Protein fibers

In general, protein fibers are fibers of moderate strength, resiliency, and elasticity. They have excellent moisture absorbency and transport characteristics. They do not build up static charge. While they have fair acid resistance, they are readily attacked by bases and oxidizing agents. They tend to yellow in sunlight due to oxidative attack. They are highly 

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Fibers (see Fibers, survey) used in textile production can have a wide variety of origins plants, ie, ceUulosic fibers (see Fibers, cellulose esters) animals, ie, protein fibers (see Wool) and, in the twentieth century, synthetic polymers. Depending on the part of the plant, the ceUulosic fibers can be classified as seed fibers, eg, cotton (qv), kapok bast fibers, eg, linen from flax, hemp, jute and leaf fibers, eg, agave. Protein fibers include wool and hair fibers from a large variety of mammals, eg, sheep, goats, camels, rabbits, etc, and the cocoon material of insect larvae (sUk). Real sUk is derived from the cocoon of the silkworm, Bombjx mori and for a long time was only produced in China, from which it was traded widely as a highly valuable material. 

There is Httle difference between the wet and the dry stress—strain diagrams of hydrophobic fibers, eg, nylon, acryHc, and polyester. Hydrophilic protein fibers and regenerated cellulose exhibit lower tensile moduH on wetting out, that is, the elongations increase and the strengths diminish. Hydrophilic natural ceUulosic fibers, ie, cotton, linen, and ramie, are stronger when wet than when dry. 

R. S. Asquith, ed.. Chemistry of Natural Protein Fibers, Plenum Press, New York and London, 1977 R. G. Stewart and L. E. Story, Wool Grease A Review of Its... 

Acid Dyes. These are anionic dyes, usually containing sulfonic acid groups, that are substantive to wool, other protein fibers, and polyamides when dyed from an acidic dyebath. The lower the pH the more rapid the dyeing, and exhaustion efficiency is enhanced by increased acidity. 

Mordant Dyes. This group includes many natural as well as synthetic dyes. They have no or low substantivity for textile fibers and are therefore appHed to ceUulosic or protein fibers that have been treated (mordanted) with metallic oxides to give points of attraction for the dye. The dye... 

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

Besides watet, the diet must provide metaboEc fuels (carbohydrate and fat) fot bodily growth and activity protein fot synthesis of tissue proteins fiber for roughage minerals for specific metabolic functions cettain polyunsamtated fatty acids of the n-3 and n-6 famihes fot eicosanoid synthesis and other functions and vitamins, otganic compounds needed in small amounts for many varied essential functions. 

Ribbon views of proteins with varying amounts of helices and pleated sheets. Immunoglobulin, an antibody, is made up almost entirely of pleated sheets (magenta). Myoglobin, which stores oxygen in muscle tissue, is composed of about 70% helix (blue). G-Actin, a component of muscle protein fibers, is a complex mixture of helices and pleated sheets. Regions with no specific secondaiy stmcture are shown in orange. 

Natural products have been noted for their potential health benefits from time immemorial and are the basis of Ayurveda, an ancient Indian medical practice (Bushkin and Bushkin, 2002). However, the potential benefits of several natural products reside in one or two active ingredients. For example green tea stands for polyphenols, soy for soy estrogens, broccoli for isothiocyanates and grape seed for polyphenols. The beauty of rice bran is that there are more than 100 antioxidants, several categories of bioactive phytonutrients, such as IP6, polyphenols, phytosterols, tocotrienols, y-oryzanol, B vitamins, minerals and trace minerals in addition to fat, protein, fiber, polysaccharides and other nutrients. These phytonutrients and antioxidants of rice bran are believed to act at the cellular level, and their synergestic function is responsible for the positive health benefits. 

Skin is unstable to varying environmental conditions and deteriorates readily under humid conditions or through biological activity, or both. Basically, the decay of much ancient skin and hide results from hydrolysis, that is, the reaction of the protein fibers in the skin with water in extreme cases, the hydrolysis of skin and hide may cause their total dissolution, and quite often, under humid and hot environmental conditions, nothing remains to indicate that skin or hide was once there. 

Asquith, L. (1977), Chemistry of Natural Protein Fibers, Plenum, New York. 

