荞麦生物类黄酮研究现状

本文总结荞麦生物类黄酮化学组成、功能特性研究现状,介绍荞麦黄酮提取工艺概况,并 对荞麦生物类黄酮的开发与利用进行展望。     

生物类黄酮的研究与应用概况

介绍了生物类黄酮的结构与生物活性的关系、生物类黄酮的提取、精制、鉴定方法及应用，旨在为生物类黄酮的研究、开发、应用提供参考。     

生物类黄酮提取方法的研究分析

所谓的生物类黄酮就是指维生素P,是一种植物的次级代谢产物,不是某一种单一的化合物,而是某一类具有相同或相似结构及活性的物质总称。生物类黄酮在抗氧化、抗血栓、保护心脑血管等方面有着良好的表现,故一直深受人们重视,对其研究工作也一直在进行,目前,生物类黄酮的提取主要有有机溶剂萃取法、醇提取、酶法、碱性水或碱性稀醇提取法及超临界萃取法等方法。     

柑橘类黄酮的生理活性和研究进展

生物类黄酮(bioflavonoid)是一类植物次级代谢产物,在自然界中广泛存在,尤其在各种蔬菜、水果和谷物之中含量丰富。近年的研究表明,柑桔果实也是生物类黄酮的重要来源。检测来自中国的10个柑桔品种的     

荞麦制品感官分析及香气成分研究进展

荞麦营养丰富,富含芦丁等生物类黄酮化合物,是生产功能性食品的重要原料,但因其特有的苦涩味造成产品口感较差,对荞麦产品的开发带来一定的负面影响。该文综述各种荞麦产品的感官评价和挥发性成分的研究进展,以期为荞麦产品的进一步优化提供参考。     

柚皮中生物类黄酮提取优化工艺研究

在初选溶剂的基础上,对柚皮中生物类黄酮提取进行正交试验优化工艺研究,以提取温度、提取时间、乙醇浓度、固液比为因素,选用L16(44)正交表进行试验。结果表明,优化工艺条件是:温度为60℃,提取时间为1h,浓度为85%,固液比为1∶30。在此条件下,生物类黄酮提取含量较高,可达24.00(mg/g)。     

荞麦治疗糖尿病化学成分的研究进展

荞麦是一种粮药兼备的粮食作物,目前世界上有多个国家传统食疗研究都发现食用荞麦可降血糖,因此荞麦可用于中药治疗糖尿病。通过现代生化与分子生物学、细胞生物学等研究手段已经逐渐确定荞麦中起降血糖作用的化学成分及其可能作用途径,降糖成分主要是植物肌醇、生物类黄酮以及荞麦蛋白。分离鉴定荞麦降糖成分可以为研究开发荞麦源糖尿病药物提供思路,亦能为加工生产荞麦功能性食品提供参考信息。本文主要综述了国内外关于荞麦降糖化合物的研究进展,并对其可能作用机制进行了初步讨论。     

芬芳的礼物

生物类黄酮是广泛分布于植物中的一大类衍生化合物,目前已知的类黄酮化合物已有一千多种.它们包括黄酮、黄酮醇、异黄酮、黄烷酮、查耳酮、花色素、色原酮等,其中食品中的主要类黄酮有黄烷酮、黄酮、黄酮醇和异黄酮四类.生物类黄酮具有生物活性和生理作用,特别是其抗氧化、抗自由基及抗癌、防癌的作用.因此,如何有效地提取和分离提纯生物类黄酮对其开发应用越来越关键.     

紫茎女贞老叶生物类黄酮提取工艺研究

通过实验确定紫茎女贞老叶生物类黄酮的提取工艺为:以乙醇浓度60%为溶剂,料液比1:20,在95℃回流浸提2 h;将提取液浓缩、离心、干燥得黄酮粗粉(得率5.95%,总黄酮含量22.5%)和黄酮浸膏(得率2.37%,总黄酮含量19.6%),可作为天然添加剂广泛应用于食品、药品、化妆品生产.     

