HPMC, or hydroxypropyl methylcellulose, is a type of cellulose derivative commonly used as a thickening agent, emulsifier, and stabilizer in a variety of products. It is a white, odorless, tasteless powder that is soluble in cold water and insoluble in hot water.
HPMC is available in a variety of grades, each with its own unique properties and applications. The grades of HPMC are based on the degree of substitution (DS) of the hydroxypropyl groups, which is a measure of the number of hydroxypropyl groups per anhydroglucose unit. The higher the DS, the more hydroxypropyl groups are present and the more hydrophilic the HPMC is.
The grades of HPMC are divided into three main categories: low DS, medium DS, and high DS.
Low DS HPMC is typically used in applications where low viscosity and low gel strength are desired. This grade is often used in food and beverage applications, such as ice cream, sauces, and gravies. It is also used in pharmaceutical applications, such as tablets and capsules.
Medium DS HPMC is used in applications where higher viscosity and gel strength are desired. This grade is often used in food and beverage applications, such as jams and jellies, as well as in pharmaceutical applications, such as ointments and creams.
High DS HPMC is used in applications where very high viscosity and gel strength are desired. This grade is often used in food and beverage applications, such as cheese and yogurt, as well as in pharmaceutical applications, such as suppositories and pessaries.
In addition to the three main categories of HPMC, there are also several subcategories. These subcategories are based on the degree of substitution, the particle size, and the type of hydroxypropyl group.
The degree of substitution subcategories are based on the degree of substitution of the hydroxypropyl groups. These subcategories are low DS (0.5-1.5), medium DS (1.5-2.5), and high DS (2.5-3.5).
The particle size subcategories are based on the size of the particles. These subcategories are fine (less than 10 microns), medium (10-20 microns), and coarse (more than 20 microns).
The type of hydroxypropyl group subcategories are based on the type of hydroxypropyl group present in the HPMC. These subcategories are hydroxypropyl methylcellulose (HPMC), hydroxypropyl ethylcellulose (HPEC), and hydroxypropyl cellulose (HPC).
HPMC is a versatile and widely used ingredient in a variety of products. The different grades of HPMC are based on the degree of substitution, particle size, and type of hydroxypropyl group, and each grade has its own unique properties and applications.