Sources, of starches

Starch is obtained from a variety of plant sources. Corn, cassava, sweet potato, wheat, and potato are the major sources of food starch while sorghum, barley, rice, sago, arrowroot, etc. serve as minor sources of starch in different localized regions of the world (Gaillard, 1987 Ratnayake and Jackson, 2003). Raw starch granules do not disperse in cold water. This limits the use of raw native starches for food as well as industrial applications, and therefore starch is often cooked during product-manufacturing... 

Starch is one of the most abimdant plant polysaccharides and is a major source of carbohydrates and energy in the human diet (Zobel and Stephen, 1995). Starch is the most widely used hydrocolloid in the food industry (Wanous, 2004), and is also a widely used industrial substrate polymer. Total annual world production of starch is approximately 60 million MT and it is predicted to increase by additional approximately 10 million MT by 2010 (FAO, 2006b LMC International, 2002 S. K. Patil and Associates, 2007). Com/maize Zea mays L.), cassava (also known as tapioca—Manihot escu-lenta Crantn.), sweet potato Ipomoea batatas L.), wheat Triticum aestivum L.), and potato Solanum tuberosum L.) are the major sources of starch, while rice Oryza sativa L.), barley Hordeum vulgare L.), sago Cycas spp.), arrowroot Tacca leontopetaloides (L.) Kimtze), buckwheat Fagopyrum esculentum Moench), etc. contribute in lesser amounts to total global production. 

The production of CDs via enzymatic reaction with starch has been recently reviewed (i 7). CGTase is an extracellular protein and is usually isolated as a crude mixture from the medium. This crude protein is used directly for industrial fermentations. The basic process involves standard enz3miatic fermentation, with careful attention to reaction temperature. All three CDs and some Unear oligosaccharides are normally produced. Yields are highly dependent on the source of starch substrate. Potato starch is normally used or an extract of potato starch is often added to other starches 18-19), The potato starch component(s) responsible for stimulating CD formation have not been determined. Low starch concentrations (5%-10%) are normally used industrially. Published yields are in the 50% - 80% conversion range. 

These are accomplished in large fermenters in chemical plants, mostly in the Midwest. The cheapest feedstock is starch rather than sugar (other enzymes convert starch to glucose), and com from the Midwest is the cheapest source of starch. 

While potato tuber is an important source of starch, it also contains 30-35 g buffer-extractable protein per kg dry weight (Pots et al., 1999). Protein yield per hectare of potatoes has been estimated as 500-1000 kg. The aqueous solution remaining after industrial potato starch manufacture, i.e., the potato fruit juice, contains approximately 1.5% (w/v) of soluble protein, mainly... 

Glucose syrups, also known as com syrups in the United States, are defined by the European Commission (EC) as a refined, concentrated aqueous solution of D(+)-glucose, maltose and other polymers of D-glucose obtained by the controlled partial hydrolysis of starch (Howling, 1984). Glucose syrups were fust manufactured industrially in the nineteenth century by acid hydrolysis of starch. Hydrochloric acid was normally used, because sulphuric acid caused haze in syrups due to insoluble sulphates. The source of starch can vary in the United States corn is widely used, whereas in other parts of the world wheat, potato and cassava starch are also employed. Acid hydrolysis of starch is still used today. The method is non-specific, but if conditions are tightly controlled, it is possible to make products with a reasonably consistent carbohydrate profile. 

A good source of starch, B-complex vitamins, iron, potassium, zinc, and other essential minerals... 

Outside of the use of cellulose for papermaking, starch is the most widely used plant-derived carbohydrate for non-food uses. Around 60 million tonnes of raw starch are produced per year for food and non-food uses. The US accounts for most of the world s production, utilising starch from maize, which accounts for over 80% of world production. The starch market in the US is driven by the large isoglucose sweetener market and now increasingly by the growing bioethanol market, which uses maize as a fermentation feedstock. Europe derives most of its starch from wheat and potatoes, which account for 8% and 5% of world starch production, respectively. The other main source of starch is cassava (tapioca), produced in South East Asia. Small amounts of oat, barley and rice are also exploited for starch production. Many edible beans are also rich in starches, but are not commonly exploited for non-food uses. 

