what is modified starch

Modified starch refers to starch that has undergone physical, chemical, or enzymatic modifications to alter its properties. These modifications are done to enhance the functional characteristics of starch, making it more suitable for specific applications in various industries, including food, pharmaceuticals, textiles, and papermaking.

There are several methods used to modify starch, and each method results in different properties. Some common modifications include:

1. Cross-linking: This involves chemically linking the starch molecules together to form a network structure. Cross-linked starch exhibits increased stability, resistance to heat, acid, and shear, and improved thickening properties. It is commonly used in applications where stability under harsh conditions is required, such as in canned foods and acidic sauces.

2. Hydrolysis: Enzymatic or chemical hydrolysis breaks down the starch molecules into smaller units, such as dextrins or glucose. This modification increases the solubility and viscosity of starch, making it suitable for applications like instant food products, beverages, and as a coating or glazing agent.

3. Substitution: Starch can be chemically modified by substituting some of its functional groups with other compounds. For example, acetylation involves the addition of acetyl groups to starch molecules, resulting in improved stability, film-forming properties, and reduced retrogradation (the tendency of starch to become firm or stale). Acetylated starch is often used in coatings, adhesives, and films.

4. Oxidation: Oxidized starch is produced by treating starch with oxidizing agents, which introduce carboxyl groups into the starch structure. This modification enhances the thickening and binding properties of starch, making it suitable for applications like sauces, soups, and bakery products.

5. Resistant starch: Resistant starch is a modified form of starch that is resistant to digestion in the small intestine. It acts as a dietary fiber, providing various health benefits such as improved digestion, reduced glycemic response, and potential prebiotic effects. Resistant starch is commonly used in products promoting digestive health or as a functional ingredient in low-carbohydrate food formulations.

Modified starch offers a range of functional properties, including improved stability, texture, solubility, thickening, gelling, and binding capabilities. The specific modification method used determines the properties and applications of the modified starch.