الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 112 |  |  |
| | | from | 112 | | |
Abstract
In this study, modified corn starch by acetylation, cross-linking and nano particles using different methodso of acetylation by acetic anhydride under alkaline conditions, cross-linking with sodium tri meta phosphate (STMP)/sodium tripolyphosphate (STPP) and nanoparticles by sodium hydroxide, 0.5 M concentration.
Experimental analysis were performed to investigate the effect of modification on a range of starch properties Water solubility, swelling power, paste clarity, granules size, degree of substitution (DS), degree of cross-linking (DC), Fourier transform infrared (FTIR) spectrometry, Wide angle X-ray diffraction, including granule morphology, scanning electron microscopy (SEM), molecular weight (MW), determination of amylose content, determination of amylopectin content, % degree of gelatinization (DG), color measurement, sediment volume, and compare them with those of the native corn starch.
Acetylation are chemical modifications which alter the properties of starch. The degree of modification of acetylated starch depend on the catalyst concentration. The objective of this study is to evaluate the effect of acetylation on the structural, morphological, physico–chemical properties of modified starch.
Corn starch was chemically modified by cross-linking with STMP/STPP (99:1 w/w) and the physicochemical properties of the cross-linked corn starch were investigated as a function of the degree of cross-linking. Cross-linking decreased the solubility, swelling factor, and paste clarity of corn starch. While the viscosity significantly increased from the native starch and is the swelling factor was highly correlated with the degree of cross-linking, the X-ray diffraction batterns did not show any significant alteration in the crystallinity of corn starch. It SEM measurement shouled a black zone on the surface of crossed-linked starch granules, which did not occur with native starch.
Nano materials already attract great interest because of their potential applications in technology, food science and medicine. Biomaterials are biodegradable and quite abundant in nature so, they are favored over synthetic polymer-based materials. Starch as a nontoxic, cheap and renewable raw material particularly, suitable for preparation of nanoparticles.the structure and some physicochemical properties of corn starch particles of the size between 13 to 30 nm, obtained by chemical and mechanical treatment of native starch, were presented. We demonstrated, using Scanning Electron Microscopy (SEM) and the non-contact Atomic Force Microscopy, that the shape and dimensions of the obtained nanoparticles both corn starch fit the block lets – previously proposed as basic structural features of native starch granules.