In the eighteenth century, more economical sources of starch than wheat were being sought. In 1732, the Sieur de Guife recommended to the French government that potatoes be used to manufacture starch. The potato starch industry in Germany dates from 1765 (see Chapter 11). 

In nature, the availability of starch is just second to cellulose. The most important industrial sources of starch are corn, wheat, potato, tapioca and rice. In the last decade, there has been a significant reduction in the price of corn and potato starch, both in Europe and the USA. The lower price and greater availability of starch associated with its very favourable environmental profile aroused a renewed interest in development of starch-based polymers as an alternative to polymers based on petrochemicals. 

The thermodynamic compatibility of biological and synthetic polymers is a common question.993 Beijerinck,994 and Ostwald and Hertel,995 studied the thermodynamic compatibility of proteins and polysaccharides, and the latter authors evaluated the role of the source of starch. In contrast to cereal starches, potato starch is compatible with proteins in both acidic and basic media, whereas, Dahle991 reported that wheat starch sorbs proteins mainly in acidic and neutral solutions. 

Both amylose and amylopectin are hydrolyzed to glucose with cleavage of the glycosidic bonds. The human digestive system has the necessary a-glucosidase enzymes needed to catalyze this process. Bread and pasta made from wheat flour, rice, and corn tortillas are all sources of starch that are readily digested. 

Starch is one of the most commonly used excipients in the pharmaceutical industry due to its disintegration and binding properties. A number of sources of starch are commercially available, with corn starch being the most common. An overview of starches and starch derivatives and their use in the pharmaceutical industry is presented. 

Starch is second only to cellulose in natural abundance, and it is the major energy reserve in plants. The most important sources of starch are cereal grains, legumes, and tubers. The glucose polymers that make up starch come in two molecular forms, linear and branched. The former is referred... 

To outline the process, the aqueous substrate for beer production is made by brewing cereals with hops, which provide the characteristic bitter flavor component. Barley is the chief cereal ingredient, which is first malted to give enzymes required to breakdown starches to simple sugars, and also to contribute an important flavor component. Barley is a fairly expensive source of starch, so it is usually supplemented by the addition of less expensive starch adjuncts such as corn (maize), oats, millet, wheat, or rice. The adjunct contributes to carbohydrates, but makes little contribution to the flavor. Various strains of yeasts selected for their efficient conversion of glucose to ethanol are refined by individual brewers to achieve desired product qualities. 

The choice of the main cereal component used is based on the lowest cereal cost on a starch content basis, since the sugar ultimately available for fermentation depends on the amount of starch hydrolyzed. Small amounts of a particular cereal, for example, rye for rye whiskey, corn for bourbon, may still be employed to provide the desired flavor element in the final beverage. Rye is used extensively by distillers in the areas where it is plentiful. Corn, wheat, millet (65-68% starch), rice, and potatoes also provide supplementary sources of starch for spirits production, depending on local cost, usage, and availability. Small amounts of hydrolyzed rye are sometimes used to favor initial yeast propagation (about 2% of the total starch input). 

The most common sources of starch in various regions of the world are potato, maize, cassava (manioc, tapioca, yucca), and rice. Popularity of a given starch and starchy plants do not go together. For instance, in many regions of the world wheat and rye are very commonly used. Wheat starch is only randomly isolated, and rye starch is only exceptionally available. Rye grains contain mucus, which seriously obstructs isolation of starch from this source. 

Early in the eighteenth century the potato began to be used as a cheaper source of starch than that of wheat, and potato starch is now made in far greater quantity than other kinds, especially in Germany. 

Starch is the most important polysaccharide and is formed by combining glucose molecules with a glycosidic linkage. Corn, potatoes, rice and the roots of plants and seeds are the main sources of starch. Starch is an essential nutritional resource. 

Generally, starches contain about 20 to 30% of amylose and 70 to 80% of amylopectin, and these concentrations change with the botanical source of starch. Cassava starch, sweet potato starch, com starch, and waxy com starch showed, respectively, 17.0, 20.7, 25, and less than 1% of amylose (28,29, 30). The ratio amylose/amylopectin is an important factor to consider for CD production. The helicoidal stracture of amylose with loops of six to seven glucose imits can contribute with action of CGTase on a- and 3-CD formation (2). 

An additional source of starch in the wet-end is returned size press starch, which can have a significant influence on wet-end operations and machine runnabihty. 

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