Oxidative Discolorations

Both pigments combine reversibly with oxygen, carbon monoxide, and nitric oxide to form bright red oxyhemo (or myo) globin, carbon monoxide hemo (or myo) globin, and nitric oxide hemo (or myo) globin, respectively. In all of these compounds the iron remains in the ferrous 

Two types of oxidative changes are chiefly responsible for the abnormal brown, grey, and green discoloration of meat. One involves the oxidation of the ferrous iron in the heme compound to the ferric condition the second is a direct attack by oxygen on the porphyrin ring.  

The general chemistry of the meat-curing process is well covered by Urbain (1951) and the part played by bacteria in this process by Jensen (1945). Jensen (1949) has also described the curing process and various types of cured meat products in nontechnical language. 

Total Brightness (Average) of Bacon Samples at Conclusion of Heat Treatment Duration of 

The mechanism by which protein denaturing agents are able to effect reduction of the ferric iron in the presence of nitrite (or nitric oxide) is obscure. It is probable that an intermediate is involved. Keilin and Hartree (1937) demonstrated that nitric oxide combined not only with 

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A number of techniques are available for determining the composition of a solid surface. Since the surface plays an important role in many processes, such as oxidation, discoloration, wear, and adhesion, these techniques have gained importance. The choice of a surface analysis technique depends upon such important considerations as sampling depth, surface information, analysis environment, and sample suitability. Different... 

MMBS is much less accessible to oxygen than as a powder so that mild oxidative discoloration can be conveniently monitored at 170°C in a time frame of maximum 5 h. A sample of milled sheet is positioned between two Mylar films and pressed. Then the films are removed, and the plaque is cut into rectangles, which are placed in a forced air oven. Samples are periodically removed and rated for their color development. 

Yachigo, S. Ida, K. Saski, M. Inoue, K. Tanaka, S. Studies on polymer stabilizers. Part V. Influences of structural factors on oxidative discoloration and thermal stability of polymers. Polym. Deg. Stab. 1993, 39, 317-328. 

During photo-oxidation discoloration as well as a decrease of the mechanical properties can be observed, which of these two is most important highly depends on the thickness of the article and its application. To increase the stability of PA66 UVAs as well as HALS can be applied (Fig. 17.11). In the case of PA 6 and 12 the light... 

Leffler EB, Spencer HM and Burger A, Dissociation constants of adrenergic amines JACS, 73,2611-2613 (1951). NB See Amphetamine for details. Decomposes in aqueous solution. Result claimed to be accurate to 0.02 log unit, but recognised (oxidative) discoloration of solution even when pH was measured as rapidly as possible. 

Features Highly functional yields coatings with exc. resist, to abrasion, hydrolysis, oxidative discoloration, impact, soivs., and staining low VOC Properties Translucent disp. colloidal particle size sp.gr. 1.05 dens. 8.76 Ib/gal vise. < 100 cps TCC flash pt. (PMCC) > 100 C pH 7-9 surf, tens. 51 dynes/cm VOC 347.3 g/l Film props. tens. str. 7000 psi tens, elong. 150% (ultimate) anionic 30% solids Witcobond W-234 [UniroyaQ... 

B8.4 The shielding gas flow should be maintained until the electrode has cooled. When the electrodes are properly cooled, the arc end will appear bright and polished. When improperly cooled, the end may oxidize and appear to have a colored film which can, unless removed, adversely affect the weld quality on subsequent welds. All connections, both gas and water, should be checked for tightness. Oxidized, discolored, or otherwise contaminated electrodes wiU cause difficult arc starting and may prevent starting depending upon conditions and the arc starting method used. 

The fresh, sweet must can be treated with sulfur dioxide (50 mg SO2/I) to suppress oxidative discoloration and the growth of undesirable microorganisms. In order to remove undesirable odors or off-tastes, the must is treated with activated charcoal and, when necessary, is clarified by separators or filters. In general, sulfurization before fermentation is dispensed with if the material is faultless and pure culture yeast is used. If required, the must is pasteurized by a short heat treatment (87 °C/2 min). 

Influence of recycling on aging properties (120 °C) of polypropylene as a function of quality of the recycled material recycled material = polypropylene aged in a convection oven (new material) recycled material w/o optical changes recycled material, oxidized discolorations recycled material, strongly oxidized = polypropylene pest... 

The kinetic curve of the photo-oxidation discoloration of ABS is in two stages [1114] ... 

The breakdown of protective coating systems on structures often leads to this form of corrosion. Dulling of a bright or poUshed surface, etching by acid cleaners, or oxidation (discoloration) of steel are examples of surface corrosion. Corrosion-resistant alloys and stainless steels can become tarnished or oxidized in corrosive environments. Surface corrosion can indicate a breakdown in the protective coating system, however, and should be examined closely for more advanced attack. If surface corrosion is permitted to continue, the surface may become rough and surface corrosion can lead to more serious types of corrosion. 

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