01
Concept and characteristics of Modified Starch
In order to improve the properties of starch and expand its application range, physical, chemical or enzymatic treatment is used to introduce new functional groups into starch molecules or change the size of starch molecules and the properties of starch particles, so as to change the natural characteristics of starch (such as gelatinization temperature, thermal viscosity and its stability, freeze-thaw stability, gel force, film-forming property, transparency, etc.), making it more suitable for certain application requirements. This kind of starch that changes its properties after secondary processing is collectively referred to as modified starch.
Compared with ordinary starch, most of the modified starch obtained by appropriate modification has many excellent characteristics, such as high paste transparency, low gelatinization temperature, high viscosity and stability of starch paste, small retrogradation, excellent film-forming property, strong frost resistance, strong acid, alkali and mechanical resistance.
02
Application of modified starch in food
1. The good thickening, film-forming, stability and gelatinization properties of modified starch are mainly used in rice flour products. The main modified starch used are esterified starch and hydroxypropyl starch
1) The fried instant noodles with modified starch have crisp structure and low oil absorption, and the product has good quality and storage stability
2) Instant noodles can improve the rehydration, chewability and elasticity of noodles and reduce the cooking time
3) Adding modified starch to pasta can reduce oil absorption, improve the crispness of pasta and prolong the storage time of products
4) In the production of rice flour, as a tissue forming agent and a bonding agent, it can increase the transparency and smoothness of the products, reduce the viscosity and improve the taste.
2. In baking products, modified starch is mainly used for its good film-forming property, high-temperature expansibility and stability
1) It is used as a substitute for butter in cake and icing production to provide good capacity and structure and reduce human fat intake.
2) As a glazing agent in baked food, it can form a good, clear and bright film to replace expensive protein and natural glue.
3) As a stabilizer and thickener in fruit cakes, pies and fillings, it provides products with smooth and short silk structure to prevent layering and stuffing explosion.
In waffles, dough cookies and cookies, it can produce crisp texture, excellent color and good taste. In flour food, it can also increase the firmness and boiling resistance of products.
Crispy biscuits, rice fruits and other products require starch to have certain expansibility. Pregelatinized starch is the raw material of this kind of products, which is better than adding ordinary starch. The reason is that part of the starch in the mixture blank made of pre gelatinized starch has absorbed water, and a large number of water frozen starch particles will bubble out when baking, resulting in expansion. On the contrary, if ordinary starch is used, it starts to absorb water when baking, so it is not easy to achieve the purpose of crispness. Sometimes, in order to achieve better results, modified pregelatinized starch is also used.
3. In the application of frozen food, modified starch mainly plays the role of thickening, improving texture, anti-aging and improving sensory quality in most frozen food.
For example, the skin of Tangyuan is easy to crack after freezing, and it cannot be frozen and melted repeatedly. Adding about 5% etherified starch to glutinous rice flour for making glutinous rice dumplings can play a role in bonding and wetting, effectively avoiding skin cracking and starch retrogradation, reducing the phenomenon of soup paste during cooking and reducing the amount of solid in the soup.
4. The application in snack food mainly uses the good adhesion, swelling, brittleness and fluffy structure of modified starch. The commonly used modified starch includes pre gelatinized starch, etherified starch and composite modified starch
1) In extruded food, modified starch can make the products have good expansion degree and structure, and the strength and brittleness of the products are also improved. The products have uniform structure, high yield, and can increase functional fiber components at the same time
2) In microwave puffed food, modified starch can control the volume and structure of products and make the pores of products uniform
3) In crispy peanuts, modified starch can improve crispy tissue and give crispy light, crisp, crisp and fluffy structure
4) In other foods, modified starch can also play a good role
03
Development trend of modified starch
1. Development of new functional modified starch
Functional modified starch is mainly used in food, medical, pharmaceutical, daily chemical and other industries. It refers to modified starch that has certain health care and physiological functions for human body, as well as environmentally friendly starch based slow-release carriers, adsorption materials, biodegradable materials, such as resistant starch, slow digestion starch, porous starch, etc. The output of this kind of modified starch is not as large as that of ordinary modified starch, but it can significantly improve the quality and grade of processed products, and has high added value. It is the development trend of modified starch research at home and abroad.
2. Establish and improve the nutritional value and food safety evaluation system of modified starch
The edible denatured starch produced in developed countries has long been recognized by the WHO and FAO Expert Committee on food additives, and many products have been reviewed by FDA, and the corresponding use limits and usages have been formulated. Although China's "manual of food additives" also contains relevant contents about the dosage and usage of edible modified starch, there are few contents related to the nutritional value and safety of edible modified starch, and the safety evaluation system of edible modified starch is not perfect. In order to improve the edible safety of modified starch, we should deepen the research on the nutritional value of modified starch, establish and improve the edible safety evaluation system of modified starch. In terms of the production technology, production equipment and the development of new products of modified starch, there is also a large research space in China.
