存在会影响枣多酚的抗氧化活性。     

体外模拟消化对蓝莓皮渣粗提物抗氧化成分及其活性的影响

采用体外模拟消化的方法对蓝莓皮渣粗提物进行试验,测定在模拟消化过程中抗氧化成分及其活性的变化规律,为今后开发利用蓝莓皮渣资源提供参考依据。以蓝莓加工的副产物-果皮渣为原料,采用体外模拟消化法,分析经模拟胃肠消化后其花色苷、多酚、黄酮含量及其抗氧化活性的变化情况。结果表明,模拟胃消化后,粗提物组的花色苷、多酚、黄酮及抗氧化活性显著提高(p0.05),在胃消化30 min活性成分释放量达到最大值,而对照组的多酚和花色苷含量与消化前变化无显著差异(p0.05),但胃酸对黄酮释放有一定促进作用。经模拟肠消化后,粗提物组的抗氧化活性物质及总抗氧化活性在消化2.0 h~3.0 h后均达最大值,但抗氧化作用略低于模拟胃消化的活性,可能由于多酚和花色苷的含量降低。本试验结果可为进一步提高蓝莓皮渣的深加工附加值,开发该类功能性食品提供试验依据。     

酱油渣所含抗氧化成分的价值

通过对各种大豆发酵食品的抗氧化性进行研究，发现豆酱中具有很强抗氧化能力的成分是o-二羟基异黄酮（ODD，其产生在接种和制曲过程中。人体内产生的活性氧自由基和自动氧化物质引起疾病、致癌和老化现象。利用食物中的抗氧化物质抑制氧化引起的不良反应，例如在食物中添加抗氧化物质，采用生物工程提高食物中抗氧化成分的含量等，有助于预防疾病。近年来发现酱油渣中含有的成分具有较强的生理活性，研究人员试图将其提取出来用于保健食品、化妆品以及医药等。     

油炸方式对紫甘蓝在消化过程中抗氧化成分及活性的影响

以紫甘蓝为研究对象,通过体外模拟胃肠消化模型,探究不同油炸方式后,紫甘蓝总酚和花色苷的释放规律,用ABTS、ORAC两种评价抗氧化能力的方法分析油炸紫甘蓝在胃肠消化过程中抗氧化能力的变化。结果表明,胃肠液消化可以促进真空油炸紫甘蓝中的抗氧化物质的释放和抗氧化性的增加。在同一个热驱动力的条件下,真空油炸紫甘蓝的抗氧化成分含量和抗氧化性均高于常压油炸紫甘蓝;且随着油炸温度的升高,真空油炸紫甘蓝所释放的抗氧化成分含量和抗氧化性都呈现升高的趋势。该研究通过模拟体外胃肠消化过程,更客观地评价2种油炸方式对紫甘蓝的活性物质和抗氧化能力影响,为更真实、合理地评价加工紫甘蓝的抗氧化功能提供参考。     

体外仿生消化对金银花醇提物成分及抗氧化活性的影响

为探究金银花醇提物在体外仿生消化中成分含量及抗氧化活性变化规律,通过测定模拟胃肠消化前后金银花醇提物中12种成分含量、总体抗氧化能力、羟自由基(·OH)清除率和DPPH自由基清除率,并进行成分含量和抗氧化活性变化相关性分析。结果显示,酚酸类成分含量随模拟胃消化时间延长而降低,而在模拟肠消化过程中无显著性变化(P>0.05)。黄酮类成分含量整体呈先上升后下降趋势,而在模拟肠消化过程中无显著性变化(P>0.05)。仿生消化过程中环烯醚萜类成分含量无显著性变化(P>0.05)。经模拟胃肠消化后,消化产物总体抗氧化能力及对·OH和DPPH自由基清除率均显著降低(P<0.05),并与酚酸和黄酮含量呈显著正相关(P<0.05)。胃肠道环境均能促进金银花中酚酸和黄酮类成分降解,并显著降低其抗氧化活性,为进一步研究金银花体内胃肠消化提供一定的理论参考。     

