Research Progress of Modified Corn Starch

Research Progress of Modified Corn Starch

 

The annual output of corn in our country is about 120,000,000 tons and ranks second in the world. It has great potential of development for the low cost. Due to the abundance of corn resources and high content of starch in corn, with the average content of 71.6%, the modern starch industry mainly uses corn. Corn processing represents both the extension and deepening of agricultural production and the upstream industry of industrial processing.

 

Based on the intrinsic properties of corn starch, physical and enzymatic processing methods can be utilized to improve the performance of starch and to expand the application range by changing the natural properties of starch, adding certain functions or introducing new properties to it and making it better meet application demands. Such products with secondary processing and changed properties are collectively called modified corn starch.

 

Techniques of Modified Corn Starch

1. Corn Starch of Hydrothermal Treatment

Hydrothermal Treatment refers to a physical method of treatment of starch under the condition of excessive or moderate water (with a moisture content greater than or equal to 40%) and at a certain temperature range (higher than glass-transition temperature but lower than gelatinization temperature).

Hydrothermal treatment is a simple physical modified method of starch and includes annealing treatment, heat-moisture treatment, and autoclaving treatment. Besides, the physical and chemical properties of starch will change after hydrothermal treatment.

The process of hydrothermal treatment only involves water and heat and doesn’t use organic agents or chemical reagent, so it is purely natural and pollution-free. Meanwhile, distinct changes of starch properties can be observed in the hydrothermal treatment, especially the autoclaving treatment, so it is an important technique of physical modified starch. Especially in the production of food additives, modified starch shows distinguished superiority. In the context of vigorously advocating green food at present, hydrothermal treatment is an effective production method of modified starch and worth popularizing and applying.

 

2. Oxidized corn starch

Oxidized starch is a product generated by the chemical action of starch and oxidants, usually sodium hypochlorite and calcium hypochlorite in the acid, alkaline or neutral medium.

After oxidation treatment, the introduction of carboxylic acid groups will lead to the decrease of viscosity, high fluidity, the increase of transparency and the increase of retrogradation, of starch paste and will also display favorable fluidity and film forming properties. In addition, the ageing resistance, anti-retrogradation property and acid resistance of starch can be greatly improved.

 

3. Prospect

Due to the high yield and low cost, corn is the main raw material in the modern starch industry. However, the properties of modified corn starch are different from those of corn starch because the former introduces such hydrophilic groups as hydroxypropyl, carboxymethyl and phosphate groups and this improves the polarity and hydrophilicity of starch. Furthermore, it has favorable freeze-thaw stability, anti-retrogradation property and relatively high degree of swelling and transparency. Consequently, modified corn starch has greater application prospects.

Social Share Counters

On May 23rd, 2013, posted in: Products and Techniques by Tags:

Comments are closed.