Hydroxypropyl cellulose is a semi-synthetic substance that is produced by the reaction of raw cellulose (commonly derived from trees) with a mixture of phosphoric acid and water. Hydroxypropyl cellulose is insoluble in most solvents, usually used for thickening and stabilising various types of foods and beverages . It is also an excipient used in the manufacturing process of generic drugs as well as veterinary medicine.
The European food additive number for hydroxypropyl cellulose is E463 respectively.
What is hydroxypropyl cellulose?
Hydroxypropyl Cellulose (HPC) is a water-soluble polymer that’s made from the cellulose in wood pulp. It’s a common thickening agent used in foods and cosmetics.
HPC (high-substituted hydroxypropyl cellulose) and L-HPC (low-substituted hydroxypropyl cellulose) are two grades of hydroxypropyl cellulose. The former has more hydroxyl groups on its molecular chain than the latter, so it has more thickening power.
Let’s see the details.
HPC
HPC contains no free hydroxyl groups in its molecules, so it is generally not soluble in water. However, when it reacts with acids or bases, it will form salts or esters that can dissolve in water to give solutions of HPC.
The following is a specification of hydroxypropoxyl groups (HPC):
| Assay | Not more than 80.5 % |
| Numbers | Not more than 4.6 per anhydroglucose unit |
| Average Numbers | 3.5 hydroxypropoxy groups per anhydroglucose unit |
| Molecular Weight | From about 30,000 to 1,000,000 |
L-HPC
Low substituted HPC (L-HPC) has lower viscosity at normal temperature and higher water solubility than regular HPC, but can still form a gel network with high viscosity when exposed to heat or cooled down again after heating.
The full name of this additive is hydroxypropyl cellulose within a small portion of the anhydroglucose unit contains hydroxypropyl groups.. The E number E463a was introduced since 2018 and it is used as a binder and disintegrant in tablets or wafers containing dietary supplements of vitamins and/or minerals.
The following is a specification of hydroxypropoxyl groups (L-HPC):
| Other names | Cellulose, 2-hydroxypropyl ether (low substituted) |
| Assay | 5%-16% |
| Numbers | 0.1 to 0.4 per anhydroglucose unit |
| Average Numbers | 0.2 hydroxypropoxy groups per anhydroglucose unit |
| Molecular Weight | From about 30,000 to 1,000,000 |
What is hydroxyethyl cellulose do?
Hydroxyethyl cellulose is a kind of cellulose ether with good water solubility. It can be used as thickener, emulsifier and stabilizer in food products, such as ice cream, cake, candy, canned food and so on.
The main features are:
1. Non-toxic, tasteless and odorless;
2. Good stability to acidity and alkalinity;
3. Good compatibility with other food ingredients;
4. High viscosity, good suspension ability;
What is hydroxypropyl cellulose good for?
Hydroxypropyl cellulose is a water-soluble polymer that is used in food to thicken, stabilize and emulsify. It is also used in cosmetics to increase the viscosity of products. It works by forming a gel structure that traps water molecules in its matrix.
Hydroxypropyl cellulose can be used in a wide range of products including beverages, dairy products, baked goods, cereals and desserts. Due to its ability to gel at low concentrations and its resistance to fat absorption, hydroxypropyl cellulose is often used as an emulsifier in ice cream mixes. It also helps keep ice crystals small so that they melt quickly when consumed.
What is hydroxypropyl cellulose (E463) made from?
Hydroxypropyl cellulose is a cellulose ether produced from wood pulp by substituting hydroxyl groups for some of the carboxyl groups of the cellulose molecule. It is used as an anti-caking, water-retention and thickening agent in food products.
It is produced by reacting cellulose with propylene oxide in the presence of catalysts, e.g., sodium hydroxide or sodium methoxide:
Cellulose + 3 CH2CH2OH + 3 NaOH → C6H10O5(OH)3 + 3 NaC6H10O5
Generally, the production of ethers can be achieved by two steps: alkalinization and etherification.
Step 1: Alkalinization
In the Kraft process, cellulose pulp is prepared by dispersing it in an alkali solution. (generally sodium hydroxide, 5–50%).
Cell-OH+NaOH →Cell·O-Na+ +H2O
Step 2: Etherification
Cellulose reacts with propylene oxide under strictly controlled conditions in the presence of a catalyst. In this reaction step, the hydroxyl groups (-OH) on the anhydroglucose monomers of the cellulose chain are partially replaced by hydroxypropoxy groups (–OCH2CHOHCH3) after etherification.
Properties
Appearance
The substance is a slightly hygroscopic white or slightly yellowish or greyish powder. It is odourless and tasteless, and consists of a granular or fibrous form.
Solubility
In Water
- HPC: Soluble in water and swell, it generates a clear to opalescent, viscous colloidal solution.
- L-HPC: Soluble in water; swells in water. The solid dissolves in a solution of 10% sodium hydroxide to produce a viscous solution.
In Organic solvent
Ethanol dissolves the substance, ether does not.
CAS Number
9004-64-2
Structure
Chemical Formula
Polymers contain substituted anhydroglucose units with the general formula:
C6H7O2(OR1)(OR2)(OR3) is a chemical compound consisting of a central C6H7O2 group flanked by R1, R2, and R3 groups, where each R1, R2, and R3 may be one of the following:
- — H
- — CH2CHOHCH3
- — CH2CHO(CH2CHOHCH3)CH3
- — CH2CHO[CH2CHO(CH2CHOHCH3)CH3]CH3
What is hydroxypropyl cellulose in food?
