Enzymatic hydrolysis of starch

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. 

Fructose has a much sweeter taste than glucose, hence the transformation of glucose derived from enzymatic hydrolysis of starch from com, provides an alternative sweetener to sucrose (a disaccharide of glucose and fructose). This replaced the use of sugar cane by the US soft drinks and candy industry (and effectively destroyed the economy of Cuba in the process). 

Among the best known and most versatile hosts are the various cydodextrins [1,2] of which a-, P- and y-cyclodextrins are the most available. These are cyclic oligosaccharides built up of six, seven, or eight glucopyranose units, respectively. These compounds can be prepared by enzymatic hydrolysis of starch. The undoubtedly most important member of the cyclodextrin family is P-cyclodextrin (P-CD) which has become a cheap and easily available chemical, suitable for large scale applications. Schemes... 

Sucrose and lactose occur widely as the free sugars, lactose in the milk of mammals, and sucrose in fruit and plants (especially in sugar cane and sugar beet). Maltose is the product of enzymatic hydrolysis of starch, and cellobiose is a product of hydrolysis of cellulose. 

The applications of enzymes can be classified into three major categories industrial enzymes, analytical enzymes, and medical enzymes. In this chapter, we review several industrial processes, utilizing industrial enzymes such as starch conversion and enzymatic hydrolysis of celluloses. Before we discuss the enzymatic hydrolysis of starch and cellulose, we review the organic chemistry of carbohydrates. 

Combined Steam Pretreatment and Enzymatic Hydrolysis of Starch-Free Wheat Fibers... 

Maltose is a disaccharide (made of two sugar units) produced by the enzymatic hydrolysis of starch or cellulose, which are themselves polyacetals made up of a string of glucose units. 

The enzymatic hydrolysis of starch to glucose is commercially preferred to the acid hydrolysis route using hydrochloric acid. The enzymatic process produces fewer sideprod-ucts, does not involve a corrosive acid, and allows the use of less pure starch products whose protein contaminants would, upon acid hydrolysis, give amino acids and browning reactions. 

ENZYMATIC HYDROLYSIS OF STARCH. Starch is a substance used for storing energy reserve in plants, where it is deposited in the form of starch granules. Starch may be noticed in fruit juice as a milky haze. This haze disappears when the juice is heated, but re-appears after it is cooled to less than 10°C. Like pectin, starch has a protective colloid effect on suspended particles and thus makes juice clarification more difficult. 

The USPNF 23 describes dextrates as a purified mixture of saccharides resulting from the controlled enzymatic hydrolysis of starch. It may be either hydrated or anhydrous. Its dextrose equivalent is not less than 93.0% and not more than 99.0%, calculated on the dried basis. 

Dextrates is produced by controlled enzymatic hydrolysis of starch. The product is spray-crystallized, and may be dried to produce an anhydrous form. 

Dextrose, a monosaccharide sugar, occurs widely in plants and is manufactured on a large scale by the acid or enzymatic hydrolysis of starch, usually maize (com) starch. Below 50°C a-D-dextrose monohydrate is the stable crystalline form produced above 50°C the anhydrous form is obtained and at still higher temperatures P-D-dextrose is formed, which has a melting point of 148-155°C. 

Liquid glucose is prepared by the incomplete acidic or enzymatic hydrolysis of starch. 

Starch consists of polysaccharides, in fact of the branched amylopectin and the linear amylose (Figure 3.2). Starch can be obtained from very different plants, such as com, wheat, rice, and potatoes. Most of the starch raw material is used directly for food ( native starch ) only a small percentage is modified either by partial hydrolysis or by total saccharification, for example to glucose or fructose. The enzymatic hydrolysis of starch to high-fructose com syrup (HFCS) is described in Section 3.2.3.2. 

The carbon source most commonly used as a starting material is glucose, which is obtained by enzymatic hydrolysis of starch from corn, potato, and cassava. Waste molasses is also used since it is inexpensive, but it contains large amounts of biotin which inhibits the microbial glutamate synthesis. So it is necessary to add some other effective compounds to the medium to facilitate glutamate accumulation. 

P7-14 The enzymatic hydrolysis of starch was carried out with and without maltose and a-dextrin added, Adapted from S. Aiba, A. E, Humphrey, and N.F, Mills. Biochemical Engineering (New York Academic Press, 1973). 

Definition Purified mixt. of saccharides resulting from controlled enzymatic hydrolysis of starch either anhyd. or hydrated Properties Wh. free-flowing porous spherical gran., odorless, sweet taste producing cooling sensation in mouth freely sol. in water sol. in dil. acids and alkalis, basic org. soivs. insol. in common org. soivs. pH 3.8-5.8 (20%) DE 93-99%... 

Enzymatic hydrolysis of haemoglobin Enzymatic hydrolysis of starch... 

The glucose can be determined enzymatically with a colorimetric end point or titrimetrically commercial kits based on enzymatic hydrolysis of starch and measurement of glucose are currently available. 

Sucrose is extracted from sugar cane and sugar beets and is purified and sold in very large amounts for use in foods. Maltose (malt sugar) is made by the enzymatic hydrolysis of starch, which is a polyglucose. Lactose is the sugar in milk. It is not as sweet as sucrose. 

K. Nishinari, R. K. Cho, M. Iwamoto. Near Infra-red monitoring of enzymatic hydrolysis of starch Starch 41(3) 110-112,1989. 

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