Amyloses to amylopectin ratio

Both the amylose and amylopectin components of starch form complexes with iodine, but early studies showed that there is no connection between the iodine reaction and the reducibility of starch fractions.63 The complex of amylose is pure blue, whereas the complex of amylopectin is blue-violet.5864 Thus, the varying amylose-to-amylopectin ratio can be one of the factors responsible for the various shades of blue color exhibited by various varieties of starch. Amylopectin takes up less iodine than does amylose. Also the course of complex formation uptake is different, as is evident65 from Fig. 2. 

NMR spectrum depends on the type of starch (amylose-to-amylopectin ratio) and is associated with the numbers of carbon atoms in the branching points and thermal glucose units. Tables X and XI present 13C spin-lattice relaxation times (Tus) and nuclear Overhauser enhancement (n.O.e) for l3C nuclei of starches of various origins. Figure 21 shows H NMR spectra of amylose and a high-amylopectin waxy sorghum starch. 

It is known that the origin of starch controls the amylose-to-amylopectin ratio, the granule size, and other properties. The role of the origin of starch on water sorption-desorption (Tables XIV and XV) and related... 

The function of modified starch is dependent on a number of things the kind of starch (plant source), the amylose to amylopectin ratio, the nature of the substituents that are added, the degree of substitution, whether it is premodified by acid hydrolysis, and whether the starch is granular or gelatinized. 

Starch acetates are one of the more common derivatives of starch and are made from starches with a variety of different amylose to amylopectin ratios. The reaction differs from other substituted starches in that it is begun with a neutral water starch slimy (pH 7 to 8), which is then blended with acetic anhydride [Figure 14] (34), acetic acid (35), vinyl acetate (36), or a number of other acetyl donating reagents (37,38,39). 

Gelatinized materials with different starch viscosity, water solubility and water absorption have been prepared by altering the moisture content of the raw product and the temperature or the pressure in the extruder. An extrusion cooked starch can be solubilized without any formation of maltodextrins, and the extent of solubilization depends on the extrusion temperature, moisture content of starch before extrusion and the amylose to amylopectin ratio [5-9] (Fig. 2). 

Functionality factors include water absorption/hydration capacity, fat absorption, cooking time, protein functionality (amino acid and protein subunit composition), and starch functionality, which is associated with the amylose-to-amylopectin ratio. The amylose-to-amylopectin ratio affects the texture of cooked products. The texture of foods prepared from varieties with low amylose content tends to be stiffer than that of foods cooked from varieties with high amylose content. 

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