Where does hydroxypropyl methylcellulose come from?

Chemical Structure

Link to Ding’ao

Origin

Hydroxypropyl Methylcellulose is obtained from various natural sources, mainly wood pulp and cotton linters. 1

Since , HPMC has been used as a gluten replacement for the manufacture of baked goods.3

Function

HPMC can serve several functions in baked goods such as:1, 2

• Stabilizer of emulsions and foams: critical for dough development during baking. 

• Thickener: increases viscosity by thickening the aqueous phase. 

• Fat-replacer: acts as a lubricant to help maintain creamy mouthfeel. 

• Gluten-substitute: most effectively when combined with carboxymethylcellulose (CMC) in baked goods. 

• Bulking agent

• Coating agent: film and barrier formation for coating. 

• Binder

• Water retention: extends shelf-life.  

• Controls water balance during freezing and thawing. 

Nutrition

HPMC is considered a non-fermentable soluble dietary fiber, thus providing several health benefits including reduction of total and low density lipoprotein cholesterol, reducing risk factors of type 2 diabetes and aiding intestinal movements.3

Using HPMC in gluten-free baked goods helps with diet management for patients with celiac disease.3

Commercial production 

HPMC is manufactured following this process:1, 2

• Alkalinization: wood pulp cellulose is treated with a 50 wt% sodium hydroxide solution in a reactor. 

• Etherification: addition of  methyl chloride followed by propylene oxide to introduce methoxy and propylene glycol groups, respectively. 

• Neutralization: using hydrogen chloride solution. 

• Purification: HPMC is washed several times with hot water, and  filtered. 

• Drying and sizing: the purified product is dried, ground to desirable particle size followed by packaging.

Application

HPMC can be used in the manufacture of several baked products, fillings, foams and coatings. It is a great alternative for gluten substitution in gluten-free baked products in combination with CMC. 

Some considerations when adding HPMC to food products include:1, 3

• Solubilizing HPMC/CMC before addition for full performance. 

• Consider the water activity of the systems, 5-10% of water may be needed in some formulations. 

• HPMC should be added after proteins are activated. 

• HPMC accommodates high sugar levels, up to 50%. 

Methods of incorporating of HPMC/CMC mixtures in food products:3

• HPMC/CMC should be dispersed in one third of the required water. 

• Add the rest of HPMC/CMC with the dry ingredients to avoid lump formation. 

• Disperse the blend in the required oil and then add to the bakery mix. 

Baked Goods Usage Level Effect Wheat Bread (reduced carbohydrate content) 1.0 %

• Improves texture
• Enhances high loaf volume.

Fruit Cake 0.3 %

• Improves texture
• Enhances high loaf volume.

Tortillas 0.075 % Pancakes (fat reduced) 0.25 % Waffles (fat reduced) 0.3 % Pastry dough 1.0 %

• Provides a desired layering structure
• Light and flaky texture.

Muffins (fat reduced) 0.4 %

• Enhanced textural properties
• High loaf volume.

Gluten-free Bread 1.0 &#; 1.4 %

• Enhanced textural properties
• High loaf volume.

Gluten-free Cake 1.0 %

Regulations

HPMC is permitted for its direct addition to food products by the FDA.4

In the EU, HPMC (E 464) is considered safe when used for its intended purpose.5  Accepted HPMC types must have between 19 -30 % methyl and 3 -12% hydroxyprop(ox)yl groups content. 

References

1. Wüstenberg, Tanja. Cellulose and cellulose derivatives in the food industry: fundamentals and applications. John Wiley & Sons, .
2. Intratec. Hydroxypropyl Methyl Cellulose Production. Intratec, San Antonio, . Accessed 8 Oct
3. Caballero, Benjamin, Paul Finglas, and Fidel Toldrá. Encyclopedia of food and health. Academic Press, .
4. Food and Drug Administration (FDA). US Department of Health and Human Services. CFR Code of Federal Regulations Title 21, Part 172 Food Additives Permitted For Direct Addition To Food For Human Consumption, https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=172.874  . Accessed 08 October .
5. European Commission (EC). Commission Regulation NO231/ laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No / of the European Parliament and of the Council . Official Journal of European Communities, 09 March .

Cellulose ether used as emulsifier or thickening agent to disperse colloids in water

"HPMC" redirects here. For other uses, see HPMC (disambiguation)

Chemical compound

Hypromellose (INN), short for hydroxypropyl methylcellulose (HPMC), is a semisynthetic, inert, viscoelastic polymer used in eye drops, as well as an excipient and controlled-delivery component in oral medicaments, found in a variety of commercial products.[1][2]

As a food additive, hypromellose is an emulsifier, thickening and suspending agent, and an alternative to animal gelatin.[3] Its Codex Alimentarius code (E number) is E464.