膜分离对福建产不同茶类提取物化学组成和抗氧化活性的影响

为探究不同茶类水提液在多级膜分离过程中主要生化成分和体外抗氧化活性的变化情况,采用不同孔径的超滤膜（截留分子质量分别为20、10、3.5 kDa）对福建主要茶类（绿茶、白茶、闽南乌龙、闽北乌龙、红茶）的水提液进行分离,制得不同分子质量区间的茶叶提取物,经喷雾干燥后,考察每一区间茶粉的生化成分及体外抗氧化活性。首先对各茶粉进行紫外全波谱扫描,其次检测其主要生化成分组成,最后评价其体外抗氧化能力。结果表明,各茶粉样品的紫外吸收光谱变化情况较为相似,均在210 nm和274 nm波长处有2个较为明显的吸收峰;274 nm波长处的吸光度与茶粉中的游离氨基酸、咖啡碱、没食子酸、表儿茶素没食子酸酯含量均呈极显著正相关,与表没食子儿茶素含量呈极显著负相关,与表儿茶素含量呈显著负相关。膜分离会影响各茶粉生化成分的分布情况及体外抗氧化能力变化,其中20 kDa超滤膜对各成分的分布情况影响最大,抗氧化活性变化幅度也最大,红茶20 kDa超滤膜截留液部分抗氧化活性最高,其余茶类20 kDa超滤膜透过液部分抗氧化活性最高。不同茶类的生化成分及体外抗氧化活力差异较大,不同茶类在膜分离过程中各生化成分及体外抗氧化...     

天然食品中抗氧化物质的开发

对引起食品氧化的自由基、活性氧及危害;天然食物中存在的一些抗氧化成分及复合成分;抗氧化成分的评价方法进行了论述。对开发采用天然抗氧化成分的绿色食品有一定意义。     

细胞抗氧化活性方法在食物抗氧化活性评价中的研究进展

由体内过剩自由基引起的心脑血管疾病和癌症病人日渐增加,通过抗氧化物质的作用清除体内过量的自由基是减少此类疾病发生的最主要而有效的方法。大量研究证实,植物化学物质具有显著的抗氧化作用,这些物质的最好来源是水果、蔬菜和谷物等,其在体内的抗氧化效果及活性评价是当前功能食品研究的热点。细胞抗氧化活性(CAA)测定方法是目前建立起的能有效预测植物化学物质在生物系统中抗氧化活性的评价方法,被广泛用于食物中抗氧化活性物质的功能评价。本文综述国内外关于CAA测定方法及其在抗氧化功能食品评价中的研究进展。     

体外模拟消化过程中核桃花提取物抗氧化活性的变化

为研究体外模拟消化过程中核桃花提取物抗氧化活性的变化,对核桃花提取物依次进行模拟口腔消化、胃消化和小肠消化,分别采用福林酚法和亚硝酸钠-硝酸铝法测定核桃花提取物在不同消化阶段的总酚和总黄酮含量,以DPPH自由基、ABTS自由基清除能力和铁还原能力为指标,考察核桃花提取物抗氧化活性的变化情况。结果表明：在口腔消化、胃消化和小肠消化过程中,核桃花提取物的总酚、总黄酮含量以及抗氧化活性均呈下降趋势。其中总酚含量从消化前的3.30 mg/mL降至消化后的0.62 mg/mL,降低了81.21%;总黄酮含量从2.88 mg/mL降至0.02 mg/mL,降低了99.31%;核桃花提取物清除DPPH自由基的IC50值从211.02 μg/mL上升到424.45 μg/mL,清除ABTS自由基的IC50值从220.63 μg/mL上升至421.82 μg/mL,铁还原能力从106.13 μg/mL下降为40.47 μg/mL。在模拟胃消化和小肠消化阶段,酸碱环境和消化酶的作用破坏了核桃花提取物中的抗氧化成分,使其抗氧化活性发生了显著下降。     

高活性抗氧化肽的体外胃肠耐受性研究

研究了高活性抗氧化肽在体外模拟胃肠消化吸收过程中的耐受性。以6条抗氧化合成肽为研究对象,采用体外胃肠消化模型和Caco-2细胞单层模型,模拟其胃肠消化吸收过程,分别测定抗氧化肽在胃肠消化中的降解与转化、含量变化及以TEAC活性和ORAC活性为指标的抗氧化活性变化。结果表明,6条抗氧化肽均耐受胃消化,不耐受肠的消化,但是经胃肠消化吸收后仍具有很强的抗氧化活性,分别高于阳性对照还原型GSH和Vc;YPWY、GWEW和YEW在肠阶段发生C端氨基酸降解,生成短肽YPW、GWE和YE,而且可以完整地透过Caco-2细胞。这项研究为这些抗氧化肽作为功能配料进行开发利用提供了理论依据。     

Antioxidants Bound to an Insoluble Food Matrix: Their Analysis,Regeneration Behavior,and Physiological Importance

