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Effect of acetylation on the properties of corn starch
Ist Teil von
Food chemistry, 2008-02, Vol.106 (3), p.923-928
Ort / Verlag
Oxford: Elsevier Ltd
Erscheinungsjahr
2008
Quelle
Access via ScienceDirect (Elsevier)
Beschreibungen/Notizen
Acetylated corn starches with different degrees of substitution (DS 0.85, DS 1.78, DS 2.89) were synthesized by the reaction of corn starch with acetic anhydride in the presence of acetic acid under varying reaction temperatures. The product was characterized by FTIR spectroscopy,
1H NMR, X-ray diffraction and contact angle measurement. Acid-base titration and
1H NMR methods were employed to determine the degree of substitution of product. FTIR spectroscopic analysis showed that the characteristic absorption intensities of esterified starch increased with increase in the degree of substitution, and the characterized peak of hydroxyl group almost disappeared in the spectrum of DS 2.89 acetylated starch. The detailed chemical microstructure of native starch and acetylated starch was confirmed by
1H NMR,
13C NMR and
13C–
1H COSY spectra. Analysis of
1H NMR spectra of acetylated starches was assigned accurately. Strong peaks in X-ray diffraction of acetylated starch revealed that new crystalline regions were formed. Compared with native starch, the hydrophobic performance of acetylated starch esters was increased. The contact angle of acetylated starch with DS 2.89 was 68.2°.