Comparison of Performance Indexes between Corn Starch and Cassava Starch

Comparison of Performance Indexes between Corn Starch and Cassava Starch

With the market-oriented reform of Chinese corn in 2016, the price of Chinese corn starch has dropped sharply. The price advantage brought about by the drop in price over tapioca starch has led to some new demands. A large amount of corn starch is used to replace tapioca starch in the fields of food, paper making and adhesives.  Flooding in Thailand in 2017 resulted in a shortage of cassava and a sharp rise in cassava starch, which remained high.  China's corn starch has also been exported to Southeast Asia in large quantities, replacing cassava starch on a large scale in the fields of food and starch deep processing.  The following little weaving tape gives you a brief understanding of the performance index differences between corn starch and tapioca starch:

Starch (C6H10O5)n

It is a natural macromolecule carbohydrate (white powder).  It is mainly extracted from corn, sweet potato, Ma Ling potato and wheat. It has no adhesive property. In order for starch to play an adhesive role, it must be dispersed in water to form a granular suspension and decocted into a colloidal dispersion. The decocted form is commonly referred to as gelatinized starch.

Starch paste:

During starch gelatinization, the hydrophilicity of starch particles is enhanced, and starch molecules (amylose molecules and amylopectin molecules) are fully extended, so that the carrier part presents a large viscosity. Then, the starch solution (carrier) with this property is mixed with ordinary raw starch (main body) uniformly. Due to the high viscosity and water retention of the carrier, the raw starch particles in raw starch water can be suspended and generate initial viscosity. A certain initial viscosity is required during gelatinization, so as to facilitate uniform and reliable coating of glue solution on corrugated edges.

Bonding process:

Because of the penetration force of amylopectin molecules, amylopectin molecules have shapes such as the gripping force of branches. When starch particles penetrate into the inner sides of the face paper and the core paper of corrugated cardboard, they gradually expand under the action of temperature to reach the gelatinization temperature, and then begin to bond.  The moisture contained in the starch granules evaporates and is partially absorbed by the face paper and the core paper, and the starch glue connects the inner paper, the core paper, the corrugated paper and the face paper into a whole to achieve the purpose of adhesion.

The basic composition of starch.

The use difference of different starches

Corn starch and tapioca starch are the main starches used in glue making in China, which can be used to make paste well.

The main differences are:

Corn starch:

The particle size is small, and only when it expands to a certain extent can it produce viscosity. Therefore, the viscosity is slightly higher and its drying speed is slower. Therefore, the paste from the edge trimmer is wet, and generally, the paste consumption is slightly higher.

Cassava starch:

If the particle size is large and expands slightly, the paste will produce viscosity. Therefore, the viscosity is slightly lower and its drying speed is faster. Therefore, the paste produced by the trimming machine is relatively dry. Generally speaking, the paste consumption is slightly lower.

Adverse Effects of Other Compounds in Starch

Lipid compounds:

1. It will inhibit the expansion and dissolution of corn starch granules, increase its gelatinization temperature and reduce its water binding capacity.

2. easy formation of amylose

The complex of lipid compounds increases the opacity or turbidity of starch paste and starch film, and also affects the thickening ability and adhesion ability of gelatinized starch.

3. Waxy corn starch and tapioca starch contain only a small amount of lipid compounds (about 0.1%), thus these adverse effects mentioned above will not occur.

Nitrogen-containing substances:

Because the protein content is the highest, the nitrogen content is usually referred to as the protein content.  The protein content of corn and wheat starch is higher than that of potato and cassava starch.

High protein content has many adverse effects, such as odor or other odor when used;  Foam is easily generated during cooking;  It is easy to change color during hydrolysis.  Both raw and cooked starches can significantly reduce the storage stability of starch glue.

Explanation: gelatinization temperature of starch

1. The temperature at which starch gelatinizes is called gelatinization temperature, and some are also called gelatinization temperature.  The gelatinization temperature of starch varies with different varieties, which is due to the different structural strength of starch granules and the different difficulty of water absorption and expansion.

2. Even if the starch of the same variety has different gelatinization difficulty of different granules, some can gelatinize at a lower temperature, others need a higher temperature to gelatinize, with a difference of about 10℃;  Larger particles are generally easier to gelatinize.

The gelatinization temperature of corn and wheat starch is higher than that of potato and cassava starch.  The gelatinization temperature of waxy corn starch is the same as that of common corn starch.  However, high amylose corn starch is difficult to gelatinize, even if it is heated in boiling water, it needs to be heated at a higher temperature under pressure.

3. The gelatinization temperature of starch has nothing to do with the concentration of starch milk.