Dietary antioxidants play an important role in human health by counteracting oxidative stress and preventing chronic diseases. Most common dietary antioxidants in foods are vitamins, carotenoids, phenolic compounds, sulfur‐containing compounds, and neoformed antioxidants. Antioxidants may be present in free soluble or bound insoluble forms in foods. Antioxidants bound to insoluble food matrices have gained the spotlight because they exert their antioxidant effects much longer than free soluble ones. A direct procedure called QUENCHER has been shown to accurately measure the antioxidant capacity of antioxidants bound to insoluble matrices. This procedure overcomes the drawbacks of extraction‐dependent classical assays leading to underestimation of the total antioxidant capacity (TAC) of foods. This review focuses on antioxidants that are found naturally in foods or are formed in foods during processing specifically the antioxidants bound to the insoluble food matrices. The literature gap on the importance of bound antioxidants, their physiological relevance, and methods for measurement of their antioxidant capacity will be filled by this comprehensive review. In particular, chemical properties and health effects of food antioxidants, measurement of the TAC of foods by the QUENCHER method, digestion behavior of bound insoluble antioxidants, and their interactions with free soluble antioxidants are discussed throughout this review.     

In vitro procedure to predict apparent antioxidant release from wholegrain foods measured using three different analytical methods

Several methods have been applied to the measurement of antioxidants in biological samples. Extraction methods have previously relied on chemical methods which are non‐physiological. This paper reports the use of an in vitro method with enzymatic and fermentation steps, designed to mimic digestion through the gastrointestinal tract, on release of antioxidants from a range of wholegrain foods. A total of 41 samples, (31 raw foods, 10 of which were also analysed after cooking) were analysed using the ferric reducing antioxidant capacity and Trolox equivalent antioxidant capacity methods. Six samples were also measured using the oxygen radical absorption capacity method. The three antioxidant assay methods gave different apparent antioxidant activity trends, and the range of values was dependent on the type of food. The effects of cooking were mainly observed in the early stages of the incubation procedure, suggesting that cooking may destroy soluble antioxidants but not those bound within the food matrix. For all samples, apparent antioxidant release increased during the incubation period, suggesting that antioxidants bound within the food matrix may be released and exert their effects in different regions of the gastrointestinal tract. Copyright © 2005 Society of Chemical Industry     

软枣猕猴桃在体外模拟消化过程中酚类物质及抗氧化活性的变化规律

本研究以4 种软枣猕猴桃为原料，探讨了其整果、游离型酚类提取物和果渣样品在体外模拟消化过程中酚类物质的含量及抗氧化活性的变化规律，采用福林-酚法测定样品每个消化阶段总酚含量，采用超高效液相色谱-四极杆飞行时间质谱联用和高效液相色谱-光电二极管阵列质谱联用对软枣猕猴桃中酚类单体化合物进行定性定量分析。通过过氧自由基清除能力来探究胃肠消化处理对软枣猕猴桃抗氧化活性的影响，并通过细胞抗氧化活性进一步探究体外模拟消化后样品的抗氧化水平。结果表明：在体外模拟消化过程中，软枣猕猴桃整果和游离型酚类提取物中总酚含量的变化趋势相同：未消化＞口腔＞胃＞肠；果渣中总酚含量表现出不同的变化趋势：肠＞胃＞未消化＞口腔。不同的消化阶段环境条件不同，胃（低pH值环境）和肠（高pH值环境）对酚类化合物稳定性影响不同，使酚类物质发生降解或转化；同时，酚类化合物结构也影响其自身的降解和转化。由于酚类是软枣猕猴桃中最主要的抗氧化活性物质，在体外消化过程中，过氧自由基清除能力与其对应的酚类含量变化趋势一致。本研究结果为软枣猕猴桃天然产品的开发及应用提供科学依据。     

Effect of malting on antioxidant capacity and vitamin E content in different barley genotypes

Unprocessed barley is known to contain relatively high levels of antioxidants, which play a critical role in human health and the preservation of food and drink products. However, there are limited data on how the antioxidant levels in barley are affected by malting, and whether the level of antioxidants in the processed malt differs between barley varieties. This study aimed to determine the levels of individual vitamin E isomers, total vitamin E content and total antioxidant capacity before, during and after malting in 12 covered and two hulless barley genotypes. Vitamin E content and antioxidant capacity were determined by high‐performance liquid chromatography (HPLC) and ability to scavenge DPPH radicals, respectively. The vitamin E content of most genotypes was reduced after steeping, germination and kilning compared with the unprocessed samples. However, the antioxidant capacity in the malt was higher than in the unprocessed samples for the majority of the genotypes. While there was variation in the percentage change in antioxidant capacity between varieties, the antioxidant capacity of samples after malting was directly correlated with their antioxidant capacity before processing (r = 0.9, n = 14, p < 0.05). These results indicate that barley varieties that have higher antioxidant capacity at harvest retain their antioxidants after malting. Thus, these varieties are likely to be the most suitable for producing malts with the added health benefits and anti‐spoiling properties associated with greater antioxidant content. Copyright © 2015 The Institute of Brewing & Distilling     

