Purification of specularite by centrifugation instead of flotation to produce iron oxide red pigment

This study used specularite, a high-gradient magnetic separation concentrate, as a raw material in reverse flotation.An iron concentrate with a grade of 65.1 wt% and a recovery rate of 75.31% were obtained.A centrifugal concentrator served as the deep purification equipment for the preparation of iron oxide red pigments, and its optimal rotating drum speed, feed concentration, and other conditions were determined.Under optimal conditions, a high-purity iron oxide concentrate with a grade of 69.38 wt% and a recovery rate of 80.89% were obtained and used as a raw material for preparing iron oxide red pigment.Calcining with sulfuric acid produced iron red pigments with different hues.Simultaneously, middlings with a grade of 60.20 wt% and a recovery rate of 17.51% were obtained and could be used in blast furnace ironmaking.High-value utilization of specularite beneficiation products was thus achieved.

Research and Development of Cadmium Sulphoselenide Red Pigment

Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insuffi cient encapsulation effi ciency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required fi ne size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.

Preparation of SiO_2 coated Ce_2S_3 red pigment with improved thermal stability

SiO2 coated Ce2S3 red pigment was prepared in ethanol/H2O system via sol-gel method and TEOS were used as silica sources. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX）, UV-visible spectro-photometer and automatic colorimeter were used to investigate the properties of the samples. The results showed that the compact SiO2 film formed on the surface of Ce2S3 pigment at a cerium silicon molar ratio of 2. The thermal stability temperature of Ce2S3 pigment was improved to 450 oC after SiO2 coating. In addition, the color of Ce2S3 pigment was not affected significantly through coating colorless and transparent SiO2 and it could be used as safe red pigment in higher temperature fields.

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxides

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxide Ca3(Bi1-xREx)8O15(0≤x≤0.09;RE=Sc^(3+),Er^(3+),Y^(3+),Ho^(3+)and Dy^(3+)),were successfully synthesized and the color properties were characterized.The color of these pigments depended on the composition and the synthesis condition,and the most vivid red color was obtained for the Ca3(Bi0.93Y0.07)8O15 sample calcined thrice at 800℃for 2 h.The L*and a*values corresponding to brightness and red chromaticity for this pigment were 45.6 and+30.6,respectively,which were greater than those of a commercially available Fe2O3 pigment(L^(*)=38.4,a^(*)=+29.5).Since the present pigment is composed of nontoxic and safe elements,it should be an attractive alternative to the conventional Fe2O3 pigment.

Effect of Sr^2+ and Dy^3+ co-doping on coloration and temperature stabilization of a γ-Ce2S3 red pigment

In this paper,a Sr^2+and Dy^3+co-doped γ-Ce2S3 red pigment was synthesized via a combination of coprecipitation and sulfurization processes.Mixed oxide was prepared by presintering the coprecipitates,(Ce,Sr,Dy)CO3,followed by high-temperature sulfurization under a CS2 atmosphere.The effects of the sulfurization temperature,time,and doped proportion on the phase composition,color performance and temperature stability of γ-Ce2S3 were systematically studied.The results show that a stable γ-Ce2S3 red pigment can be obtained through Sr^2+and Dy^3+co-doping at 730℃ for 200 min.The diffraction peaks of all the samples shift to higher 2θ values with increasing doping proportion,indicating that part of the Dy^3+species enter the lattice and form a solid solution.The band gap of the samples remains practically constant at 2.01-2.04 eV,which causes their red color.The best red-color quality(L*=37.13,a*=34.77,b*=29.44) is achieved when the pigment has a Dy^3+/Ce^3+molar ratio of 0.15,and the material maintains its excellent red color(L*=31.49 a*=30.94 b*=25.33) after being heated at 410℃ for 30 min.

Determination and thermal stability experiments of red pigment from large-scale silver deposit hosted in the Sinian strata in South China and their significance

Over the past years a kind of red organic pigment was found in various strata in Chi-na. Recently, the authors have discovered the similar red pigment in a large-scale sil-ver deposit hosted in the Sinian black shale, and confirmed that the pigment is an

Preparation of Cr-Doped YAlO3 Red Ceramic Pigment and the Coloration Mechanism

The red ceramic pigment is widely used in industrial production, but the pigments with pure color and bright red performance are rare. Therefore, it is important to study and develop new red ceramic pigment with perfect color performance. This paper reports the preparation of Cr-doped YAlO_3 red ceramic pigment rendering by sol-gel method with high temperature resistance, good color and proposed color mechanism. The prepared samples were characterized by XRD, SEM, EDS and UV-vis, and the effects of Cr on the crystal structure, color rendering properties and color mechanism were discussed. The results showed that the optimum concentration of coloring agent（Cr） in Cr：YAlO_3 red ceramic pigment was 3 at.%. The main color mechanism was also discussed. Compared with the solid phase sintering and precipitation methods for the synthesis of red ceramic pigment, the sol-gel method possessed obvious advantages, such as perfect mixing of the raw materials, uniform dispersion of doping ions and the pure color.

