Starch

Abstract

STARCH ], (C 6 H 10 O 5 ) n , the main reserve food of plants, constitutes two-thirds of the carbohydrate caloric intake of most humans but only 47% of the carbohydrate caloric intake by Americans, who also get about 52% of their carbohydrate calories from sugar. Commercial starches are obtained from seeds, particularly corn, waxy corn, high amylose corn, wheat, and rice, and from tubers or roots particularly potato, sweet potato, and tapioca (cassava). Their principal use is in foods; the major nonfood uses are in sizing of paper and textiles, and as adhesives (qv).Egyptian papyrus bonded with a starchy adhesive has been dated to 3500-4000 BC. Pliny the Elder (23-74 AD) described Egyptian use of wheat starch modified by boiling in vinegar to produce a smooth surface for papyrus documents.Enzyme technology, especially immobilized-enzyme technology, has allowed production of sweeteners (qv) from corn starch, ie, corn syrup or high fructose corn syrup (HFCS), and often also provides sources of chemical feedstocks to replace petroleum. Enzymes, notably α-amylase, glucoamylase, and glucose isomerase, catalyze specific polysaccharide-degrading reactions to produce various glucose syrups. Immobilized enzyme technology has significant advantages because of the recoverability of the enzymes and their re-use in a continuous system, rather than in batch systems. Starch conversion technology, especially conversion to glucose and fructose-containing syrups, has been reviewed (1) (see Enzyme applications; Syrups).The quasi-crystalline structure of natural starch granules causes them to be insoluble in water at normal room temperature and gives them relative resistance to carbohydrases other than α-amylase and glucoamylase unless the granules become swollen. Three-dimensional arrangements of crystalline and amorphous zones in starch granules have been suggested (2).

Protein–Polysaccharide Composite Materials: Fabrication and Applications

“…Starch is an abundant polysaccharide that is found in the roots, seeds, and stems of various plants and crops [65]. Starch is constructed of anhydroglucose units and subsequently comprises two different polymers: Amylose and amylopectin.…”

The impact of heat-moisture treatment on the molecular structure and physicochemical properties of normal and waxy potato starches

“…The granules become increasingly susceptible to sheardisintegration as they swell and release soluble material as they disintegrate (Whistler and BeMiller, 1997). The paste that is obtained on gelatinization is a viscous mass consisting ofa continuous phase (a molecular dispersion) of solubilized amylose and/or amylopectin and a discontinuous phase of granule remnants (granule ghosts and fragments) (Whistler and BeMiller, 1997 , 1997,Evansand Haisman, 1979Hagenimana and Ding, 2005;Hoover and Vasanthan, 1994b;Jane el al.,1999;Jayakody el al.,2007;Ziegler el al., 1993). The pasting profile of starch is commonly monitored using a Rapid ViSCO™ Analyser (RVA), which is a heating and cooling viscometer configured especially for testing starch-based and other products requiring precise control of temperature and shear (Hagenimanaand Ding, 2005).…”

Assessment of the Extent of Starch Dissolution in Dimethyl Sulfoxide by 1H NMR Spectroscopy

“…Starch is a major component of human diets, supplying more than 50% of caloric energy, and is a major component of a large number of food plants, for example wheat, potatoes, maize, rice, peas, and bananas 1, 2. Furthermore, being renewable, cheap, and biodegradable, starch has major applications in the paper, pharmaceutical, and textile industry 2–5.…”

“…Starch has two components: the overall smaller molecules of amylose exhibit a low level of long‐chain branching, while the larger amylopectin molecules have a high level of short‐chain branching 6. Depending on the natural source of the starch, the amylose content can vary from 0 to 85% 1. Many investigations on starch have been made after dissolution or dispersion in aqueous media: in alkaline conditions,20–23 with treatment at high temperature and pressure,23–27 under microwave irradiation,9, 15, 24, 28, 29 with sonication,24 or under stirring 25.…”