Functionalization starch

Functionally, starch can be considered as a polysaccharide synthesized in a manner permitting its efficient degradation. Hence, biosynthesis of the starch granule is a delicate balance between efficient packing of the glucan chains and the possibility of breaking these structures at degradation. To complete this enzymatically catalyzed process in the potato tuber, a multitude of different enzyme activities are required. 

CNC is derived as nanowhiskers for use as reinforcement in biopolymers such as starch, PLA, and PHB. Apart from being biodegradable, these nano whiskers have high specific strength and stiffness. Similarly, chitin nanowhiskers are synthesized from chitin, the second most abundant biopolymer after cellulose. These nanowhiskers have many desirable properties for use as reinforcements, like low density, nontoxicity, biodegradability, biocompatibility, easy surface modification, and functionalization. Starch nanoparticles (SNP) are synthesized from starch granules for use as reinforcement. 

Native starches, obtained by the various wet-milling processes described in Chapter 8, are industrially transformed by physicochemical and enzymatic processes into modified or functional starches or an array of syrups with different degrees of sweetness. Approximately 285 million bushels of native and modified starches were produced in the United States in the year 2006 (U.S. Department of Agriculture, Economic Research Service 2009). Modified starches acquire specific functional properties for special applications in the food industry. They are widely used as thickeners in the canning industry, as base for batters and breadings (Chapter 10), as emulsifiers, and as adhesives or glues in non-food-related industries. 

Starch-based foams can be prepared from different starch sources, with 70% of the polystyrene being replaceable with biopolymer starch. Functional starch-based plastic foams can be prepared from different starch sources, depending on their availability. 

Diastase or amylase is formed when malt is produced by the germination of barley grains. Malt is therefore a good source of the enzyme. Diastase is also secreted by the salivary glands (when it is known as ptyalin), and also by the pancreas. Its function is to hydrolysef starch to a mixture of maltose and dextrin ... 

Standards for dmg chemicals are pubUshed ia USP—NE. Dmg substances are chemicals that have therapeutic or diagnostic uses, whereas pharmaceutical iagredients provide preservative action, fiavoiing, or hilfillment of a function ia the formulation of dosage-form dmgs. Examples of dmg substances are acetaminophen [103-90-2] ampicillin [69-53-4] aspirin [50-78-2] powdered ipecac, riboflavin [83-88-5] staimous fluoride [7783-47-3] and thyroid. Examples of pharmaceutical iagredients are ethylparaben [120-47-8] lactose [63-42-3] magnesium stearate [557-04-0] sodium hydroxide [1310-73-2] starch [9005-25-8] and vanillin [121-33-5],... 

The lambda type is nongelling, and functions as a thickner. Iota-carrageenan has been recommended (45) for use in formulating low fat ground beef due to its abihty to retain moisture, especially through a freeze—thaw cycle which is typical for ground beef patties. Oat bran and oat fiber can also be used to improve moisture retention and mouth feel. Modified starches can be used as binders to maintain juiciness and tenderness in low fat meat products. Maltodextrins (dextrose equivalent less than 20) may be used as binders up to 3.5% in finished meat products. Other carbohydrates such as konjac flour, alginate, microcrystalline cellulose, methylceUulose, and carboxymethylceUulose have also been used in low fat meat products (see CELLULOSE ETHERs). 

Functional Blends. The term functional blend refers to various ingredient blends formulated to achieve a certain objective such as fat reduction. An example of this blend consists of water, partially hydrogenated canola oil, hydrolyzed beef plasma, tapioca flour, sodium alginate, and salt. This blend is designed to replace animal fat and is typically used at less than 25% of the finished product. Another functional blend is composed of modified food starch, rice flour, salt, emulsifier, and flavor. A recommended formula is 90% meat (with 10% fat), 7% added water, and 3% seasoning blend... 

Millet Jelly Production. Starch powder is heated together with oxahc acid and hydrolyzed to produce millet jelly. Oxahc acid functions as a hydrolysis catalyst, and is removed from the product as calcium oxalate. This apphcation is carried out in Japan. 

Potassium is required for enzyme activity in a few special cases, the most widely studied example of which is the enzyme pymvate kinase. In plants it is required for protein and starch synthesis. Potassium is also involved in water and nutrient transport within and into the plant, and has a role in photosynthesis. Although sodium and potassium are similar in their inorganic chemical behavior, these ions are different in their physiological activities. In fact, their functions are often mutually antagonistic. For example, increases both the respiration rate in muscle tissue and the rate of protein synthesis, whereas inhibits both processes (42). 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

A recent trend in the baking industry is to produce bakery foods with either no or reduced fat, to achieve perceived nutritional benefits (25). The functions of fat are achieved, to a degree, with materials such as maltodextrins and modified starches in combination with gums and emulsifiers (see Fat replacers). 

The stmcturaUy similar starch amylose polymer is linked through the a anomeric configuration. The three hydroxyl functions pet anhydroglucose unit ate noteworthy these hydroxyls ate the active sites for ether formation. 

A slurry of the starch is cooked in the presence of a heat-stable bacterial endo-a-amylase. The enzyme hydrolyzes the a-l,4-glycosidic bonds in pregelatinized starch, the viscosity of the gel rapidly decreases, and maltodextrins are produced. The process may be terrninated at this point. The solution is purified and dried, and the maltodextrins are utilized as blandtasting functional ingredients in dry soup mixes, infant foods, sauces and gravy mixes, etc. 

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