High-Efficiency Synthesis and Properties of Latent Pigment Red 272DPP-BOC by Microwave Irradiation

A high-efficiency synthesis method for a latent pigment of red pigment diketo-pyrrolo-pyrrole (Pig. Red 272:272DPP), which is important as a functional organic pigment, was investigated, and the investigation results revealed that irradiation of microwaves (MWs) for several seconds to 272 DPP in NMP (N-methyl-2-pyrrolidone) solvent yielded DPP latent pigment (272DPP-BOC) at a high yield of 86.2%. Two kinds of latent-pigment crystals, namely, red and yellow, were obtained by recrystallization, and it was found that the fluorescence-emission properties of the two kinds differ significantly. Single-crystal X-ray structural analysis showed that the difference in the fluorescence-emission properties of the two types is derived from the difference in their crystal structures.

Study on the Stability of Pigment in Red Pulp Plum

The stability was studied of the pigment in red pulp plum (Prunus salicina Lindl). The results showed that the pigment had a high resistance to heat and it′s stability seemed to be affected greatly by pH, and red pulp plum was suitable to be applied for making acid food. Several kinds of metallic ions including Na + 、Zn 2+ had an effect of reinforcement on its tone, however Fe 3+ had a disruptive effect. Sucrose had no undesirable effect, but vitamin C had a significant undesirable effect. Also the preservative of sodium benzoate had a definite undesirable effect. The pigment showed strong resistance to reducer sodium sulfite but was very weak in resistance to oxidizer hydrogen peroxide.

索氏抽提法制备裂果枣红色素及其理化性质分析

以裂果枣粉为原料,采用索氏抽提法对裂果枣红色素进行提取,分别采用单因素试验和响应面试验进行提取条件的优化,并对裂果红枣色素进行理化性质研究(抗氧化活性及色素稳定性)。结果表明:索氏抽提法提取最佳条件为裂果枣粉添加量2.0 g/100 mL、乙醇体积分数69%、加热温度89℃、浸提时间26 min、抽提时间1.5 h,裂果枣红色素提取率4.540 mg/g,裂果枣红色素提取率较高。通过研究裂果枣红色素对DPPH自由基,·NO_(2)^(-)和ABTS+自由基的清除能力,结果显示裂果枣红色素浓度达到1.2 mg/mL时,DPPH自由基清除率可达67.8%,当裂果枣红色素浓度达到2.0 mg/mL时,NO_(2)^(-)清除率为69.4%,当裂果枣红色素浓度达到1.5 mg/mL时,ABTS^(+)自由基清除率达到63.5%。裂果枣红色素稳定性试验结果表明,索氏抽提法提取的裂果枣红色素具有良好的热稳定性,光照对其稳定性有一定的影响,pH值对裂果枣红色素稳定性的影响较大。

Culture medium optimization for pigment production with RSM method

Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain （Flavobocterium sp.）. In the first optimization step the influence of yeast extract, peptone, glucose and sodium chloride on pigment production was evaluated using a fractional factorial design. Pigment production was positively influenced by glucose and sodium chloride while other components had no significant effect. In the second step the path of steepest ascent was used to approach the optimal region of the medium composition. In the third step the optimal concentration of glucose and sodium chloride was determined by a central composite design and response analysis. The optimized medium allowed pigment production （A 535-650） to be increased from 0.137 to 0.559, being 320% higher than the original medium.

