微波真空干制加工对荷叶茶酚类物质含量及其抗氧化活性的影响

干制脱水加工被广泛应用于农副产品的保藏和精深加工,但是干制加工会影响产品活性物质的含量,导致其生物活性发生改变。为了研究微波真空干制功率对荷叶酚类物质的影响,比较了300,400,500 W等不同微波功率真空干制及热风干燥、日晒条件下,荷叶酚类物质含量变化;采用DPPH和FRAP方法比较不同微波功率产品的抗氧化活性差异。结果表明,荷叶经微波真空干制加工后,总酚和总黄酮含量较热风干燥法显著提高,分别是后者的1.79和1.76倍;荷叶提取物抗氧化活性显著提高,微波真空干制荷叶清除DPPH·活性优于热风干燥方式,300,400,500 W微波功率干制荷叶清除DPPH·IC50值分别是62.52,49.31,43.59μg/m L;微波功率500 W干制荷叶提取物FRAP抗氧化活性分别是日晒荷叶和热风干燥荷叶的3.18和1.82倍。抗氧化活性指标与酚类物质含量相关性分析发现,荷叶总黄酮含量与FRAP和DPPH为极显著相关,表明微波真空干制能够显著影响荷叶酚类物质含量,进而增强其抗氧化活性。     

家庭压力烹调对红小豆抗氧化能力的影响

研究家庭压力烹调对红小豆抗氧化成分及抗氧化能力的影响。以常压烹调为对照,检测不同压力和时间烹调后的总多酚、总黄酮含量及DPPH自由基清除能力、铁还原抗氧化能力(FRAP)、氧自由基吸收能力(ORAC)。结果显示:总黄酮、总多酚和3种抗氧化能力指标有较高相关性。与生样比较,各烹调处理的总黄酮、总多酚和各抗氧化能力均有下降。但总体来说,家庭压力烹调对抗氧化物质和抗氧化能力的保存效果并不逊色于常压蒸煮烹调。在包括常压烹调在内的各烹调处理中,122 k Pa/20 min的处理可以最好地保留红小豆中的酚类物质和抗氧化能力。     

烹调对常见蔬菜抗氧化活性与成分的影响

对常见的21种蔬菜,以爆炒、炖煮、微波3种烹调方法处理,采用相关方法测定比较其烹调前后的抗氧化活性,以及VC、总多酚及总类黄酮含量,比较不同烹调方法对蔬菜抗氧化活性及相关物质含量的影响,为评价人群实际抗氧化物质摄入量及相关研究提供参考.结果表明:炖煮导致蔬菜抗氧化活性及相关物质损失较多,微波及爆炒损失较少,且有部分指标出现了增加现象.     

麦类麸皮中酚类物质提取纯化方法的研究进展

麦类麸皮中含有多种酚类物质,主要有酚酸、黄酮、木酚素等。研究表明,这些酚类物质具有良好的抗氧化活性,在食品和医药领域具有广泛的应用前景。该文综述了麦类麸皮中酚类物质提取的研究进展和现状,以期为将来相关产品以及研究提供参考和理论基础。     

生物加工与非热加工对谷物及杂豆酚类物质影响的研究进展

生物加工和非热加工处理在改善谷物及杂豆类食品的食用品质的同时,可显著增加其中酚类物质的含量及抗氧化活性。研究系统综述了生物加工和非热加工对谷物及杂豆酚类物质及其抗氧化活性的影响,并展望今后谷豆加工深入发展的重点探究思路。     

全谷物酚类物质及其抗氧化活性研究进展

近年研究发现全谷物的健康效应与其酚类物质及其抗氧化活性密切相关,而与水果、蔬菜相比,谷物中的酚类物质长期被低估。本文综述了糙米、小麦、玉米和燕麦等主要全谷物中酚类物质的组成、存在形式、含量差异、分布规律及其抗氧化活性,总结不同加工处理对其的影响,分析目前研究的突出问题,展望今后的重点研究方向,为促进全谷物食品的开发利用提供理论依据。     

