Precipitated green pigments: products of chromate postgalvanic waste utilization

The paper reports on obtaining highly dispersed chromium(III) silicates and chromium(III) oxides from postchromating waste by reduction of Cr(VI) to Cr(III) with hydrazine as a reducing agent. Chromium(III) salt solution and sodium silicate or hydroxide solutions have been used to precipitate green pigments (silicates and oxides). The effect of the precipitation parameters on the quality of green pigments obtained has been studied, and the optimum parameters ensuring getting the product of well-developed surface area and possibly lowest diameter of primary particles have been established. The precipitated silicates and oxides have been subjected to physicochemical analysis to determine bulk density; capacities to absorb water, dibutyl phthalate, and paraffin oil; particles size; particle size distribution; and surface morphology of chromium pigment surfaces. The adsorptive properties of the oxide and silicate pigments have also been examined. The XRD analysis documented that the chromium(III) silicate pigments obtained are amorphous. In addition, the pigments have been subjected to a colorimetric appraisal using the CIE L*a*b* color space system. The high-quality green pigments obtained have shown high dispersion, small tendency to agglomerate formation, and repeatable green hue. The parameters of the products are promising for their future technological use.     

核桃青皮中萘醌类色素的提取及稳定性研究

为提高核桃青皮中萘醌类色素的提取率,在酶添加量、超声温度、超声时间、液料比4个单因素实验的基础上,采用响应面法优化酶辅助超声波提取萘醌类色素的工艺条件,并研究了光照、温度、氧化还原剂、金属离子对色素稳定性的影响。结果表明:在酶添加量1.0%,超声时间90 min,超声温度70℃,液料比72∶1（m L/g）的条件下核桃青皮萘醌类色素提取率最高,可达8.22%,与模型预测值相对误差为0.13%。稳定性实验结果表明,核桃青皮萘醌类色素0⁷ d内具有良好的耐光、抗氧化还原和储藏性,80℃内热稳定性良好,Mg²⁺、Ca²⁺、Na⁺、K⁺对色素无明显作用,Al³⁺、Zn²⁺、Fe³⁺对该色素具有一定的增色作用,其中Fe3+作用最明显。超声波结合酶法提取工艺简单、高效、可行,提取的萘醌类色素具有较好的稳定性。      

Stability of haem pigments in model systems and cooked meat

The stability of sheep haemoglobin and myoglobin in aqueous solution at 80, 100 and 121°C for 1 h was measured by subjecting portions of the heated solutions to electrospray mass spectrometry (ESMS). ESMS dissociates haem proteins into the globin chains and the haem moiety and, with haemoglobin, degradation of the α-(15047·5 Da) and β-(16073·3 Da) chains was observed at all heating temperatures. Under the same conditions, sheep myoglobin dissociated into the globin (16923·2 Da) and haem parts but the globin was stable and few degradation products were observed in the ESMS trace (mass range 4-20 kDa) even after 1 h at 121°C. There did seem to be limited breakdown of the globin due to loss of 170 Da. From the amino acid sequence, it is postulated that this is due to loss of GLY-LEU from the N-terminus. Methods for extracting myoglobin from raw and cooked meat were then investigated. Water was adequate for myoglobin extraction from raw meat but urea solution was required for adequate extraction of cooked meat samples. Sheep meat was heated at 80, 100 and 121°C in sealed cans, extracted and the mass profile in the range 4-20 kDa measured. Myoglobin was the major peak when samples were heated for 10, 20, 30 and 40 min. After that time, other peaks appeared although the myoglobin globin chain was still apparent. The results are discussed in relation to using myoglobin as a marker for meat speciation.     

