Pregelatinized starch is a modified form of starch that has undergone a thermal and mechanical process to rupture and gelatinize the starch granules, resulting in a product with cold-water solubility and thickening properties. This modified starch is commonly used in various industries, such as food, pharmaceutical, paper, and textiles, for its ease of use and versatility in applications such as thickening, stabilizing, binding, and emulsifying. It is available in different forms, including powder, flakes, and granules, and can be derived from various sources such as cassava, corn, potato, and rice.
Properties
Pregelatinized starch has several properties that make it useful in various industries. Here are some of its properties:
- Cold-water solubility: Pregelatinized starch is instantly soluble in cold water, which makes it easy to use in a variety of applications.
- Thickening and gelling ability: Pregelatinized starch has thickening and gelling properties that are useful in food and industrial applications. It can be used as a thickener in sauces, gravies, and soups, and as a gelling agent in desserts, confections, and other food products.
- Lack of birefringence: Pregelatinized starch particles do not exhibit birefringence, meaning that they do not have the characteristic optical properties of crystalline materials. This property makes it useful in certain industrial applications.
- Reduced molecular weight: During the pregelatinization process, starch undergoes depolymerization, resulting in a reduced molecular weight. This property can make pregelatinized starch easier to digest and can also affect its functional properties.
- Reduced intrinsic viscosity: Pregelatinized starch generally has a lower intrinsic viscosity than its native counterpart, which can affect its functional properties.
- Swelling power: Pregelatinized starch has a high swelling power, which is a measure of the amount of water absorbed by the starch granules during cooking. This property makes it useful in certain food and industrial applications.
Production
Pregelatinized starch is produced by subjecting native starch to heat and moisture, causing the granules to swell and then burst. This results in the formation of a viscous paste, which is then dried and ground into a fine powder. There are several methods for producing pregelatinized starch, including:
- Drum Drying: In this process, a slurry of starch and water is fed onto a slowly rotating heated drum. The heat causes the water in the slurry to evaporate, leaving behind a dried sheet of starch. The dried starch is then ground into a powder.
- Extrusion Cooking: In this method, the starch is mixed with water and then fed into an extruder, where it is subjected to high heat and pressure. The starch undergoes a series of physical and chemical changes, resulting in a highly viscous paste. The paste is then dried and ground into a powder.
- Ohmic Heating: This is a newer method for producing pregelatinized starch. In this process, an electric current is passed through a slurry of starch and water. The current causes the starch to heat up rapidly, resulting in gelatinization. The gelatinized starch is then dried and ground into a powder.
Regardless of the method used, the resulting pregelatinized starch is a white, odorless, and tasteless powder with excellent cold-water solubility and thickening properties.
Applications
Pregelatinized starch has many useful applications, including as a thickener and gelling agent in food and beverage products, as a binder and filler in pharmaceutical tablets, and as a coating and sizing agent in papermaking. It is also used in industrial applications such as metal casting and in the production of adhesives, cosmetics, and personal care products. In this way, pregelatinized starch has become an important ingredient in many different industries.
Food industry
Pregelatinized starch has a wide range of applications in the food industry due to its ability to improve texture, viscosity, and stability. It is used as a thickener, binder, stabilizer, and filler in various food products such as soups, sauces, gravies, bakery products, and confectionery items.
In the dairy industry, pregelatinized starch is used in the production of cheese, yogurt, and ice cream to improve the texture and prevent syneresis. It is also used in the production of instant desserts and puddings.
Pregelatinized starch is also used in the meat industry as a binder and stabilizer in meat products such as sausages, meatballs, and canned meat.
In the beverage industry, pregelatinized starch is used as a stabilizer in soft drinks and fruit juices to prevent sedimentation. It is also used in the brewing industry to improve the clarity and stability of beer.
Other applications of pregelatinized starch in the food industry include the production of instant noodles, snacks, and pet foods.
Aquatic animal feeds
Pregelatinized starch has several applications in the aquatic animal feed industry. Some of these applications include:
- As a binder: Pregelatinized starch is often used as a binder in aquatic animal feeds. The starch can be used to bind different feed ingredients together, making it easier to form pellets.
- As a source of energy: Pregelatinized starch is a good source of energy in aquatic animal feeds. The starch is easily digestible and can provide a quick source of energy for the animals.
- As a source of carbohydrates: Pregelatinized starch is also used as a source of carbohydrates in aquatic animal feeds. The starch can provide a source of energy for the animals and can also help to maintain the proper balance of nutrients in the feed.
- As a thickener: Pregelatinized starch can also be used as a thickener in aquatic animal feeds. The starch can help to improve the texture and consistency of the feed, making it more palatable to the animals.
- As a source of nutrients: Pregelatinized starch can also be used as a source of nutrients in aquatic animal feeds. The starch can be fortified with vitamins and minerals, making it a good source of essential nutrients for the animals.
Mosquito repellents
Pregelatinized starch is often used as a binder in mosquito repellent formulations. The pregelatinized starch helps to hold the active ingredients and other components together, forming a solid mass or pellet that can be used as a slow-release mosquito repellent. Pregelatinized starch is also used as a thickener and stabilizer in mosquito repellent lotions and sprays, helping to provide a smooth and consistent texture to the product. Additionally, pregelatinized starch may have some natural insect-repelling properties, which could potentially enhance the effectiveness of the mosquito repellent.
Metal casting
Pregelatinized starch is also commonly used in the metal casting industry. In this application, it is used as a binder to hold the sand molds together. The starch is added to the sand, and then the mixture is formed into molds for casting metal parts. Pregelatinized starch is particularly useful in this application because it is easy to handle, has good binding properties, and can be burned out of the mold cleanly without leaving any residue. Additionally, it can be mixed with other binders such as clay or synthetic resins to produce molds with different properties. Overall, pregelatinized starch is a versatile and widely used ingredient that has many different applications in a variety of industries.
Pharmaceutical
Pregelatinized starch is a versatile excipient widely used in the pharmaceutical industry for its functional properties. It has various applications and modifications, including:
- Tablet and capsule filler/diluent: Pregelatinized starch is used as a filler in tablets and capsules to improve their flowability, compressibility, and solubility.
- Wet granulation binder: It is used as a binder in wet granulation processes to improve the content uniformity of tablets and capsules.
- Disintegrating agent: Pregelatinized starch is used as a disintegrating agent to facilitate the dissolution of tablets and capsules.
- Co-processed excipient: Pregelatinized starch can be co-processed with other excipients like microcrystalline cellulose to form a composite excipient that combines the advantages of both components, improving the compressibility, flowability, and disintegration time of the final product.
- Self-lubricating excipient: Pregelatinized starch has a natural self-lubricating property that reduces friction between particles, facilitating the manufacturing process.
- Partially pregelatinized starch: Partially pregelatinized starch is used in oral dry powder hard capsule formulations.
- Fully pregelatinized starch: Fully pregelatinized starch is mainly used as a binder in wet granulation processes taking advantage of the higher content of soluble fractions and tackiness.
Modifications of pregelatinized starch can include co-processing with other excipients, spray-drying, and cross-linking, among others, to achieve specific properties such as improved flowability, compressibility, and solubility. Each modification has different effects on the properties of pregelatinized starch and is used for specific purposes in pharmaceutical formulations.
Alpha starch
Pregelatinized starch, also known as Alpha starch in some markets (such as Vietnam and Thailand), is sometimes referred to as “Alpha” solely in reference to a brand or company that produces pregelatinized starch.