Chemistry

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Hypromellose is a solid, and is a slightly off-white to beige powder in appearance and may be formed into granules. The compound forms colloids when dissolved in water. This non-toxic ingredient is combustible and can react vigorously with oxidizing agents.[4]

Hypromellose in an aqueous solution, like methylcellulose, exhibits a thermal gelation property. That is, when the solution heats up to a critical temperature, the solution congeals into a non-flowable but semi-flexible mass. Typically, this critical (congealing) temperature is inversely related to both the solution concentration of HPMC and the concentration of the methoxy group within the HPMC molecule (which in turn depends on both the degree of substitution of the methoxy group and the molar substitution). That is, the higher the concentration of the methoxy group, the lower the critical temperature. The inflexibility/viscosity of the resulting mass, however, is directly related to the concentration of the methoxy group (the higher the concentration is, the more viscous or less flexible the resulting mass is)[citation needed].

Uses

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Are you interested in learning more about Hydroxy Ethyl Methyl Cellulose? Contact us today to secure an expert consultation!

There are many fields of application for hypromellose, including:[5]

• Tile adhesives
• Cement renders
• Gypsum products
• Pharmaceutical
• Paints and coatings
• Food
• Cosmetics
• Detergents and cleaners
• Eye drops
• Contact lenses
• Polyvinyl Chloride (PVC)[6]

Use in whole grain breads

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Agricultural Research Service scientists are investigating using the plant-derived HPMC as a substitute for gluten in making all-oat and other grain breads.[citation needed] Gluten, which is present in wheat, rye, and barley, is absent (or present only in trace quantities) in oat and other grains. Like gluten, HPMC can trap air bubbles formed by the yeast in bread dough, causing the bread to rise.

Use in construction materials

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HPMC is used primarily in construction materials like tile adhesives and renders[7] where it is used as a rheology modifier and water retention agent.

Functionally HPMC is very similar to HEMC (hydroxy ethyl methyl cellulose) Trade names include Methocel and Walocel. The global leading producer is now DuPont, formerly manufactured under Dow Wolff Cellulosics GmbH.[8]

Ophthalmic applications

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Hypromellose solutions were patented as a semisynthetic substitute for tear-film.[9] Its molecular structure is predicated upon a base celluloid compound that is highly water-soluble. Post-application, celluloid attributes of good water solubility reportedly aid in visual clarity. When applied, a hypromellose solution acts to swell and absorb water, thereby expanding the thickness of the tear-film. Hypromellose augmentation therefore results in extended lubricant time presence on the cornea, which theoretically results in decreased eye irritation, especially in dry climates, home, or work environments.[10] On a molecular level, this polymer contains beta-linked D-glucose units that remain metabolically intact for days to weeks. On a manufacturing note, since hypromellose is a vegetarian substitute for gelatin, it is slightly more expensive to produce due to semisynthetic manufacturing processes. Aside from its widespread commercial and retail availability over the counter in a variety of products, hypromellose 2% solution has been documented to be used during surgery to aid in corneal protection and during orbital surgery.

Excipient/tableting ingredient

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In addition to its use in ophthalmic liquids, hypromellose has been used as an excipient in oral tablet and capsule formulations, where, depending on the grade, it functions as controlled release agent to delay the release of a medicinal compound into the digestive tract.[11] It is also used as a binder[12] and as a component of tablet coatings.[13][14]

Test methods

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Various benchmark tests are used to qualify hypromellose:

• Viscosity
• Degree of substitution (DS)
• Molar substitution (MS)
• Salt content
• Moisture

Viscosity test methods

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Because hypromellose solution is a non-newtonian solution and exhibits pseudoplastic, more specifically, thixotropic behavior, various test methods are available, and the results of different methods and viscosimeters do not necessarily correspond to each other. Also, due to viscometer acceptable ranges of error, viscosity is typically given as a mean, or as a range. Typical viscosity test will specify the following:

• Solution concentration (1%, 2%, 1.9% bone dry, etc.)
• Viscometer (RheoSense m-VROC and microVISC, Brookfield LV or RV, Höppler falling ball, Haake Rotovisco, etc.)
• Viscometer spindle number (1 ~ 4 for Brookfield LV, 1 ~ 7 for Brookfield RV, etc.)
• Solution Temperature (20 °C, 25 °C, etc.)

Degree of substitution

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Degree of substitution is the average level of methoxy substitution on the cellulose chain. Since there are maximum three possible sites of substitution with each cellulose molecule, this average value is a real number between 0 and 3. However, degree of substitution is often expressed in percentages.

Molar substitution

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Molar substitution is the average level of hydroxypropoxy substitution on the cellulose chain. Since hydroxypropoxy base can be attached to each other on side chains and does not each require a base substitution site on the cellulose molecule, this number can be higher than 3. However, molar substitution is also often expressed in percentages.

Moisture

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Since all cellulose ethers are hygroscopic, they will absorb moisture from surroundings if left exposed from original packaging. Thus, moisture must be tested and weight corrected to ensure adequate amount of dry active material are apportioned for usage. Moisture is tested by weighing a sample of X grams on an analytic scale, and drying the sample in an oven at 105 °C for 2 hours, then weighing the sample again on the same scale.

See also

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References

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