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Study on the properties and application of high amylose corn starch


Abstract: high amylose corn starch contains high amylose ratio, which has the characteristics of fast gel, high gel strength and hardness, and high structural stability. High amylose corn starch is the raw material for the preparation of resistant starch, and has excellent film-forming properties. In China, the lack of high amylose corn varieties limits the research of high amylose corn starch. In recent years, breakthrough progress has been made in the breeding of high straight chain Maize in China, and high straight chain maize varieties have been bred. It is of great significance to seize this opportunity to carry out the research on high amylose corn starch.

In this paper, high amylose corn starch was extracted from high amylose corn which was bred by Professor Zhao Zengyu. The properties of high amylose corn starch were studied systematically, and some application research was carried out on this basis. Firstly, resistant starch was prepared from high amylose corn starch, and the effect of amylose content on the formation of resistant starch was studied; secondly, the processing conditions of degradable high amylose starch PVA plastic film were determined.

The main conclusions are as follows: 1. The maize with 63.53% amylose content was used as female parent and 41.81% as male parent. The average yield of Maize Hybrid with amylose content of 53.98% was 8169kg / hm2, which was 20% lower than that of traditional maize hybrids.

2. The shape of high amylose corn starch is mostly oblong and irregular. The diameter ranges from 2 to 24 μ m, with an average of 10 μ M.

3. Under normal pressure, the viscosity of high amylose corn starch * * is 320cp; after heat treatment, the peak viscosity of high amylose corn starch appears at 118 ℃, which is 620 CP. scanning electron microscope photos show that the starch granules have basically broken.

4. Differential scanning calorimetry (DSC) showed that high amylose corn starch had two absorption peaks at about 78 ℃ and 110-120 ℃.

The solubility of high amylose corn starch was 61.5% higher than that of common corn starch, while its swelling power and light transmittance were 64.1% and 55.6% lower than that of common corn starch, respectively. The viscosity of high amylose corn starch paste was increased by 50.0% by sucrose solution treatment and 26.3% by salt solution treatment.

6. The content of resistant starch in common corn starch was 9.09%, while that of high amylose corn starch was about 20%.

7. Resistant starch was prepared by hot pressing method with common corn starch and high amylose corn starch as raw materials. The UV Vis absorption spectrum of resistant starch was compared with that of pure resistant starch. The results showed that λ Max and peak shape of resistant starch were very similar, which showed that resistant starch was composed of amylose.

8. When the resistant starch was prepared under the same conditions, the viscosity of the resistant starch made from common corn starch decreased from 3000cp * 1200cp, but it was still 3.75 times higher than that of high amylose corn starch. The viscosity of high amylose corn starch decreased slightly to 256 CP before and after preparation.

9. Considering all the indexes, the combination of preparation of degradable film was determined as follows: high amylose corn starch and polyvinyl alcohol (PVA) were mixed in the ratio of 3:7, and 20% ethylene glycol was added to gelatinize tape casting film. The tensile strength is 7.85mpa, the elongation is 8.23%, the tear strength is 40.53n/mm, and the transmittance is 64.47%.



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