体外模拟胃肠消化过程中猕猴桃抗氧化成分及活性的变化

研究猕猴桃果浆和果汁在体外模拟胃肠消化过程中多酚黄酮类物质含量及抗氧化活性的变化规律。采用铁还原力,以及DPPH自由基、超氧阴离子自由基、羟自由基清除法测定抗氧化性。结果显示,消化后多酚和黄酮物质释放量增加。果浆消化后最大释放量分别为消化前的1.62倍和2.40倍;果汁消化后多酚、黄酮的最大释放量分别是消化前的1.63倍和2.90倍。果汁、果浆的DPPH自由基、超氧阴离子自由基和羟自由基清除率以及铁还原力均在模拟胃消化1 h和肠消化1 h后达到最大值,随后开始下降并趋于稳定。果浆和果汁的抗氧化能力虽不同,但变化规律类似。研究表明,模拟胃肠消化能促进猕猴桃多酚、黄酮的释放,提高抗氧化活性。     

Changes in sour cherry (Prunus cerasus L.) antioxidants during nectar processing and in vitro gastrointestinal digestion

Sour cherry (Prunus cerasus L.) is rich in polyphenols, and like its processed products, is especially rich in anthocyanins. We have applied HPLC, spectrophotometric and on-line antioxidant detection methods to follow the fate of cherry antioxidants during an entire multi-step industrial-scale processing strategy. This was performed for 22 sampling points, with five independent repeats from a commercial cherry nectar production process. Anthocyanins contributed to >50% of the total antioxidant capacity of the samples. An in vitro gastrointestinal (GI) digestion system was used to investigate serum availability of antioxidants. In this system anthocyanin bioavailability was much higher in the processed nectar than in the fresh fruit. Together these results indicate that processed sour cherry nectar is a rich source of stable antioxidants with high bioavailability, auguring well for the potential health-promoting capacity of sour cherry products.     

天然抗氧化剂抑制油脂氧化的研究进展

油脂在长期贮藏中易受多种因素影响发生氧化酸败,不仅影响食物感官,降低营养价值,同时产生一些有毒物质导致人体衰老、癌症以及多种慢性疾病的发生。天然抗氧化剂因具有安全性高、抗氧化能力较强的特点,已被普遍运用于油脂抗氧化中。从酚类、色素类、多肽类、甾醇类物质以及多糖类物质5个方面,综述了近年来从动植物中提取的天然抗氧化物质对油脂抗氧化的作用,旨在为天然抗氧化剂的开发、应用,油脂储存、保质研究提供参考。     

Food antioxidant capacity determined by chemical methods may underestimate the physiological antioxidant capacity

Antioxidant capacity assays are of growing interest in the study of dietary antioxidant properties since they are able to analyse a complex mixture of antioxidants and its synergistic interactions. However, most of the antioxidant capacity assays in the literature are limited by the antioxidant extraction technique, since some antioxidants may remain associated in the extraction residues. The objective of this work was to compare an in vitro physiological procedure for antioxidant extraction with a methanol/acetone/water extraction (chemical procedure). Enzymatic digestions and in vitro colonic fermentations were used on solid plant foods daily consumed in the Spanish diet to estimate the total antioxidant capacity released during the entire digestion process. The in vitro physiological procedure yielded a higher antioxidant capacity than the chemical procedure (7000 and 900 μmol trolox equivalents measured by ABTS, respectively). Our results suggest that determination of antioxidant capacity in food chemical extracts may underestimate the real antioxidant capacity that may be in close contact with the intestinal lumen.     

桉叶多酚提取物体内外抗氧化活性评价

桉叶资源丰富且生物活性高,但少有研究对桉叶多酚提取物进行系统的抗氧化活性评价。本实验旨在研究纯化后桉叶多酚提取物体内外抗氧化活性。以化学法、RAW264.7巨噬细胞模型、秀丽隐杆线虫（以下简称线虫）模型为评价方法,以自由基清除率、抗氧化酶活力及线虫寿命等为指标,评价桉叶多酚提取物的抗氧化能力。结果表明,桉叶多酚提取物具有良好的自由基清除能力和还原能力,在一定质量浓度下效果接近抗坏血酸。桉叶多酚提取物能显著提高氧化损伤RAW264.7巨噬细胞内抗氧化酶（超氧化物歧化酶、过氧化氢酶）活力和谷胱甘肽含量,并显著降低丙二醛含量（P＜0.05）,呈量效关系。此外,桉叶多酚提取物显著降低常规培养和氧化损伤条件下线虫体内活性氧积累量（P＜0.05）,提高线虫抗氧化能力,起到延长线虫寿命的作用。桉叶多酚提取物在体内外均表现出良好的抗氧化活性,具备开发食品抗氧化剂或功能食品的潜力。