全谷物酚类物质及其抗氧化活性研究进展

近年研究发现全谷物的健康效应与其酚类物质及其抗氧化活性密切相关,但与水果蔬菜相比,谷物中的酚类物质长期被低估。系统综述了糙米、小麦、玉米和燕麦等主要全谷物中酚类物质的组成、存在形式、含量差异、分布规律及其抗氧化活性,总结了不同加工处理方式对其影响效应,分析了目前研究现存的突出问题并展望下一步的重点研究方向,旨在为促进全谷物食品的开发利用提供理论依据。     

天然防腐剂研究进展

为预防微生物腐败带来的产品品质下降以及对人类健康和世界经济带来不利影响,防腐剂在食品、化妆品、医药等行业得到广泛应用。化学合成防腐剂在安全方面具有局限性,而来源天然的抗菌物质具有安全、稳定、广谱抗菌活性等特点逐步成为研究热点。本文介绍了具有抗菌性的天然防腐剂,包括酚类和非酚类物质。酚类物质具有抗菌、抗氧化、抗褐变、防止酸败等作用,应用更加广泛,而非酚类物质主要表现出抗菌性。     

动物性食品中胆固醇氧化产物的研究进展

动物性食品中的胆固醇氧化产物(Cholesterol Oxidation Products,COPs)的健康效应受到广泛关注。其水平在新鲜动物性食材中均很低,但在储藏加工和家庭烹调中可能有显著增加。文章介绍了水产品、畜产品、蛋制品及乳制品4类食品中影响胆固醇氧化产物形成的因素。研究表明长时间储藏、高温、非适宜的水分活度、与光线和氧气接触等因素均会促进胆固醇氧化产物的形成。烹调中加入油脂的饱和程度和所含抗氧化物质也影响动物性食物烹调后COPs的形成。加入适量的天然抗氧化物质可能有利于减少COPs的生成。     

食品主要成分对微波食品风味的影响

介绍了碳水化合物、蛋白质和脂肪等食品成分对微波食品风味的影响,如碳水化合物中淀粉的螺旋结构对风味化合物的吸收及多糖胶可溶极性风味物质分子的特性,蛋白质随着分子的增大对风味物质的吸收能力也相应提高,脂肪酸败使食品变得苦涩及脂肪氧化可产生强烈的不愉快气味等.用微波烹调食物存在上色不足和风味弱化等问题,可通过直接添加氨基酸及补充一定的糖类,利用美拉德反应来增强微波食品的风味。     

Antioxidant properties of various solvent extracts of potato peel,sugar beet pulp and sesame cake

BACKGROUND: Growing interest in the replacement of synthetic food antioxidants by natural ones has fostered research on vegetable sources and screening of raw materials to identify new antioxidants. The food‐processing industry generates substantial quantities of phenolic‐rich by‐products that could be valuable natural sources of antioxidants. In this study the antioxidant properties and total phenolic, flavonoid and flavonol contents of three industrial by‐products, sugar beet pulp, sesame cake and potato peel, extracted with various solvents were examined. Since different antioxidant compounds have different mechanisms of action, several methods were used to assess the antioxidant efficacy of extracts. RESULTS: Among the six solvents tested, methanol gave the highest extract yield of potato peel and sugar beet pulp, while diethyl ether gave the highest extract yield of sesame cake. Methanol exhibited the highest extraction ability for phenolic compounds, with total phenolics amounting to 2.91, 1.79 and 0.81 mg gallic acid equivalent g^?1 dry weight in potato peel, sugar beet pulp and sesame cake extracts respectively, and also showed the strongest antioxidant capacity in the three assays used. All three methods proved that potato peel extract had the highest antioxidant activity owing to its high content of phenolic compounds and flavonoids. CONCLUSION: On the basis of the results obtained, potato peel, sugar beet pulp and sesame cake extracts could serve as natural antioxidants owing to their significant antioxidant activity. Therefore they could be used as preservative ingredients in the food and/or pharmaceutical industries. Copyright © 2009 Society of Chemical Industry     

The importance of solvent type in estimating antioxidant properties of phenolic compounds by ABTS assay

ABTS assay belongs to the most popular methods employed for estimating antioxidant activity. However, researchers seldom pay attention to specific factors influencing the determination of antioxidant activity of the examined compounds and mixtures. The paper shows that the type of alcohol used significantly influences the estimation of antioxidant activity of phenolic compounds in ABTS assay, namely that their antioxidant activity increase with the lengthening of the aliphatic chain in alcohol. It results rather from the changes in ABTS ^?+ solvatation energy by the employed alcohols than from dissociation variations of phenolic compounds. The obtained results point to the difficulties in the correct estimation of the real antioxidant properties of plant and food extracts by ABTS assay. The presented results have also an ecological implication as they refer to the difference in estimation of antioxidant properties of compounds resulting from the replacement of toxic methanol by GRAS (Generally-Recognized-As Safe) solvents, ethanol and propanol.     

