Pregelatinized starch is a kind of physical modified starch, which has the characteristics of convenience and economy, large viscosity, high viscoelasticity, and rapid pasting in cold water, etc. It has a wide range of applications in food.

Factors affecting the pasting degree of products

1.1 Raw materials

Starch varieties have a greater impact on the pre-gelatinized starch, mainly straight-chain starch and branched-chain starch ratio is different. Even if it is the same kind of starch, due to changes in origin and climate conditions, the composition of starch changes, and the products are difficult to paste and the degree of paste is also different. Starch particles of different sizes, also has an effect on the paste, large particles are easy to paste.

1.2 Slurry concentration

The determination of slurry concentration should not only consider whether the starch paste is the best state, but also consider the drying efficiency, cost reduction. Generally speaking, if the slurry concentration is adjusted upward, the paste degree of the product will be decreased.

1.3 Drying temperature

When the output is certain, the higher the drying temperature, the higher the degree of product paste.

1.4 Thickness of slurry film

If the slurry film is too thick, the pasting is difficult and uneven, and it is easy to have sandwich phenomenon. Roller speed, slurry concentration, feed amount and other factors affect the thickness of the slurry film.

1.5 Additives

Directly heated starch milk is only 80% pasted, in the process of starch pasting, add some additives to help improve the degree of pasting. Sodium bicarbonate, sodium hydroxide can reduce the degree of starch polymerization, so that the starch is easy to paste, the amount added for the dry starch weight of about 0.5%. Glycerol monostearate can be embedded with the spiral ring of straight-chain starch and inhibit the aging of starch, which is also conducive to the pasting of starch, and the added amount is 0.2%-0.5% of the weight of dry starch.

Properties and applications of pregelatinized starch

2.1 In the process of pre-gelatinization, water molecules destroy the hydrogen bond between starch molecules, thus destroying the crystalline structure of starch granules, so that the starch particles are lubricated and dissolved in water, and therefore easy to be acted by amylase, which is conducive to the digestion and absorption of the human body. This property of pregelatinized starch can be used to produce food for the elderly and infants.

2.2 Pregelatinized starch has strong water absorption, high viscosity and elasticity. It can be used in surimi series products, ham, salami and other food products to improve molding, enhance elasticity and prevent water loss, so that the products are full and smooth. Add 10%-40%, too high is easy to aging.

2.3 Pregelatinized starch water retention, used in baked goods, such as cakes, bread, add about 4% of the pregelatinized starch, so that the product can remain soft and fluffy, delay aging. In addition, it can be used as a moisturizing agent for icing on the surface of western-style pastries, and can also inhibit sucrose crystallization.

2.4 Pregelatinized starch has good freezing stability and can be used to stabilize the internal structure of frozen food. Adequate amount of pregelatinized starch is added in quick-frozen food. It can avoid the product cracking in the process of quick-freezing, improve the rate of finished products and thus reduce the production cost.

2.5 Pregelatinized starch is well dispersed and has a thickening and stabilizing effect, which is used in instant cereals, almond paste, chicken essence, jam and apple pie filling. It is generally used at 5%-10% in jam and sweet pie fillings.

2.6 Pregelatinized starch gels have some strength, and this blend of pregelatinized starches can be used as a substitute for gels for puddings.

2.7 Pregelatinized starch is soluble in cold water, eliminating the need for steaming and cooking, and is more economical than other food additives because of the abundance of raw materials and low price, so it is commonly used in convenience foods.

2.8 Others, adding appropriate amount of pregelatinized starch in noodles can reduce the breakage of noodles and cook them quickly.

Precautions for Selecting Pregelatinized Starch in Foods

3.1 When pregelatinized starch plays the role of adhesion in food, attention should be paid to the selection of natural starch raw materials, and the high content of branched-chain starch is strong adhesion.

Corn, wheat and other cereal starch paste viscosity is low, while potato and other potato starch paste viscosity is relatively high. In addition, the viscosity values of pre-gelatinized starch pastes are different for different processing methods. Generally speaking, the pregelatinized starch produced by extrusion type has lower viscosity than the product of drum type, and the product particle size also has influence on the viscosity, fine particle size, low viscosity of hot paste, high viscosity of cold paste, and the opposite is true for coarse particle size.

3.2 Some foodstuffs also have certain requirements on the transmittance of pregelatinized starch, such as apple pie filling, which requires high transparency, and salad dressing, which requires low transmittance of pregelatinized starch. In general, the lower the content of straight chain starch, the better the light transmission. Potato and spicy corn starch pastes have better translucency than those of corn and wheat.

3.3 Food ingredients are complex and varied, in which salt, sugar, acid, etc. all affect starch paste. For example, the greater the content of salt and sucrose, the more difficult it is to paste the starch, and the aging is faster after paste. Therefore, the effect of other ingredients on the performance of starch must be considered when used in food.