Isolation and identification of one kind of yellow pigments from model reaction systems related to garlic greening

It was established that green pigment(s) responsible for garlic greening is composed of yellow and blue species, and pyruvic acid (a product from 1-PeCSO or 2-PeCSO under the action of alliinase) reacted with pigment precursor (PP) model compounds, 2-(1H-pyrrolyl) carboxylic acids to produce yellow pigments. However, the structure of the yellow pigments is unknown. In present paper, we identified three yellow pigments (Y1, Y2 and Y3) from three reaction systems containing pyruvic acid and 2-(1H-pyrrolyl) acetic acid (P-Gly) or 1-(2′-methyl-1′-carboxy-propyl) pyrrole (P-Val) or 1-(2′-methyl-1′-carboxy-butyl) pyrrole (P-Ile), respectively, by LC-ESI MS/MS and IT-TOF mass spectrometry. The three pigments have a UV/visible maximum absorbance between 400 and 434 nm and might be formed by dimerisation of the three corresponding PP under participation of pyruvic acid, molecular formula of which are C₁₆H₁₆N₂O₄ (Y1), C₂₂H₂₈N₂O₄ (Y2) and C₂₄H₃₂N₂O₄ (Y3), respectively.     

Highly purified sugar concentrate from a residue of citrus pigments recovery process

Pigmented orange pulp wash (PW), a byproduct of citrus processing, was already studied to obtain anthocyanins and hydroxycinnamates using adsorption resins. The residue of such process was further investigated to obtain a purified sugar concentrate applying a series of resin adsorptions and membrane techniques. The final product and the intermediates were characterized by chemical and microbiological analyses. The results have shown that anthocyanins, limonoids, flavanones and hydroxycinnamates were absent in the starting material because totally removed by the treatment with the neutral polystyrene-divinylbenzene (PS-DVB) resin used to recover the pigments; the acidity was strongly reduced through a weakly basic ion-exchange matrix while the ultrafiltration (UF) process stabilized the product by removal of enzymes and microorganisms. Eighty percent of the water was eliminated by a reverse osmosis (RO) treatment, increasing the sugar concentration by four times. The final product (28 Brix) contained about 250 g/l of sugars (glucose, fructose and sucrose), 9 g/l of citric acid and 1 g/l of pectins. The concentrate, obtained from a residue that otherwise must be disposed, was a transparent liquid of slight amber color with a very low microbial count and could easily find application as a natural sweetener in food and beverage industries.     

Recycle of silicate waste into mesoporous materials

Template synthesis of porous carbon materials usually requires selective removal of template silica from the carbon/silica composites. It not only involves waste of valuable chemicals, but also poses significant environmental concerns including high waste treatment cost. Recycling of silicates released from such nanocasting methods is successfully performed for the first time to regenerate valuable mesoporous MCM and SBA type silica materials, which will not only help in saving valuable chemicals, but also in decreasing chemical waste, contributing in improvement of our environmental standards. This approach can thus improve cost effectiveness for the mass production of nanostructured carbon and others utilizing silica directed nanocasting method by recycling otherwise silicate waste into highly desirable valuable mesoporous silica.     

Product engineering of dispersed systems

Product engineering is the design of products with desired properties using the methods of process engineering. To reduce the number of process parameters, necessary to obtain the desired properties, a characteristic feature of the respective product is helpful. For a dispersed system this characteristic feature is its complex structure on a micro-scale. This micro-structure is the link between the process and the properties of the final product. The principles of product engineering of dispersed systems are explained and demonstrated by means of different examples: Though there are limits to this concept, certain properties of dispersed systems can be obtained by determining and applying property and process functions.     

Stability of hydroxycinnamic acids and caffeine from green coffee extracts after heating in food model systems

This study was designed to characterize the stability of hydroxycinnamic acids and caffeine obtained from green coffee beans in the form of lyophilized extract (GCE) during heating after supplementation to model systems with saccharose, potato starch, egg white protein, and sunflower oil. Also the addition of iron ions was used. Systems were prepared as a mixture of GCE with a single substance or in a more complex matrix. Heating was carried out at 180 °C for 0.5 and 1 h. Because of the saccharose content, some systems were heated only at 110 °C. The losses of hydroxycinnamic acids in heated systems ranged from 18 to 84 %, and the caffeine from 1.5 to 10 %. The presence of sunflower oil in the systems had the greatest influence on hydroxycinnamic acids degradation. However, in case of the system of each of the examined substances with the coffee preparation, an increased degradation of hydroxycinnamic acids resulting from the introduction of ferrous ions into the systems was observed. Earlier results concerning antioxidant activity of systems containing GCE allow to conclude that the degradation of hydroxycinnamic acids was weakly related to the decrease in antioxidant activity.     

Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization

A thermodynamic Gibbs energy minimization (GEM) solid solution-aqueous solution (SSAS) equilibrium model was used to determine the solubility of Zn from calcium silicate hydrate (CSH) phases doped with 0, 0.1, 1, 5, and 10% Zn at a unity (Ca+Zn)/Si molar ratio. Both the stoichiometry and standard molar Gibbs energy (G(o)298) of the Zn-bearing end-member in the ideal ternary Zn-bearing calcium silicate hydrate (CZSH) solid solution were determined by a "dual-thermodynamic" (GEM-DT) estimation technique. The SSAS model reproduces a complex sequence of reactions suggested to occur in a long-term weathering scenario of cementitious waste forms at subsurface repository conditions. The GEM model of CZSH leaching at several Zn loadings and solid/water (s/w) ratios in a C02-free system showed that, upon complete dissolution of portlandite and calcium zincate phases at decreasing s/w < 0.01 mol x kg(H2O)(-1), the total dissolved concentrations Si(aq), Ca(aq), and Zn(aq) are controlled by a CZSH solid solution of changing composition, with a trough-like Znaq drop by 2-3 orders of magnitude. Carbonation was simulated in another GEM model run series by CO2 titration of the system with initial s/w approximately 0.9 mol/kg(H2O). Formation of (Ca,Zn)-CO3 nonideal solid solution was predicted already at early reaction stage in the presence of both portlandite and calcium zincate hydrate phases. Upon their disappearance, pH, Zn(aq), C(aq), and fCO2 were predicted to change due to the incongruent dissolution of two concurrent CZSH-I and CZSH-II solid solutions, until the total re-partitioning of Ca and Zn into a carbonate solid solution coexisting with amorphous silica at fCO2 > 0.1 bar. Along this solid-phase transition, dissolved Zn(aq) concentrations follow a highly nonlinear trend. The model results predict that at low to moderate Zn loading (< or = 1% per mole Si), CZSH-type compounds can efficiently immobilize Zn in the near field of a cement-stabilized waste repository.     

3D woven green composites from textile waste: mechanical performance

Application of textile waste for development of value added green composites has been carried out in this work. Textile fabric waste is collected from various sources. These waste materials are garneted, so as to produce loose fibrous material, subsequently this fibrous material was converted into twisted strand for manufacturing of 3D woven preforms for production of composites. Twisted strands are converted into orthogonal 3D woven structure. The fibers extracted from waste material are combined with polypropylene in 60/40 proportion. Composites of various specifications are developed to examine their end-use applications. These composite materials are characterized for their mechanical behavior to find out the response against tensile loading, flexural stress, and impact force. The effects of moisture absorption on mechanical properties of composites are investigated. 3D woven fabric reinforced composites produced by using waste fiber yarn and normal cotton OE yarn do not exhibit any significant difference in the mechanical behavior of composite. This result confirmed that waste material can be safely used as reinforcing structure in green composite manufacturing.     

Aqueous solubility diagrams for cementitious waste stabilization systems. 3. Mechanism of zinc immobilizaton by calcium silicate hydrate

Zinc oxide was added during hydration of alite (C3S) as an analogue for solidification/stabilization by cement of metal-bearing hazardous waste. Curing of samples was stopped at various intervals between 8 h and 100 d, and the reaction products were analyzed by both X-ray diffraction (XRD) and X-ray absorption spectroscopy (EXAFS at Zn, Ca, and Si K-edges). Calcium zincate hydrate (CaZn2(OH)6 x 2H2O) initially formed together with calcium silicate hydrate (CSH) vanishes from X-ray diffractograms after 14 d, and no other crystalline Zn-bearing phase could be detected thereafter. EXAFS Zn K-edge data analysis reveals that Zn(O,OH)4 tetrahedra continue to determine the first shell coordination. However, a new Zn-Si bond appears in the second coordination shell as indicated by both Zn K-edge and Si K-edge EXAFS. Together with the Ca-Zn and Ca-Ca shells derived from the Ca K-edge EXAFS spectra, a structural model for the site occupation of Zn in CSH is proposed, whereby the Zn(O,OH)4 tetrahedra are bound in layer rather than interlayer positions substituting for the silicate bridging tetrahedra and/or at terminal silicate chain sites. This structural model enables ultimately the formulation of a thermodyamic Lippmann model to predict the aqueous solubility of Zn in solid solution with a CSH phase of a Ca/Si ratio fixed to unity.     

