Color fixation

To verify the part played by yeasts in color fixation (48), we prepared a synthetic alcoholic mixture (10% alcohol, 5 grams/liter tartaric acid adjusted to a pH of 3.0 with concentrated sodium hydroxide) and added a solution of macerated Cabernet Sauvignon skins. We studied the... 

Color Fixation. Oxidation of cmde fats and oils can also lead to color fixation. The most notable examples of color fixation are in cottonseed (25) and pahn oils, where oxidation of gossypol and carotenoid pigments are involved. 

However, if the oil is not properly pretreated (too high residual phosphatides, iron, other impurities ) or if traces of bleaching earth are still present, the oil can become darker during deodorization. This phenomenon is also known as color fixation because it is almost impossible to remove these color pigments once they are formed. 

For nearly 30 years (327,475,478) it has been known that color fixation, flavor, and odor were greatly improved when ascorbic acid was included in the formulation of cooked, nitrited, ground pork products and that frankfurters containing ascorbate had a more desirable and... 

Nitrates and nitrites are spread within environmental, food, industrial, and physiological systems. Nitrate may be reduced by bacteria to nitrite, and nitrite produces carcinogenic nitrosamines. Nitrite is also commonly employed in cured meat products to provide antimicrobial action, color fixation, and preservation. Nitrite can oxidize hemoglobin iron(II) to iron(III) resulting in methemoglobin, leading to a condition known as methemoglobinemia in children mainly. In excess, nitrates and nitrites may be toxic. 

Molybdate orange and red are pigments (qv) that contain lead(II) molybdate [10190-33-3], PbMoO, formulated in mixed phases with PbCrO and PbSO. The mixed phase is more intensely colored than any of the component phases. Concerns about lead content are lessening the use of these materials (see also Paint). Various organic dyes are precipitated with heteropolymolybdates. This process allows the fixation of the dye in various fabrics. The molybdenum anion generally imparts light stabiHty to the colorant as weU (91). 

Filter paper impregnated with dicarbonyl(benz-2,l,3-thiadiazole)rhodium chloride gives characteristic colorations with the aminophenol isomers after fixation and can be used as an indicator paper (99). 

In the name Procion Red H-E 7B, Procion is the Zeneca trade name for its range of reactive dyes for cotton. Red denotes the main color of the dye. H-E denotes the dye to be hot dyeing and an exhaust dye (high fixation), and 7B denotes it to be a very bluish red dye, ie, a magenta. 

The process of textile print coloration can be divided into three steps. First, the colorant is appHed as pigment dispersion, dye dispersion, or dye solution from a vehicle caUed print paste or printing ink, containing in addition to the colorant such solutions or dispersions of chemicals as may be required by the colorant or textile substrate to improve and assist in dye solubUity, dispersion stabUity, pH, lubricity, hygroscopicity, rate of dye fixation to the substrate, and colorant-fiber bonding. The required viscosity characteristics of a print paste are achieved by addition of natural or synthetic thickening agents or by use of emulsions. 

Dye fixation on acryUc fibers and acetate can be done by atmospheric steaming at 100—102°C for 20—30 min. With modified polyester only pressure steam produces flUl fixation and color yield. Afterscouting is by rinsing and detergent scour. A scouting auxUiary with affinity to the fibers can be used to prevent redeposition of tinsed out dye. 

Phthalocyanine Dyes. These days are synthesized as the metal complex on the textile fiber from, eg, phthalonittile and metal salts. A print paste typicaUy contains phthalonittile dissolved in a suitable solvent and nickel or copper salts. During a heat or steam fixation of 3—5 min, the dye is formed. The color range is restricted to blue and green shades and can be influenced to some extent by the choice of metal salt. A hot acid bath during afterscouting completes the process. 

Resist Printing. In resist printing, print pastes are used that can inhibit the development or fixation of different dyes that are apphed to the textile prior to or after printing. These resists can be of a chemical or mechanical nature, or combine both methods. For example, fiber-reactive dyes, which require alkaU for their fixation, can be made resistant by printing a nonvolatile organic acid, such as tartaric acid, on the textile. Colored resists are obtained by printing pigments with a nonvolatile acid. 

Reactive groups have minimal auxochrome effect on color intensity, and color yield per molecular weight decreases with increasing numbers of reactive groups. Increased dye fixation and reduced environmental impact of hydrolyzed dye more than compensate for color reduction of additional reactive groups. 

Kompensationsfarbe, /. complementary color. kompensieren, v.t. compensate, komplementar, a. complementary. Komplementarfarbe, /, complementary color. Komplement-bindung, -fixierung, /. complement fixation, -winkel, m. complementary angle. 

Fig. 12. The nitrogen fixation genes of Azotobacter vinelandii. This orgEinism has three nitrogenase systems, viz nif, vnf, and anf, which it uses for fixing N2 under different environmental conditions. The boxes with slanted hatching indicate the structural genes of the three systems, those colored dark gray are required for eiU three systems, and those with vertical hatching are required for both the vnf and anf systems.

Black-and-white photography, fixation in, 19 213 Blackbody color of, 7 327 emittance from, 19 131-132 spectral radiance of, 24 453 Blackbody radiation law, 24 452 Blackbody responsivity, 19 132 Blackbody temperature sensor, 11 149-150 Black-box approach, to reliability modeling, 26 987-988, 990 Black copper, 16 144 Black crappie, common and scientific names, 3 187t... 

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