火龙果果皮红色素抑菌活性及对鳙鱼肉新鲜度的指示效应

本研究通过超声波辅助乙醇浸提法提取火龙果果皮红色素,采用药敏试纸抑菌圈检验法、DPPH自由基清除法比较两种果皮红色素的抑菌活性和总抗氧化能力,同时结合果皮红色素提取物对pH变化的响应和色差值评估指标,优选红色素提取物浓度制作指示卡。通过检测常温放置过程中鱼肉的pH、脂质过氧化值变化评估指示卡对鳙鱼鱼肉新鲜度的指示效果。结果表明,红肉红皮火龙果果皮红色素对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑菌活性和总抗氧化能力均显著高于白肉红皮火龙果果皮红色素(P<0.05),且其红色素提取物水溶液对pH2~13具有较灵敏的呈色变化反应。应用10 g/L红肉火龙果果皮红色素提取物制备的指示卡,评估鳙鱼鱼肉变化可知,25℃常温放置12 h过程中鱼肉的pH先微降后上升,TBA脂质过氧化值持续升高为0 h的1.96倍,揭示鱼肉的新鲜度下降;同期,放置鱼肉的指示卡色差值ΔE也从起始时1.40(0 h)上升到18.30(12 h),指示卡外围呈色从淡红色向玫红色及土黄色转变,对放置的鲜切鳙鱼肉新鲜度的衰减表现出较为直观的指示效应。本研究为火龙果果皮天然红色素的综合利用提供前期的科学依据,也为水产类预制菜行业的新型食品包装应用提供初步参考。

香樟树红叶色素的提取及稳定性研究

以香樟树红叶为原料,采用溶剂浸提法提取香樟树红叶色素。以色素特征吸光度为指标,研究红叶色素的提取工艺和稳定性。结果表明:最佳提取工艺为料液比1:40(g/mL)、乙醇体积分数40%、提取温度70℃、提取时间2.5h。稳定性试验得出,在较低温度(20~60℃)、避光条件下,红叶色素的稳定性较好;红叶色素在酸性、中性和弱碱性(pH1~9)条件下稳定,在强碱性(pH10~14)条件下不稳定;红叶色素具有较好的抗氧化性和抗还原性;冰醋酸对红叶色素的稳定性影响不大,而葡萄糖对其有一定影响;金属离子Fe^(2+)、Fe^(3+)、Cu^(2+)Pb^(2+)对红叶色素的稳定性影响明显。通过显色反应得出香樟树红叶色素主要含有二氢黄酮醇类物质。

Construction of high-density genetic linkage map of Pyropia yezoensis(Bangiales,Rhodophyta)and identifi cation of red color trait QTLs in the thalli

Pyropia yezoensis is an important macroalga because of its extensive global distribution and economic importance.Color is an important trait in the thalli of P.yezoensis,it is also an effective marker to identify the hybridization in genetic breeding.In this study,a high-density genetic linkage map was constructed based on high-throughput single nucleotide polymorphism(SNP)markers,and used for analyzing the quantitative trait loci(QTLs)of red color trait in the thalli of P.yezoensis.The conchospore undergoes meiosis to develop into an ordered tetrad,and each cell has a haploid phenotype and can grow into a single individual.Based on this theory,F1 haploid population was used as the mapping population.The map included 531 SNP markers,394.57 cM long on average distance of 0.74 cM.Collinear analysis of the genetic linkage map and the physical map indicated that the coverage between the two maps was 79.42%.Furthermore,QTL mapping identified six QTLs for the chromosomal regions associated with the red color trait of the thalli.The value of phenotypic variance explained(PVE)by an individual QTL ranged from 4.71%-63.11%.And QTL qRed-1-1,with a PVE of 63.11%,was considered the major QTL.Thus,these data may provide a platform for gene and QTL fine mapping,and marker-assisted breeding in P.yezoensis in the future.

色素通路相关基因在红背和黑背中华蜜蜂成年工蜂背板中的表达模式分析

【目的】分析红背中华蜜蜂Apis cerana cerana色素通路相关基因的表达差异,揭示红背中华蜜蜂色素形成的分子机制。【方法】采用体视显微镜观察刚出房红背中华蜜蜂和黑背中华蜜蜂(正常个体)成年工蜂的体色差异。通过同源比对鉴定中华蜜蜂成年工蜂黑色素代谢通路相关8个基因(PAH,TH,DDC,ebony,tan,aaNAT,yellow-y和laccase 2)、蝶呤通路相关4个基因(GTPCH I,SPR,PTPS和GC-1)、眼色素通路相关2个基因(vermilion和cinnabar)以及尿酸盐转运相关4个基因(BLOS2,HPS5,OK和Varp)的同源基因;运用荧光定量PCR检测上述色素通路相关基因在红背中华蜜蜂和黑背中华蜜蜂成年工蜂胸部背板和腹部体壁中的相对表达量。【结果】红背中华蜜蜂和黑背中华蜜蜂成年工蜂体色差异表现在胸部背板:红背中华蜜蜂胸部背板呈现棕红色,黑背中华蜜蜂胸部背板则为黑色。荧光定量PCR检测结果表明,胸部背板中tan,laccase 2,SPR,vermilion,cinnabar,BLOS2和OK的表达量以及腹部体壁中OK的表达量在红背中华蜜蜂成年工蜂与黑背中华蜜蜂成年工蜂间有显著性差异。【结论】红背中华蜜蜂和黑背中华蜜蜂明显的体色差异位于胸部背板,这种体色分化的现象受到蜜蜂体内黑色素、蝶呤、眼色素通路及尿酸盐转运相关基因共同作用的影响。