保健功能因子—生物类黄酮

生物类黄酮具有多种多样生物活性和药理作用,如抗癌、抗过敏、抗炎症等功效;该文主要论述 生物类黄酮对人体几种主要保健功能及其在一些食品中来源。     

Invited review: Phenotypes to genetically reduce greenhouse gas emissions in dairying

Phenotypes have been reviewed to select for lower-emitting animals in order to decrease the environmental footprint of dairy cattle products. This includes direct selection for breath measurements, as well as indirect selection via indicator traits such as feed intake, milk spectral data, and rumen microbial communities. Many of these traits are expensive or difficult to record, or both, but with genomic selection, inclusion of methane emission as a breeding goal trait is feasible, even with a limited number of registrations. At present, methane emission is not included among breeding goals for dairy cattle worldwide. There is no incentive to include enteric methane in breeding goals, although global warming and the release of greenhouse gases is a much-debated political topic. However, if selection for reduced methane emission became a reality, there would be limited consensus as to which phenotype to select for: methane in liters per day or grams per day, methane in liters per kilogram of energy-corrected milk or dry matter intake, or a residual methane phenotype, where methane production is corrected for milk production and the weight of the cow. We have reviewed the advantages and disadvantages of these traits, and discuss the methods for selection and consequences for these phenotypes.     

面包专用粉试验方法的研究

烘焙试验是检验面包专用粉操作性能和食用品质最直接、最有效的方法。因此,立足烘焙试验,从面包的制作工艺和品种入手,发现在面包的制作过程中将盐、糖和酵母分别溶解依次加入面粉,对面包的质量及试验结果至关重要。在试验品种方面,主食面包最易区分面包的结构层次;无盖土司最能反映面包的体积和外在质量;圆形面包则可检验面包粉拉力比数的适宜程度,表明面团的耐搅拌、耐醒发及持气能力的大小。     

HPLC内标法测定啤酒中氨基酸含量的研究

采用邻苯二甲醛 (OPA) - 9-芴甲基氯甲酸酯 (FMOC)进行氨基酸柱前衍生 ,反相高效液相色谱测定氨基酸含量。并采用正缬氨酸 (NVAL)和肌氨酸 (SAR)分别作为一级氨基酸和二级氨基酸的内标物 ,从而校准和消除了由于操作条件的波动而对分析结果产生的系统误差。结果表明 :三个不同浓度梯度的氨基酸标准溶液线性关系良好 ;样品保留时间绝对误差小于 0 .1min ,重现性RSD值低于 4 % ;加标回收率均在 90 %～110 %之间 ,说明该分析方法准确、可信并具有较高的灵敏度     

类金刚石涂层处理转杯、分梳辊的探讨

为提高转杯纺纺纱元件的耐磨性，做了分梳辊齿环气相沉积镀类金刚石涂层（DLC）试验，结果证明，类金刚石膜硬度可以达到1500HV～2000HV；摩擦系数为0．10～0．25；附着力为53．6N。通过纺纱试验证实纺纱质量略有提高，能满足纺纱工艺要求，值得进一步探讨。     

Crosslinking in polysaccharide and protein films and coatings for food contact – A review

BackgroundCrosslinking is the process of forming tridimensional networks by linking polymer chains by covalent or noncovalent bonds. It is useful for polysaccharide- and protein-based films and coatings to be applied to food surfaces, enhancing their water resistance as well as mechanical and barrier properties. Crosslinkers intended to be used for food contact materials must present low toxicity.Scope and approachThis review is a summary of the main crosslinking agents which have been used for protein and polysaccharide films and coatings, and which may be applied as food contact materials. The study emphasizes the mechanisms of crosslinking agents, the chemical groups involved, conditions for application, advantages and drawbacks, as well as examples of applications for food contact materials.Key findings and conclusionsCrosslinking is a promising technique to improve the performance and applicability of protein- and polysaccharide-based food contact materials, especially concerning their water sensitivity, which hinders many of their potential applications as food contact materials. Some aldehydes are very effective as crosslinkers, but they have been avoided in food contact materials because of possible migration of aldehyde residues to food, and less toxic compounds have been studied for those applications, such as phenolic acids, oxidized polysaccharides, and enzymes. Crosslinking techniques may help make protein- and polysaccharide-based materials more suitable for large-scale processing and applications in the future.     