Effects of lipophillic pigments on colour of the green tea infusion

Studies about effect of pigments on colour of green tea infusion will help for quality evaluation and adopting suitable measure for prevention from non‐enzyme browning. HPLC results showed that concentrations of chlorophylls and pheophytin a in green tea infusions were higher than their thresholds, and that lutein and β‐carotene were near or above the thresholds. Significant correlation between pigments concentration and colour difference index in green tea infusion was also found. Therefore, lipophillic pigments did affect the colour of green tea infusion markedly, and the ratio of chlorophylls to pheophytins could be used as an indicator of infusion colour and quality of green tea.     

餐饮废油硅酸钠-活性白土精炼工艺优化

以餐饮废油为试验材料,对硅酸钠-活性白土精炼工艺进行研究。通过单因素试验和正交旋转回归组合设计优化后的精炼最佳工艺条件为:活性白土和硅酸钠总加量8%,反应温度80℃,反应时间30 min,活性白土与硅酸钠质量比值为4。在最佳条件下精炼率为79.6%,精炼油酸值(KOH)为0.71 mg/g,过氧化值为4.32 meq/kg,符合饲料用油的行业标准。     

Characteristics of wasteform composing of phosphate and silicate to immobilize radioactive waste salts

In the radioactive waste management, metal chloride wastes from a pyrochemical process is one of problematic wastes not directly applicable to a conventional solidification process. Different from a use of minerals or a specific phosphate glass for immobilizing radioactive waste salts, our research group applied an inorganic composite, SAP (SiO(2)-Al(2)O(3)-P(2)O(5)), to stabilize them by dechlorination. From this method, a unique wasteform composing of phosphate and silicate could be fabricated. This study described the characteristic of the wasteform on the morphology, chemical durability, and some physical properties. The wasteform has a unique "domain-matrix" structure which would be attributed to the incompatibility between silicate and phosphate glass. At higher amounts of chemical binder, "P-rich phase encapsulated by Si-rich phase" was a dominant morphology, but it was changed to be Si-rich phase encapsulated by P-rich phase at a lower amount of binder. The domain and subdomain size in the wasteform was about 0.5-2 μm and hundreds of nm, respectively. The chemical durability of wasteform was confirmed by various leaching test methods (PCT-A, ISO dynamic leaching test, and MCC-1). From the leaching tests, it was found that the P-rich phase had ten times lower leach-resistance than the Si-rich phase. The leach rates of Cs and Sr in the wasteform were about 10(-3)g/m(2)· day, and the leached fractions of them were about 0.04% and 0.06% at 357 days, respectively. Using this method, we could stabilize and solidify the waste salt to form a monolithic wasteform with good leach-resistance. Also, the decrease of waste volume by the dechlorination approach would be beneficial in the final disposal cost, compared with the present immobilization methods for waste salt.     

