Modified Starch

Modified Starch

Modified starch refers to products with changed properties of natural starch by means of physical, chemical and enzymatic methods. By the dissection, rearrangement and oxidation of molecules or the introduction of substituents into starch molecules, starch derivatives with changed, strengthened or new properties can be produced.

Different kinds of modified starch can be used in the same kind of food while the same kind of modified starch can be used in various kinds of food. Moreover, different manufacturers for the same kind of food have different usage habits. Even for the same kind of modified starch, different degrees of modification can make a big difference to the performance. Consequently, this provides a prospective future for the research, development and applications of modified starch in food quality and at the same time presents difficulty to the course.

Advantages of Modified Starch in Food

1. The use of modified starch enables the starch to maintain relatively high viscosity stability under the conditions of high temperature, high shear force and low pH value, and thus keep its thickening ability.
2. The modification treatment makes the retrogradation of starch difficult during room-temperature or low-temperature preservation to prevent the separation of water and mass resulting from retrogradation and gelatinization of food.

3. The modification treatment helps to increase the transparency of starch paste and then improve the appearance and gloss of food.

4. The modification treatment helps to improve the emulsifying property. The native starch molecule has no emulsifying property, so it cannot be used to form a stable water-oil mixed system. If the functional group with the duality of hydrophilic and oleophylic properties can be linked to the starch molecule, then it has both hydrophilicity and lipophilicity to emulsify and stabilize the water-oil mixed system.

5. The modification treatment also plays an important role in increasing starch concentration, reducing the starch viscosity and improving the gel-forming property of starch.

6. The modification treatment also helps to improve the starch solubility or swelling capacity in cold water and the processing property in food.

The modified starch used in the food industry mainly acts as the thickening, gelatinizing, binding and stabilizing agents. In replace of expensive raw materials, it can reduce the cost of food production and improve both the food quality and economic performance.

1. Application in Dairy Products
In dairy products, the modified starch is mainly used as gelatinizing, stabilizing and thickening agents and the commonly used varieties are cross-linked starch and hydroxypropyl starch.
1). In cheese products, it acts as the gelatinizing agent and enables the products to have favorable gelatinizing property so that to some extent it can reduce the usage amount of caseinate and the production cost.
2). In desserts, it mainly acts as the quality improver and enables the products to have viscosity, cream feeling and filament groups and then to increase the storage stability.
3). In yoghourt, it can be used as the stabilizing and thickening agents to improve the consistency and taste of products and reduce whey isolation.

2. Application in Beverages
In beverages, the stability and absorbability of modified starch are mainly utilized.
1). In drinks, it can be used as the stabilizing agent to improve the taste and posture and to hide the dry and astringent tastes.
2). In diary drinks, it can act as the stabilizing agent of emulsified flavor and partially replace expensive Arabic gum.
Modified starch is the general term of products generated by using physical, chemical and enzymatic methods to change the original properties of starch, such as dissolution characteristic, viscosity, taste, fluidity, gelatinization temperature and time. It has a great variety and different kinds of classification. According to the source of native starch, it can be classified into corn, potato, cassava, rice and wheat modified starch.

3. Difference form Native Starch
At present, in some undeveloped areas of the dairy industry, native starch is used in yoghurt as the thickening agent. Here a comparison is made between the effects of native starch and those of modified starch.
1). The addition of native starch makes yoghurt have a strong burnt smell and a rough and unsmooth taste while modified starch helps to reduce or avoid this phenomenon and to have a far better taste than that of native starch.
2). During the process of temperature reduction and refrigeration, the native starch is prone to aging, leading to the rough taste, the appearance of powders and the decrease of the viscosity, and thus harmful to the stability of the products. The modified starch, however, due to resistance-to-temperature change property, can maintain the viscosity stability of the system, reduce whey isolation and prolong quality guarantee period.
3). The observations under a microscope show that the swelling degree of modified starch is higher than that of native starch and prove that the water retaining capacity of the former is also stronger than that of the latter.

4. Comparison with Food Gums
The commonly used stabilizing agents in yoghurt are agar, PGA, gelatin, pectin and modified starch since these components won’t affect fermentation and have resistance to low temperature, low pH value and mechanical shearing. The modified starch used in yoghurt is a kind of edible modified starch. Compared with other gums, the main part of modified starch is the native starch. The modified starch to some degree can be completely digested and absorbed by the human body and the nutritional values and safety is the same as those of native starch, so the modified starch is a safe food additive.
The use of modified starch is very convenient and it works only after heating up and gelatinization. Usually, the compound of modified starch and gums can produce a synergistic effect. Because the price of modified starch is relatively low, so to some extent it helps to reduce the usage mount of gums and thus to reduce the production cost.

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On May 28th, 2013, posted in: Products and Techniques by Tags:

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