苋菜红色素提取工艺的研究进展

从苋菜中提取的色素是一类重要的绿色天然色素,可取代对人体健康有危害的合成色素。本文简要介绍了苋菜红色素的性质与应用,综述了其近年来提取工艺的研究进展状况,并展望了苋菜色素的发展前景。     

籽粒苋蛋白质功能特性的研究(I)——籽粒苋蛋白质乳化性、持水力的研究

采用碱性提取和等电点法分离出籽粒苋蛋白质,测定了不同浓度、pH值、离子强度、蔗糖浓度条件下的蛋白质乳化能力、乳化稳定性、持水力,探讨了籽粒苋蛋白质在不同条件下乳化性和持水力的变化规律,为籽粒苋蛋白质在食品加工中的应用提供了一定的理论依据。     

Seed-germination inhibition by volatile alcohols and other compounds associated withAmaranthus palmeri residues

Effects of 3-pentanone and eight low molecular weight aliphatic alcohols and aldehydes identifed in the mixtures of volatiles released byAmaranthus palmeri S. Wats. (AMAPA) residues were determined on germination of onion, carrot, AMAPA, and tomato seeds. Three-day exposures to these volatiles significantly inhibited germination of these assay seeds, and the inhibition was dependent upon exposure time and concentration. Based on the degree of inhibition observed in both time- and concentration-dependent assays, the following activity series was obtained: 2-heptanol > 3-methyl-1-butanol, 1-hexanol > hexanal, 1-pentanol, 3-pentanone, acetaldehyde > ethanol, 2-methyl-1-propanol. The activities of this group of compounds with that of 2-heptanone appear to be additive and related to test compound volatility and hydrophilicity. 2-Heptanol and 2-heptanone also significantly inhibited the germination of other species, including shepherdspurse, soybean, lettuce, alfalfa, common purslane, oats, and lovegrass.Name of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.     

胭脂红和苋菜红与石墨烯/CdTe量子点复合物相互作用的对比研究

分别测定了胭脂红和苋菜红与石墨烯/CdTe量子点复合物相互作用的荧光光谱和紫外吸收光谱。研究发现胭脂红和苋菜红均对石墨烯/CdTe量子点复合物具有较强的荧光猝灭作用,且均为静态猝灭过程。但是由于结构上的差异,所引起的石墨烯/CdTe量子点复合物荧光猝灭率有所不同。通过变温实验、紫外吸收光谱和结构分析,得出胭脂红引起的石墨烯/CdTe量子点复合物的猝灭率更高。研究还发现,胭脂红和苋菜红的浓度与石墨烯/CdTe量子点复合物荧光强度的降低之间均存在良好的线性关系,可分别用于胭脂红和苋菜红的定量分析。     

Physiological and Molecular Analysis of Aluminium-Induced Organic Acid Anion Secretion from Grain Amaranth (Amaranthus hypochondriacus L.) Roots

Grain amaranth (Amaranthus hypochondriacus L.) is abundant in oxalate and can secrete oxalate under aluminium (Al) stress. However, the features of Al-induced secretion of organic acid anions (OA) and potential genes responsible for OA secretion are poorly understood. Here, Al-induced OA secretion in grain amaranth roots was characterized by ion charomatography and enzymology methods, and suppression subtractive hybridization (SSH) together with quantitative real-time PCR (qRT-PCR) was used to identify up-regulated genes that are potentially involved in OA secretion. The results showed that grain amaranth roots secrete both oxalate and citrate in response to Al stress. The secretion pattern, however, differs between oxalate and citrate. Neither lanthanum chloride (La) nor cadmium chloride (Cd) induced OA secretion. A total of 84 genes were identified as up-regulated by Al, in which six genes were considered as being potentially involved in OA secretion. The expression pattern of a gene belonging to multidrug and toxic compound extrusion (MATE) family, AhMATE1, was in close agreement with that of citrate secretion. The expression of a gene encoding tonoplast dicarboxylate transporter and four genes encoding ATP-binding cassette transporters was differentially regulated by Al stress, but the expression pattern was not correlated well with that of oxalate secretion. Our results not only reveal the secretion pattern of oxalate and citrate from grain amaranth roots under Al stress, but also provide some genetic information that will be useful for further characterization of genes involved in Al toxicity and tolerance mechanisms.     

鸡冠花红褪色光度法测定羟自由基

研究了以食用色素-鸡冠花红为指示,氧化褪色光度法测定Fenton反应产生的羟自由基.在硫酸介质中,羟自由基能够氧化鸡冠花红褪色,在520nm波长处测定吸光度值的变化,可间接测定羟自由基的量.该法所用仪器简单,试剂廉价易得,操作简便,稳定性好,可作为一种筛选羟自由基清除剂的方法.     

Identification of volatile allelochemicals fromAmaranthus palmeri S. Wats

Allelopathic volatiles associated with the weed Palmer amaranth (Amaranthus palmeri S. Wats.; AMAPA) were trapped on Tenax GC, thermally desorbed, and identified by gas chromatography-mass spectroscopy. Methyl ketones and alcohols (C₄–C₁₁) were the principal components of the volatiles mixture. Seedheads, stems, or roots were placed in a glass container and incubated at 31 °C (10 hr)/21 °C (14 hr) for three days prior to trapping the volatiles. Seedheads were rich in 2-heptanone which was consistently found, together with 2-heptanol, in all AMAPA tissues. Vapors of authentic 2-heptanone and (±)-2-heptanol at concentrations of 1 ppm or higher strongly inhibited the germination of onion and carrot and almost completely suppressed the germination of tomato and AMAPA seeds.Names of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.     

介孔TiO2对饮料中4 种色素在太阳光下的光催化降解

以日落黄为模板,四异丙醇钛为原料合成介孔二氧化钛（MTiO2/SY）,在太阳光下对含有日落黄、柠檬黄、苋菜红、胭脂红等4 种色素的饮料进行光催化实验,通过进行X射线衍射（X-ray diffraction technique,XRD）、N2等温吸附-解吸和紫外-可见漫反射光谱表征。结果表明,MTiO2/SY具有介孔孔道结构,较大的比表面积和可见光区吸收,在太阳光下对饮料中日落黄、柠檬黄、苋菜红、胭脂红有较强的光催化降解活性,太阳光下光催化活性明显高于P25。光催化降解后的饮料可以进行自然排放,但不宜食用。     

红薯叶苋菜复合饮料的研究

通过对红薯叶和苋菜原料配比、浸提条件、护色、调配等的研究，选择出最佳实验配比方案；红薯叶：苋菜为4：3，红薯叶浸提时间为3h，苋菜浸提时间为2h，柠檬酸为0．01％，蔗糖为7．0％，抗异坏血酸钠为0.2％。最终生产出了色、香、味俱佳的具有保健功能的天然红薯叶苋菜复合饮料。