Recovery and characterization of proteins precipitated from surimi wash-water

The objectives of this study were testing the methodology involved in the recovery of water-soluble proteins from surimi wash-water (SWW) by shifting the pH and organic solvent use, and characterization of the recovered proteins. Water-soluble proteins were recovered from three successive washes in a surimi process; these were: 1.23 ± 0.08, 0.64 ± 0.06 and 0.54 ± 0.05 mg/mL for wash stages I (WS-I), II (WS-II) and III (WS-III), respectively. For WS-I, most of the recovered proteins had a molecular weight (MW) between 23.2 and 71.6 kDa with some traces having less than 23.2 kDa. WS-II and III also had MW between 23.2 and 71.6 kDa; however, at a lower amount. Maximum precipitation from surimi wash-water was obtained at pH 3.5 (66.3 g protein/100 ml SWW). Percentage of precipitation was directly related to temperature. Increasing the organic solvent concentration (10-60 g ethanol/100 g SWW) yielded greater precipitation. The highest precipitation (65.0 g protein/100 mL SWW) was obtained with ethanol concentration of 60 g/100 g SWW. Reaction time for pH shift and organic solvent had little or no significant effect (p > 0.05) on percentage of precipitation. Minimum solubility of recovered proteins occurred around pH 3.5 and 60 g/100 g of ethanol, an increase in temperature decreased protein solubility.     

欧李红色素在复杂体系中的抗氧化作用

用AAPH热分解生成的自由基引发脂质氧化,通过硫氰酸铁法和硫代巴比妥酸反应物法检测脂质的氧化进程,研究欧李红色素在用大豆磷脂脂质体模拟非均相生物体系和用非离子表面活性剂Tween 20稳定的葵花油水包油乳状液模拟非均相食品体系中的抗氧化活性,同时考查其与VC或VE的协同作用。结果表明:在大豆磷脂脂质体中0.001 6、0.004、0.008 mg/m L和在葵花油乳状液中0.02、0.05、0.10 mg/m L的欧李红色素均具有抗氧化活性,且其抗氧化能力随浓度的升高逐渐降低。考察欧李红色素与VC或VE的协同作用时发现,在大豆磷脂脂质体中0.001 6 mg/m L VC或VE以及在葵花油乳状液中0.02 mg/m L VC或VE的加入,均使复合抗氧化剂不显示协同增效作用。     

Bioactivities of low-grade green coffee and spent coffee in different in vitro model systems

Methanolic extracts of low-grade green coffee beans (LCB) and spent coffee were analysed for radical-scavenging activity (α,α-diphenyl-β-picrylhydrazyl radical) and oxygen radical absorbance capacity (ORAC). The extracts were also evaluated for anti-tumour (P388 cell assay), anti-inflammatory (J774A.1 cell assay) and anti-allergenic (RBL-2H3 cell line) activities in vitro. LCB extract was found to exhibit a radical-scavenging activity of 92.0% followed by spent Arabica (86.9%) and spent Robusta (82.0%) at a concentration of 50 ppm. The antioxidant activity of LCB extract, measured as Trolox equivalents (4416 μM/g) was significantly (p < 0.05) higher than that of the spent coffee extracts. However, extracts of spent coffee exhibited significantly (p < 0.05) more anti-tumour activity than the LCB extract in terms of cell viability. This could be due to the possible role of brown pigments (melanoidins and phenolic polymers), formed during roasting, which may protect cells from oxidative damage in the biological system. However, both the extracts of LCB and spent coffee showed limited anti-inflammatory and anti-allergic activities. The presence of phenolics and chlorogenic acids in appreciable quantities along with brown pigments makes these coffee by-products a source for natural antioxidants.     

Iron-binding ability of melanoidins from food and model systems

Soluble high molecular weight fractions isolated from the development of the Maillard reaction in 22 different model systems and food matrices were studied in order to assess their iron-chelating ability in vitro. Melanoidins and iron were incubated in a Na-acetate buffer (0.1 M, pH 5) at different weight ratios and free iron was measured by FAAS and the bathophenantroline procedure at the steady state. Melanoidins were classified at three levels according to their number of co-ordination sites for iron. Melanoidins from coffee (medium roasted), different types of beer (Pilsener, Abbeys, and dry-stout styles), and sweet wine (Pedro Ximenez) exerted a low iron-binding effect compared with melanoidins from model systems. The type of sugar was shown to be a significant parameter for obtaining melanoidins with high iron ability, and glucose was more efficient than lactose. No relationship was observed between browning and iron binding ability of melanoidins from model systems. The chromophoric residues were not the main co-ordination sites for iron complexation in the melanoidin structure.