Hydroxypropyl starch

Hydroxypropyl starch (HPS) is a chemically modified starch used in various industries due to its enhanced properties compared to native starch. It is produced by treating starch with propylene oxide, a process that introduces hydroxypropyl groups into the starch molecule.

Production

The production of hydroxypropyl starch involves the reaction of starch with propylene oxide in an alkaline medium. This process is known as etherification, and it results in the introduction of hydroxypropyl groups into the starch molecule. The degree of substitution (DS), which refers to the average number of hydroxypropyl groups per glucose unit in the starch, can be controlled by adjusting the reaction conditions.

Properties

Hydroxypropyl starch has several properties that make it useful in various applications. These include improved solubility and stability, increased resistance to retrogradation, and enhanced thickening and binding abilities. The specific properties can vary depending on the degree of substitution and the type of starch used as the starting material.

Applications

Hydroxypropyl starch is used in a wide range of applications. In the food industry, it is used as a thickener, stabilizer, and emulsifier in products such as sauces, soups, and baked goods. It is also used in the pharmaceutical industry as a binder and disintegrant in tablet formulations. Other applications include use in the paper industry, in adhesives, and in the production of biodegradable plastics.

Health and Safety

As a food additive, hydroxypropyl starch is generally recognized as safe (GRAS) by the FDA. However, like all food additives, it should be used in moderation. In the industrial setting, proper safety measures should be taken when handling propylene oxide, as it is a flammable and potentially harmful substance.

See Also

• Starch
• Food additive
• Propylene oxide
• Etherification