Starch defatted

Additives to starch exert varying effects on the kinetics of water sorption. For example, lipids do not significantly affect the content of adsorbed water. The mode of starch defatting can also influence moisture sorption by molecules of the defatting solvent occupying active centers of sorption.389 The addition of either sucrose or lipids to starch has the same effect on both branches of the hysteresis curve.386,398 Some additives, such as dimethyl sulfoxide or ammonium rhodanide, induce selectivity of the adsorption and solvation of starch 411 Sulfur dioxide accelerates water sorption regardless of the temperature.412 Pretreatment of starch with sulfur dioxide usually increases the water sorption.413 Studies on the sorption of components of water-alcohol mixtures are discussed in Section IV. 

Starch [9005-84-9] M (162.1)n. Defatted by Soxhlet extraction with Et20 or 95% EtOH. For fractionation of starch into "amylose" and "amylopectin" fractions, see Lansky et al. [J Am Chem Soc 71 4066 1949]. 

The Water Unextractable Solids were isolated from dehulled, defatted, untoasted soy bean meal (particle size < 0.5 mm) by removal of cold water solubles, proteins and starch. The soy bean meal was extracted with cold water, a solution containing sodium dodecylsulphate and 1,4-dithiothreitol, and incubated with a-amylase, to yield the CWS, SDSS and HWS... 

To determine the amylose content of starch, the iodine reaction has been most commonly used because amylose and amylopectin have different abilities to bind iodine. The methods such as blue value (absorbance at 680 nm for starch-iodine complex using amylose and amylopectin standards), and potentiometric and amperometric titration have been used for more than 50 years. These procedures are based on the capacity of amylose to form helical inclusion complexes with iodine, which display a blue color characterized by a maximum absorption wavelength (kmax) above 620 nm. During the titration of starch with iodine solution, the amount (mg) of iodine bound to 100 mg of starch is determined. The value is defined as iodine-binding capacity or iodine affinity (lA). The amylose content is based on the iodine affinity of starch vs. purified linear fraction from the standard 100 mg pure linear amylose fraction has an iodine affinity of 19.5-21.0mg depending on amylose source. Amylopectin binds 0-1.2mg iodine per 100mg (Banks and Greenwood, 1975). The amylose content determined by potentiometric titration is considered an absolute amylose content if the sample is defatted before analysis. 

Starches were defatted prior to amylose estimation using the method outlined in the Basic Protocol. 

The defatted starch should not be removed from the thimble until contents have been air-dried for at least 12 hr. Removal prior to this would result in contamination of starch with cellulose from the thimble. The dried defatted starch should be in the form of a free flowing powder. The presence of aggregated starch clumps would result in the formation of insoluble gels during step 9. 

Detection and Determination of Starch.—(a) Qualitative test. A freshly-cut surface of the sample is treated with a few drops of iodine solution to see if a blue coloration is formed. If the result of this test is doubtful, a quantity of the dry, defatted substance is triturated well with a little water, and after depositing for a short time, the turbid liquid examined under the microscope. A little iodine solution is then added and the sped-men again examined microscopically for stained starch granules. 

Ingredients. All ingredients were obtained commercially along with compositional information and consisted of corn starch (National Starch, Bridgewater, NJ), whey protein concentrate (WPC) and sodium caseinate (SC) (Leprino Foods, Denver, CO), defatted soy flour (DSF) (Archer Daniels Midland, Decatur, IL), soy protein concentrate (SPC) (Central Soya Company, Fort Wayne, IN), and gluten (G) (Ogilvie Mills Ltd., Montreal, Canada). 

The high lipid content of oat starch is reflected in the high value of the transition enthalpy (AHCX) measured for the amylose-lipid complex (Table 15.4). This transition is reversible, and on a rerun greater AHCX, as well as Tcx (endotherm peak temperature), was found.26 When the oat starch was defatted, the endotherm assigned to the amylose-lipid complex disappeared from the DSC thermogram.26 Extraction at room temperature with 1-propanol water (3 lv/v) did not influence the thermogram of the starch, but if the starch was refluxed in the same solvent, a decrease in AH and a complete elimination of the endotherm ascribed to the amylose-lipid complex occurred.28 For oat starches with a lipid content of 1.1-1.7%, it was possible to... 

The preparation of starch-fatty acid complexes is based on the use of hydrophobic solvents, which in turn open the starch lattice for penetration by acids. Such solvent molecules can become guests of inclusion complexes and are subsequently displaced by fatty acids. Extrusion has been found useful for the synthesis of such complexes.748,749 Starch should be defatted prior to complexation by using methanol,739,740 Cellosolve, or 80% 1,4-dioxane.750-752 Table XXXV summarizes the results of a classical preparation.701 As shown in Fig. 47, the amount of complex formation by extrusion is not linearly proportional to the concentration of fatty acids added.749 In... 

Fig. 33.—Effect of lipid on starch retrogradation, measured as changes in the degree of gelatinization during the storage of cooked rice. Solid points, native rice open points, defatted rice solid squares, refatted rice. (Reprinted with permission from Y. Hibi, S. Kitamura, and T. Kuge, Cereal Chem., 67 (1990) 7-10.)...

The formation of starch complexes with other polysaccharides is perhaps best evidenced by the sorption of starch on cellulose and its derivatives. This sorption is selective with respect to amylose and amylopectin.1065 1066 Cotton fibers selectively adsorb amylose and not amylopectin.1667-1071 However, this method cannot be used for starch fractionation because cotton was considered to induce degradation (hydrolysis).1067 On the other hand, a method of purifying amylopectin that involves sorption of amylose on defatted cellulose has been published.1072 Reversible adsorption of amylopectin on cellulose occurs when starch is equilibrated with urea in 32-35% ethanol. There are also published attempts to separate starch components on filter paper.1073-1076 The reverse idea is applied in the stabilization of nitrocellulose by its sorption on starch.1077... 

Suknark, K., Phillips, R.D., and Chinnan, M.S. (1997). Physical properties of directly expanded extrudates formulated from partially defatted peanut flour and different types of starch. Food Res. Ini. 30, 575-583. 

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