Waxy maize

Similar materials are available based on potato starch, eg, PaseUi SA2 which claims DE below 3 and has unique properties based on its amylose—amylopectin ratio pecuhar to potato starch. The product contains only 0.1% proteia and 0.06% fat which helps stabilize dried food mixes compounded with it. Another carbohydrate raw material is waxy-maize starch. Maltodextrias of differeat DE values of 6, 10, and 15, usiag waxy-maize starch, are available (Staley Co.). This product, called Stellar, is offered ia several physical forms such as agglomerates and hoUow spheres, and is prepared by acid modification (49). Maltodextrias based oa com starch are offered with DEs of 5, 10, 15, and 18 as powders or agglomerates (Grain Processing Corp.). 

In industrial production of acid-modified starches, a 40% slurry of normal com starch or waxy maize starch is acidified with hydrochloric or sulfuric acid at 25—55°C. Reaction time is controlled by measuring loss of viscosity and may vary from 6 to 24 hs. For product reproducibiUty, it is necessary to strictly control the type of starch, its concentration, the type of acid and its concentration, the temperature, and time of reaction. Viscosity is plotted versus time, and when the desired amount of thinning is attained the mixture is neutralized with soda ash or dilute sodium hydroxide. The acid-modified starch is then filtered and dried. If the starch is washed with a nonaqueous solvent (89), gelling time is reduced, but such drying is seldom used. Acid treatment may be used in conjunction with preparation of starch ethers (90), cationic starches, or cross-linked starches. Acid treatment of 34 different rice starches has been reported (91), as well as acidic hydrolysis of wheat and com starches followed by hydroxypropylation for the purpose of preparing thin-hoiling and nongelling adhesives (92). 

Starch acetates [9045-28-7] are made by reaction of starch with acetic anhydride. Starch acetates are used in foods to provide paste clarity and viscosity stabiHty at low temperatures. A waxy maize starch acetate is most commonly used. Waxy maize starch acetates for food use are often cross-linked. Acetylated starches are also widely used in warp sizing of textiles. 

Definite proof that the interchain linkage is 6 —> 1-a-D has been obtained by Wolfrom and coworkers,91 who have isolated crystalline /3-isomaltose [6-0-(/3-D-glucopyranosyl)-D-glucose] octaacetate (in 1 % yield) from the mild acetolysis of waxy maize starch and have presented evidence that... 

In this connection, it should be noted that Wolfrom and Thompson9611 have recently claimed the isolation of 0.1% of nigerose (a 3 — 1-a-disac-charide) from the hydrolysis of waxy-maize starch. 

Although it has been found that the separated amylose component can be readily orientated to yield fiber patterns, amylopectin usually gives poor or amorphous patterns. In the granule, however, amylopectin does exhibit crystallinity, since waxy maize starch gives a diffraction pattern and other waxy starches behave similarly.193 -195 (This suggests that the branch points in the amylopectin molecule may be in the amorphous part of the granule.)... 

The only example of this technique applied to the amylose component is that already described, of the action of Z-enzyme on the /3-limit dextrin. In the case of amylopectin, enzymic methods enable a distinction to be made between the proposed laminated and highly ramified structures (I and III, in Fig. 1, page 352). The method used by Peat and coworkers101 involves the successive action of /3-amylase and R-enzyme on waxy maize starch. /3-Amylolysis will degrade A-chains down to two or three units from the 6 —> 1-a-D interchain linkages. These latter linkages will protect the... 

Starch is the major energy store of plants chemically it is a polymer of glucose and occurs in two separate forms, amylose and amylopectin. The ratio of the two types depends on the plant that the starch has come from typically starch is 20 30% amylose and 70-80% amylopectin but there are amylomaizes with more than 50% amylose while waxy maize produces almost pure amylopectin with less than 3% amylose. 

The ratio of amylose to amylopectin produced by a plant is under genetic control. Waxy maize is a natural mutation of maize that happens to produce almost pure amylopectin. 

If starch with different properties is required then either a different plant source must be used, e.g. waxy maize instead of potato, or a way of altering the starch produced by a plant must be found. 

Starches with modified properties can be obtained in several ways. One way is to use a source with starch that has different properties. Examples of this are waxy maize, which gives almost pure amylopectin, and tapioca. These are still starch in food law. 

The variation between the starch from different plants is considerable. The percentage of amylose varies from 27% in maize starch through 22% in potato starch to 17% in tapioca starch. The waxy maizes are unusual in that they are almost pure amylopectin. This is extremely convenient because it avoids the need to separate amylopectin from amylose chemically. 

Obtaining Different Properties in the Starch. One method of obtaining a starch with different properties is the biological method of using a different type of plant. The best example of this is waxy maize, which yields a starch that is nearly pure amylopectin. The other method is to chemically modify the starch. Chemically modified starch is normally declared as modified starch . A whole range of modified starches are available. There is of course no bar to chemically modifying a starch from a special source. 

Non-gelling Starches. These products are intended for uses where the starch replaces a gum like gum acacia. A typical product for this use might be an oxidised waxy maize starch. 

Amylodextrins from waxy-maize starch (A type) and potato starch (B type) retain the same diffraction pattern as that of the parent starch. On separation of a starch to give an amylodextrin, the... 

Products.—Considerable information concerning the mechanism of the enzymic hydrolysis of starch has been obtained from investigations of the action of purified maltase-free pancreatic amylase on a number of different substrates. The substrates studied were ordinary unfractionated but exhaustively defatted10 potato and com starches a branched chain substrate, waxy maize starch and amylose, the linear component of corn starch.41 69 eo f4 These investigations included comparisons not only of the rates of the hydrolysis of the different substrates but also of the products formed from them. 

With the same concentration of pancreatic amylase reacting under comparable conditions, no marked differences were observed in the rate of the hydrolysis of any of the unfractionated ordinary starches studied.41,69 6064 On the other hand significant differences were observed in the rate of the hydrolysis of straight and of branched chain substrates. The data60 in Table IV show that waxy maize starch is hydrolyzed more slowly than unfractionated corn starch and much more slowly than the... 

A Comparison of the Action of Purified Maltase-free Pancreatic Amylase on Waxy Maize Starch and on Other Substrates (Data of Mindell, Agnew and CcddwellM)... 

The data given in Table V show not only that pancreatic amylase hydrolyzes unfractionated starch and a linear substrate at different rates but also that, for equivalent time intervals with the same concentration of pancreatic amylase, the relative concentrations of the products formed from these two substrates differ. In addition, Table VIM,M summarizes comparative data for the products of the hydrolyses of potato starch, of com amylose, and of waxy maize starch when equivalent numbers of glucosidic linkages of these substrates had been broken. 

Not only does glucose appear somewhat earlier but also it is liberated in higher concentrations in the hydrolyzates from potato starch than in those from amylose. In addition, Table VI presents evidence for the more rapid liberation of glucose from waxy maize starch than from... 

Products Formed from Potato Starch, from Waxy Maize Starch and from Corn Amylose by Purified Maltose-free Pancreatic Amylase... 

Waxy maize starch Potato starch Amylose ... 

Waxy maize starch Potato starch Amylase Waxy maize starch Potato starch Amylose Waxy maize starch Potato starch Amylose... 

Angellier-Coussy,H.,Putaux, J.-L.,Molina-Boisseau,S.,Dufresne,A.,Bertoft,E., Perez,S. (2008). The molecular structure of waxy maize starch nanocrystals. Carbohydr. Res. (In press). 

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