International legislation on trace elements as contaminants in food: a review

Environmental contaminants such as trace elements may be present in all foods. Foods, raw materials and ingredients for food production are to an increasing extent traded across borders. Hence, there is a need for international legislation on trace elements as contaminants in food. In 1961, the FAO and WHO established the Codex Alimentarius to elaborate international food legislation. Contaminants in food are handled by the Codex Committee for Food Additives and Contaminants (CCFAC). The Codex Alimentarius system for developing legislation concerning trace elements as contaminants in food is based upon the Codex General Standard for Contaminants and Toxins in Food (GSCTF). By October 2001, the principles for setting maximum limits (MLs) for contaminants in food are agreed, and work is in progress on MLs for trace elements such as lead and cadmium in the various food categories. The status for the proposals is presented and discussed. The EU Regulation 466/2001 of 8 March 2001 sets MLs for lead and cadmium in various foods. This regulation will apply from 5 April 2002. The EU regulation is more detailed but similar to the Codex draft standards for lead and cadmium in food. In future, legislators and administrators in the Codex and EU and analytical chemists will discuss how to use more and better analytical data as risk-management tools to protect public health. Trace elements' speciation is an important aspect of this discussion.     

β‐Carotene as a Membrane Antioxidant Probed by Cholesterol‐Anchored Daidzein

β‐Carotene is found to be more effective as an antioxidant in phosphatidylcholine (PC) liposomes when protecting against hydrophilic radicals compared to lipophilic radicals, as measured by the rate of formation of conjugated dienes. Daidzein alone is without effect, but decreases the antioxidative effect of β‐carotene for hydrophilic initiation and increases the effect for lipophilic initiation. The newly synthesized 7‐cholesterylglycol daidzein has the opposite effect for β‐carotene as antioxidant, with a strong enhancement for hydrophilic initiation and a slight decrease for lipophilic initiation. Redistributing β‐carotene to membrane surfaces by cholesterol‐anchoring of daidzein enhances protection against aqueous radicals significantly at the expense of protection against lipid‐derived radicals. Anchoring of daidzein to cholesterol is concluded to be useful as a mechanistic tool for controlling antioxidant distribution in membranes sensitive to radical damage, as supported by quantum mechanical calculation within the density function theory and further supported by fluorescence probes and fluorescence polarization probes.     

ADSA Foundation Scholar Award: defining dairy flavors

Production and consumption of dairy foods continue to increase annually. Further, new ingredient applications for dairy foods continue to expand. With continued production and consumption, there is also increased competition. Increased competition exists regionally, nationally, and globally. Processors as well as product developers must find ways to maximize existing markets and expand into new markets. A consistent high quality product is necessary to maintain competitiveness. Although microbial safety and stability are key ways to define quality, flavor is one method of defining quality that is often assumed or overlooked. The aggressive and competitive nature of today's market demands more precise and powerful tools for defining flavor and flavor quality. Traditional as well as more recent methods for evaluating dairy flavor are reviewed. The application of defining sensory flavors to fundamental research on flavor chemistry, product understanding, and effective marketing is addressed.     

锦棉交织物前处理工艺初探

采用传统的全棉煮漂一浴法和改进的煮漂一浴法,以及精练酶煮漂一浴法对锦棉交织物进行前处理,测试了半制品的手感、白度、毛效及弹性.结果发现,传统的前处理采用高温强碱,对锦纶的损伤较大;采用Na2CO3取代NaOH煮练,效果较佳;生物酶煮练则使用助剂少,对锦纶损伤低,效果佳,且对环保有利.     

Biovanillin from agro wastes as an alternative food flavour

This review provides an overview of biovanillin production from agro wastes as an alternative food flavour. Biovanillin is one of the widely used flavour compounds in the foods, beverages and pharmaceutical industries. An alternative production approach for biovanillin as a food flavour is hoped for due to the high and variable cost of natural vanillin as well as the limited availability of vanilla pods in the market. Natural vanillin refers to the main organic compound that is extracted from the vanilla bean, as compared to biovanillin, which is produced biologically by microorganisms from a natural precursor such as ferulic acid. Biovanillin is also reviewed as a potential bioflavour produced by microbial fermentation in an economically feasible way in the near future. In fact, we briefly discuss natural, synthetic and biovanillin and the types of agro wastes that are useful as sources for bioconversion of ferulic acid into biovanillin. The subsequent part of the review emphasizes the current application of vanillin as well as the utilization of biovanillin as an alternative food flavour. The final part summarizes biovanillin production from agro wastes that could be of benefit as a food flavour derived from potential natural precursors.© 2012 Society of Chemical Industry