饼干中紫草红色素检测方法的建立

建立了高效液相色谱法测定饼干中紫草红色素含量的分析方法。饼干样品经甲醇超声提取后定容上机,采用Agilent ZORBAX Eclipse XDB-C_(18)色谱柱,以甲醇——0.1%甲酸=85∶15(V/V)为流动相,采用二极管阵列检测器,波长为516 nm,柱温35℃,等梯度洗脱。结果表明,在该色谱条件下紫草红色素在0.5~100.0μg/mL范围内呈良好线性关系,相关系数大于0.9999,方法检出限为0.2 mg/kg,平均加标回收率为88.1%~96.7%,相对标准偏差(n=6)为2.7%~5.8%。该方法样品前处理简单高效、加标回收率高、检出限低、精确度高,能够较准确地对饼干中紫草红色素进行定量测定。此检测方法的建立为食品中的紫草红色素的定量检测提供了一定的理论参考。

Preparation of Novel Scorzalite Imitated Phosphate Pigments

Novel phosphate pigments imitated with Scorzalite,FeAl2(PO4)2(OH)2,were prepared from iron and aluminum nitrate solutions,ascorbic acid,and phosphoric acid with pH adjustments(pH 5,7,9).The obtained precipitates were heated at 300,500,and 700°C for 1 h.The precipitates and their thermal products were estimated with X-ray diffraction(XRD),Infrared(IR)spectra,ultraviolet-visible(UV-Vis)reflectance spectra,and L*a*b*color space.The precipitated sample was not clearly colored,but it turned orange to red when heated.Samples prepared at low pH showed higher whiteness than samples prepared at high pH.The theoretical amount of ascorbic acid was sufficient to completely reduce iron during the adjustment.This study showed the possibility of novel inorganic phosphate red pigment.

外源多酚添加条件下干红葡萄酒颜色和花色苷特性研究

颜色是红葡萄酒重要的感官特征和质量评价指标,花色苷是红葡萄酒呈色、稳定和营养功能的重要物质基础。既往研究极少探讨外源添加天然色素对红葡萄酒颜色质量和花色苷的影响。选取赤霞珠干红葡萄酒为研究对象,于酒精发酵前和发酵后分别添加天然色素Ⅰ和天然色素Ⅱ2种色素,并以添加黄岑苷、绿原酸和没食子酸3种多酚为对照,探究对葡萄酒颜色特征、花色苷种类与含量的影响。结果发现:在发酵前添加天然色素Ⅰ和Ⅱ使得酒体颜色加深、红色色调加强、花色苷含量增加。在发酵后添加以上多酚对葡萄酒颜色和花色苷的影响弱于发酵前添加,但添加天然色素Ⅰ仍然有利于花色苷含量的保持,只是效果弱于发酵前添加。其余多酚物质处理对供试酒样颜色品质影响较小。研究结果表明发酵前添加多酚物质更有利于红葡萄酒颜色品质的提升和稳定、花色苷含量的保持和稳定,天然色素Ⅰ是相对最优质的辅色剂。

发酵法脱除萝卜红色素异味的菌种筛选

为解决萝卜红色素中含有异味的问题,以萝卜红色素为研究对象,以感官评分和萝卜红色素含量为指标,筛选出能有效脱除萝卜红色素中异味的菌株,并优化发酵条件。结果表明,脱味效果较佳的4株菌,分别为酿酒酵母、黑曲霉、米曲霉和米根霉,最佳质量比为2∶2∶1∶0;最佳发酵条件为发酵时间60 h、发酵pH5.0、发酵温度30℃、复配菌种接种量2%。在该条件下,萝卜红色素的感官评分为8.70±0.07,萝卜红色素的提取量为0.022 mg/g。