Effects of various catalysts on acetylation reaction of corn starch
Date Issued
2012
Date
2012
Author(s)
Chi, Fan-Yi
Abstract
Acetylated starch is widely used in the food industry as well as in the non-food industry according to its different levels of degree in substitution. The goal of this research is to find a catalyst with good reaction efficiency that helps accelerate the reaction rate in glacial acetic acid environment to produce acetylated starch rapidly. Corn starch is used as a reaction matrix, acetic anhydride as the reagent, and different materials as catalysts (sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, iodine), infiltrated in glacial acetic acid at 95 °C hot water bath, heated and stirred. The results shows that the experiment groups added with the catalyst is better than the control group without catalyst in the performance of reaction, while the auxiliary performance of each catalyst, sulfuric acid > nitric acid > phosphoric acid > iodine, and hydrochloric acid treatment group hydrolysis is very serious. Except for phosphoric acid treated group, the reaction rate of other groups decline as the mole number of acetic anhydride rises, and at the same time, according to the Fourier Transform Infrared Spectroscopy (FTIR) analysis, with the increase of degree of substitution, the signals at 1754, 1435, 1375, 1240cm-1 also increase. As for the optical properties, it can be clearly and easily observed that after the acetylation of starch, the phenomenon of birefringence is weakened, with the nitric acid treated group decreases most seriously. The Crystalline indicates that compared to the native corn starch collected from normal corns, the index of acetylated starch is smaller. Under the degree of substitution 0.4, the crystalline index of nitric acid treated group is the smallest, and it decreases 56% compared to the native corn starch. While under the degree of substitution 0.5, the crystalline index of non-catalyst treated group is the smallest, which decrease 77% compared to the native corn starch. As for the swelling power of the acetylated starch, in the part of low substitution degree (said to be less than 1), shows an increasing inclination compared to the native corn starch. Especially the sulfuric acid treated group is the highest in the part of water solubility index. Lastly, the starch pasting profile indicates that acetylated starch shows a decreasing inclination in pasting temperature and peak temperature, and its setback is lower compared to the native corn starch.
Subjects
corn starch
glacial acetic acid
catalyst
acetylated starch
degree of substitution
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R99641029-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):4ff85220c2bf7c8fd648efc14b0cb5c6