Starch state

In many foods, both starch and protein can be encountered so that understanding interactions between them would be useful. The selectivity in interaction between proteins and starches is best seen in results of dynamic rheological studies. The results depend upon the molecular structure of protein, the starch state of the granules and the amylose/amylopectin ratio, the composition of protein and starch, as well as the phase transition temperatures are important factors influencing protein-starch interaction. Because proteins and starches are thermodynamically different polymers, their presence together may lead to phase separation, inversion, or mutual interaction with significant consequences on texture (Morris, 1990). 

Konjac flour, derived from the konjac plant tuber, has a long history of use in the Ear East, but is a newcomer to the United States. It reacts with many starches to enhance the viscosity of both, and is used in gels that are stable in boiling water. 

Eastman Goal Chemicals. In 1983 Eastman Chemical Co. became the first chemical producer in the United States to return to coal as a raw material for large-scale manufacture of industrial chemicals (35). In that year, Eastman started manufacturing acetic anhydride from coal. Acetic anhydride is a key intermediate for production of coatings, ceUulosic plastics, and cellulose acetate fibers. Acetic anhydride from other sources also is used in the manufacture of pharmaceuticals, starches and sweeteners, and flavors and fragrances. 

Starches, used first in the late 1930s for filtration control (71), are stiU in use in the 1990s. Com starch is most commonly used in the United States. Potato starch is also used in the United States but primarily in Europe and elsewhere. Both com and potato starches are pregelatinized before dispersion in water (72). The API specifications for drilling fluid starch are listed in Table 8 (73). 

Specific optical rotation values, [a], for starch pastes range from 180 to 220° (5), but for pure amylose and amylopectin fractions [a] is 200°. The stmcture of amylose has been estabUshed by use of x-ray diffraction and infrared spectroscopy (23). The latter analysis shows that the proposed stmcture (23) is consistent with the proposed ground-state conformation of the monomer D-glucopyranosyl units. Intramolecular bonding in amylose has also been investigated with nuclear magnetic resonance (nmr) spectroscopy (24). 

Commercial starch is mainly com starch, but smaller amounts of sorghum, wheat, and potato starch are also produced. In 1992, 1303 million bushels (45.8 X 10 m ) of com were ground for starch and other products (120) 1 m com weighs - 721 kg and yields 438 kg starch, 26 kg oil, and 142 kg combined gluten and hulls. In the United States in 1994—1995, 462 million bushels were used to produce high fmctose com symp, 231 million bushels went to produce D-glucose, 533 million bushels were used for alcohol production, and 247 million bushels were converted to starch (121). 

Liquid sucrose and Hquid invert, generally made by redissolving white sugar and inverting with invertase enzyme, are refinery products in Europe and outside the United States. In the United States they have been almost completely replaced by cheaper com symps made by enzymatic hydrolysis of starch and isomerization of glucose. 

Nonabsorbable Natural Sutures. Cotton and silk are the only nonabsorbable sutures made from natural fibers that are stiH available ia the United States. Cotton suture is made from fibers harvested from various species of plants belonging to the genus Gossipium. The fiber is composed principally of ceUulose. The seeds are separated from the cotton boUs, which are carded, combed, and spun iato yams that are then braided or twisted to form sutures ia a range of sizes (Table 4). The suture is bleached with hydrogen peroxide and subsequendy coated (finished or glaced) with starch and wax. The suture may be white or dyed blue with D C Blue No. 9. 

Dextrose (D-glucose) is by far the most abundant sugar in nature. It occurs either in the monosaccharide form (free state) or in a polymeric form of anhydrodextrose units. As a monosaccharide, dextrose is present in substantial quantities in honey, fmits, and berries. As a polymer, dextrose occurs in starch, cellulose (qv), and glycogen. Sucrose is a disaccharide of dextrose and fmctose. 

Com symps [8029-43 ] (glucose symp, starch symp) are concentrated solutions of partially hydrolyzed starch containing dextrose, maltose, and higher molecular weight saccharides. In the United States, com symps are produced from com starch by acid and enzyme processes. Other starch sources such as wheat, rice, potato, and tapioca are used elsewhere depending on avadabiHty. Symps are generally sold in the form of viscous Hquid products and vary in physical properties, eg, viscosity, humectancy, hygroscopicity, sweetness, and fermentabiHty. 

Enzymes are specific, however. For example, starch is depolymerized using enzymes to D-glucose (dextrose). The solution of glucose is then treated with glucose isomerase [9055-00-9] to give D-fmctose in about 42% yield. No D-mannose is formed. Addition of isolated D-fmctose to this solution gives the common 55% high fmctose com symp (HFCS) so widely used in soft drinks in the United States. HFCS is about 1.5 times as sweet as sucrose. 

Industrial ethyl alcohol can be produced synthetically from ethylene [74-85-17, as a by-product of certain industrial operations, or by the fermentation of sugar, starch, or cellulose. The synthetic route suppHes most of the industrial market in the United States. The first synthesis of ethanol from ethylene occurred in 1828 in Michael Faraday s lab in Cambridge (40). 

Starches. In the United States, all potable alcohol, most fermentation industrial alcohol, and most fuel alcohol is currendy made principally from grains com is the principal feedstock for fuel alcohol. Fermentation of starch from grain is somewhat more complex than fermentation of sugars because starch must first be converted to sugar and then to ethanol. This process was known to the ancient Egyptians and Mesopotamians who brewed beer almost 5000 years ago (202). The simplified equations for the conversion of starch to ethanol are... 

Coagulation involves the addition of chemicals to alter the physical state of dissolved and suspended solids. This facilitates their removal by sedimentation and filtration. The most common primary coagulants are alum ferric sulfate and ferric chloride. Additional chemicals that may be added to enhance coagulation include activate silica, a complex silicate made from sodium silicate, and charged organic molecules called polyelectrolytes, which include large-molecular-weight polyacrylamides, dimethyl-diallylammonium chloride, polyamines, and starch. 

Standard pressure, 54 Standard state, 210 Standard temperature, 54 Starch, 425 iodine test, 358 structure, 431 Stars, 447... 

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