Sorghum Grain: From Genotype,Nutrition, and Phenolic Profile to Its Health Benefits and Food Applications

Globally, sorghum is one of the most important but least utilized staple crops. Sorghum grain is a rich source of nutrients and health‐beneficial phenolic compounds. The phenolic profile of sorghum is exceptionally unique and more abundant and diverse than other common cereal grains. The phenolic compounds in sorghum are mainly composed of phenolic acids, 3‐deoxyanthocyanidins, and condensed tannins. Studies have shown that sorghum phenolic compounds have potent antioxidant activity in vitro, and consumption of sorghum whole grain may improve gut health and reduce the risks of chronic diseases. Recently, sorghum grain has been used to develop functional foods and beverages, and as an ingredient incorporated into other foods. Moreover, the phenolic compounds, 3‐deoxyanthocyanidins, and condensed tannins can be isolated and used as promising natural multifunctional additives in broad food applications. The objective of this review is to provide a comprehensive understanding of nutrition and phenolic compounds derived from sorghum and their related health effects, and demonstrate the potential for incorporation of sorghum in food systems as a functional component and food additive to improve food quality, safety, and health functions.     

Antioxidant activity and antimicrobial effect of berry phenolics--a Finnish perspective

In Finland, berries are part of the traditional diet significantly contributing to the intake of flavonoids and other phenolic compounds. Compositional data on phenolic compounds in berries has been rapidly accumulating and included in the national food composition database. Among the different bioactive substances in berries, phenolic compounds including flavonoids, tannins, and phenolic acids have received considerable interest due to their effects in food and health. A great amount of in vitro evidence exists showing that berry phenolics are powerful antioxidants. However, the antioxidant effect of berry phenolics is strongly dependent on the choice of berry raw material, as the antioxidant activity differs between the different phenolic constituents, including anthocyanins, ellagitannins, and proanthocyanidins. In foods, the antioxidant effect is also influenced by the structure of food. Tannin-containing berries exhibit antimicrobial properties against pathogenic bacteria, thus offering many new applications for food industry. Much of the interest in berry phenolics has focused on cranberries and both cultivated and wild blueberries, although also other berries including black currants, cloudberries, lingonberries, and red raspberries possess promising bioactivities that may have relevance to human health. Antioxidant activity of berry phenolics, in addition to other mechanisms, may contribute to human health, but the possible relationship remains yet to be scientifically substantiated.     

绿茶中多酚物质的抗氧化活性及其在肉制品中的应用研究进展

绿茶自古以来就是人类的重要饮料,在亚洲很多国家广泛饮用并被认为对人体健康具有益处。绿茶酚类化合物作为天然抗氧化剂在食品工业中尤其在肉制品中应用十分广泛且意义重大,加入绿茶提取物产品的抗氧化能力得到有效增强,并且减少了加工和储存保藏期间因氧化反应造成的不良变化,从而延长了保质期。本文首先综述了绿茶中酚类化合物的组成,其次简述了酚类化合物发挥抗氧化活性的抗氧化机制以及其产生的生物活性对人体健康的潜在益处,最后阐述了酚类化合物在肉制品中起到抗氧化、抑菌、护色等作用,并对今后的发展趋势进行了展望。     

A review of methods used for investigation of protein–phenolic compound interactions

Interactions between the different compounds present in foods are common and have influence on the nutritional and functional properties of food products. Among a wide range of these interactions, the formation of complexes between proteins and phenolic compounds seems to be the most important issue. Complexation of the phenolic compounds with proteins can be analysed considering several aspects. These complexes might strongly affect nutritional potential of polyphenols by masking their antioxidant capacity, and on the other hand might have influence on the structure of proteins which may cause their precipitation or decrease susceptibility to digestion. The complexity of protein–phenolic compound interactions is a challenge for food analysts and forced researchers to establish a wide range of analytical methods, allowing determination of complexes formation. The main aim of this review is to give researchers an overview of the currently used methods that can be applied to study the interactions between proteins and phenolic compounds.     