Blood coagulation. The third major step in hemostasis is coagulation, or the formation of a blood clot. This complex process involves a series of reactions that result in formation of a protein fiber meshwork that stabilizes the platelet plug. Three essential steps lead to clotting (see Figure 16.1) ... 

Solubilized vat Cotton, wool, cellulose, and protein fibers silk Impregnated fiber when treated with an oxidized agent usually sulfuric acid and sodium nitrite for cotton dichromate wool and silk therefore, no alkali is involved. This class is applicable to cellulose and protein fibers Dyeing, printing and wool in fast shades... 

Reactive dyes contain substituent that, when activated, react with the -OH groups of cellulose (i.e., cotton) or with -NH2 and -SH groups of protein fibers (i.e., wool) forming covalent bonds, making them among the most permanent of dyes. 

Because of thick intertwining protein fibers in the cell and in the area of the cell membrane, cell structure is rigid and remains so, but is altered by the osmotic effect of the penetrating water. The uptake of water entails a continual shifting of the cell... 

When structured soy protein fiber was added to fermented salami at 15 or 30% levels, trained sensory panels found the flavor to be undesirable, whereas a 116-member untrained panel found the product containing 30% soy flour to be undesirable in flavor, tenderness and overall desirability (26). The flavor of beef patties containing 20% soy protein flour or concentrate was rated about equal to all beef patties by a 52-member panel, whereas patties containing 30% were scored lower by the panel (6). Berry et al. (7) found the characteristic "soy-like" flavor to be more... 

Neuroanatomical and neuropathological basis of Alzheimer s disease Histological features of Alzheimer s disease include neuritic plaques and neurofibrillary tangles (Boiler and Duyckaerts 1997). Neuritic plaques are composed of extracellular deposits of j8-amyloid protein and apolipoprotein E and are found primarily in neocortex. j8-amyloid is derived from an amyloid precursor protein, and is suspected to be a chief causal factor in Alzheimer s disease pathology (Samuel et al. 1997). Neurofibrillary tangles are clusters of protein fibers found in the cell body and composed of tau protein, which normally serves as a cytoskeletal element. Neurofibrillary tangles progress from entorhinal cortex to hippocampus, and then to neocortical areas. 

The cytoplasm of eukaryotic cells is traversed by three-dimensional scaffolding structures consisting of filaments (long protein fibers), which together form the cytoskeleton. These filaments are divided into three groups, based on their diameters microfilaments (6-8 nm), intermediate filaments (ca. 10 nm), and microtubules (ca. 25 nm). All of these filaments are polymers assembled from protein components. 

Silk is a protein fiber that is woven into fiber from which textiles are made including clothing and high-end rugs. It is obtained from the cocoon of silkworm larvae. While most silk is harvested from commercially grown silkworms, some is still obtained from less well-established sources. 

Most plant and animal materials contain natural fibers that have been concerted into useful fibers for thousands of years including ropes, building materials, brushes, textiles, and brushes (Table 18.6). Animal protein fibers such as wool and silk are no longer competitive with synthetic fibers with respect to cost but are still often utilized in the production of high-end rugs. Some of these rugs are hundreds of years old yet retaining their color and physical properties. 

Vicara Protein fiber Virginia-Caroline Chemical... 

Papapostolou D, Smith AM, Atkins EDT, Oliver SJ, Ryadnov MG, SerpeU LC, Woolfson DN. Engineering nanoscale order into a designed protein fiber. Proc Natl Acad Sci USA 2007 104 10853-10858. 

Ryadnov MG, Woolfson DN. Engineering the morphology of a self-assembling protein fiber. Nat Mater 2003a 2 329-332. 

Smith AM, Acquah SEA, Bone N, Kroto HW, Ryadnov MG, Stevens MSP, Walton DRM, Woolfson DN. Polar assembly in a designed protein fiber. Angew Chem Int Ed 2005 44 325-328. 

Smith AM, BanweU EE, Edwards WR, Pandya MJ, Woolfson DN. Engineering increased stability into self-assembled protein fibers. Adv Funct Mater 2006 16 1022-1030. 

C. Note that protein fiber formation is temperature dependent. A continuous fibrous matrix forms at about 130°C. 

Figure 13. SEM of Bacos spun soybean protein fiber simulated meat product. Egg albumin used as adhesive for fibers (33).

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