Roasting enhances antioxidant effect of bitter melon (Momordica charantia L.) increasing in flavan-3-ol and phenolic acid contents

Bitter melon (BM, Momordica charantia L) has various biological functions including antidiabetic, anticancer, anti-inflammatory, antiviral, and antioxidant activities. In this study, the antioxidant effects of BM fruits, leaves, stems, and roots after roasting using DPPH, ABTS, reducing power, and ferric reducing/antioxidant power (FRAP) assays were compared. The roasted BM exhibited significantly higher antioxidant activity than unroasted BM in the test methods used. Particularly, the roasted BM roots showed the highest antioxidant activity compared to any other extracts. Antioxidant compounds including flavan-3-ols and phenolic acids increased, whereas flavanols decreased in the BM following roast processing. Moreover, the total phenolic contents and flavan-3-ol and phenolic acid contents were markedly increased, leading to a general increase in antioxidant activities after roasting. These results suggest that the roasting BM extracts could be used as a potential source of natural antioxidants in certain food and medicinal applications.     

Phenolic contents and antioxidant activities of bitter gourd (Momordica charantia L.) leaf, stem and fruit fraction extracts in vitro

Bitter gourd (Momordica charantia L.) has long been regarded as a food and medicinal plant. We investigated the antioxidant activity of the water extract of leaf, stem and fruit fractions by several in vitro systems of assay, namely DPPH radical-scavenging activity, hydroxyl radical-scavenging activity, β-carotene–linoleate bleaching assay, ferric reducing/antioxidant power (FRAP) assay and total antioxidant capacity. Total phenolic content was measured by Folin–Ciocalteu reagent. Identification of phenolic compounds was achieved using HPLC with the UV-diode array detection. The extracts of different fractions were found to have different levels of antioxidant activity in the systems tested. The leaf extract showed the highest value of antioxidant activity, based on DPPH radical-scavenging activity and ferric reducing power, while the green fruit extract showed the highest value of antioxidant activity, based on hydroxyl radical-scavenging activity, β-carotene–linoleate bleaching assay and total antioxidant capacity. The predominant phenolic compounds were gallic acid, followed by caffeic acid and catechin. The present study demonstrated that the water extract fractions of bitter gourd have different responses with different antioxidant methods. Total phenol content was shown to provide the highest association with FRAP assay in this present study (R² = 0.948).     

Potential of Medicinal Plants as Antimicrobial and Antioxidant Agents in Food Industry: A Hypothesis

Many food preservation strategies can be used for the control of microbial spoilage and oxidation; however, these quality problems are not yet controlled adequately. Although synthetic antimicrobial and antioxidant agents are approved in many countries, the use of natural safe and effective preservatives is a demand of food consumers and producers. This paper proposes medicinal plants, traditionally used to treat health disorders and prevent diseases, as a source of bioactive compounds having food additive properties. Medicinal plants are rich in terpenes and phenolic compounds that present antimicrobial and antioxidant properties; in addition, the literature revealed that these bioactive compounds extracted from other plants have been effective in food systems. In this context, the present hypothesis paper states that bioactive molecules extracted from medicinal plants can be used as antimicrobial and antioxidant additives in the food industry.     

Food Phenolics,Pros and Cons: A Review

Phenolic compounds like simple phenols, flavonoids, and phenolic acids are commonly in foods of plant origin. Several studies, including animal and epidemiological investigations, have demonstrated that phenolic compounds in foods possess positive attributes such as anticarcinogenesis, antioxidant potential, antiviral activity, antimicrobial activity, and antimutagenic activity. However, other studies have shown that the same phenolics have negative attributes such as carcinogenic activity and antinutritional activity, as well as imparting negative attributes to foods. This review summarizes the information about food phenolics and presents the most current knowledge with respect to its role in human health, food attributes, and toxicity among others.