Hydroxypropyl cellulose (HPC) is a food additive that is used to bring consistency to products like salad dressings and ice cream. It can also be used as a thickening agent.
Hydroxypropyl cellulose is an organic compound that is made from the cellulose in plants. These substances include grasses, woody plants, and cotton. Hydroxypropyl cellulose can be used as a thickener in foods, but it must be approved by the FDA before it can be added to any food product. HPC is not considered a significant source of calories or carbohydrates, so it does not have to be included on food labels
What are the use of hydroxypropyl cellulose?
Hydroxypropyl cellulose (HPC) is a water-soluble cellulose ether that is used as an emulsifier, binder and disintegrant in tablets and capsules. It is also used as a thickener, stabilizer and gelling agent in food products such as ice cream, cheese spreads and fruit fillings.
In addition to its use as a thickener, emulsifier and stabilizer in food and cosmetics, HPC is commonly used in pharmaceuticals as a disintegrant and binder for tablets.
Food
Precooked Food
HPC, which stands for high pressure processing, can preserve the freshness of hamburger, pizza, chicken and other foods. It is sprayed onto the surface of these foods before they are cooked and then rapidly disintegrates within 3 minutes during cooking.
Stabilizer
High-polymer cream (HPC) functions as an emulsifier and stabilizer in ice cream and frozen milk to prolong the storage period, improve the overflow, and prevent the formation of ice crystals. It is also used as a coating for chocolate, preventing the chocolate from softening, oxidation and mold when stored in a frozen temperature.
It can also be used to stabilize loose food products, and it is excellent at creating a thick foam. It performs excellently with vegetable oils.
Cosmetics
The European Commission database for information on cosmetic substances and ingredients lists propylene glycol (HPC) as an agent that can be used in binding, emulsifying, emulsion stabilising, film forming, and viscosity controlling applications.
Pharmaceuticals
L-HPC, (Sodium Lauryl Sulfate) is used as a disintegrant for its swelling action in water. It is also useful for both wet and dry blending in hard tablets because of it has a good ability to compress and bind.
Disintegration
L-HPC absorbs water and swells, becoming several times its original volume, although it is not suitable for use in an aqueous solution. This property accelerates the disintegration of tablets and increases their fineness.
L-HPC has a greater disintegration capability than sodium starch glycolate in both vitamin C tablets and aspirin tablets.
Compression
L-HPC is useful as a binder in both direct compression and wet granulation tablets. It increases the hardness of the tablet, making it harder than other excipients like croscarmellose sodium.
Non-ionic excipients have a low potential for drug interaction and improve the bioavailability of active ingredients in tablets. The interaction between non-ionic excipients and active ingredients is minimal, unlike ionic excipients under similar moisture levels.
Treating Dry Eyes
Hydroxypropyl cellulose has a variety of uses in prescriptions for treating dry eyes and other eye disorders, such as keratitis and decreased corneal sensitivity.
Is hydroxypropyl cellulose safe?
Yes, the safety of both high-pressure processed (HPC) and low-hydrostatic-pressure processed (L-HPC) food products has been approved by the U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA), Joint FAO/WHO Expert Committee on Food Additives (JECFA), and other regulatory agencies.
FDA
HPC and L-HPC may be used safely in food products as a emulsifier or emulsifier salt, formulation aid, stabilizer or thickener and texturizer.
EFSA
The food additive HPC (E463) and L-HPC (E 463a) are listed in Commission Regulation (EU) No 231/2012 as an authorised additive in the categories “flavour enhancers” and “aromatic substances” respectively.
HPC Safety re-evaluation in 2017
After a series of studies, EFSA concluded that “there was no need for a numerical ADI and that there would be no safety concern at the reported uses and use levels for E463.”
L-HPC Safety evaluation in 2018
The European Food Safety Authority (EFSA) concluded there would be no safety concern as a food additive in food supplements in solid form (tablet), with a maximum use level of 20,000 mg/kg and a typical use level of 10,000 mg/kg.
Uses
The specific uses of sodium carboxymethyl cellulose in food are listed in Group I and separately by E463. It is approved for use in all authorized food categories, which include Table-top sweeteners in tablets/powder form/in liquid form.
Food Standards Australia New Zealand
It is listed as an approved ingredient by the Australia and New Zealand Food Standards Code with the code number 463.
JECFA
Function: Emulsifier, glazing agent, stabilizer, thickener.
When to use hydroxypropyl cellulose?
Hydroxypropyl cellulose, also known as HPC or hydroxypropyl methyl cellulose (HPMC), is a water-soluble, viscous polymer derived from cellulose. It is used in the pharmaceutical industry to make tablets and capsules.
The use of HPC improves the dissolution rate of drugs, allowing them to be absorbed more quickly. This property makes it useful for creating enteric coatings that can resist stomach acid and dissolve only in the small intestine, where the drug will be absorbed. It can also improve the bioavailability of drugs that are poorly soluble in water by helping them dissolve faster and more completely.
Hydroxypropyl Methyl Cellulose (HPMC) is a polymer made from cellulose ethers and has similar properties as CMC in terms of solubility behavior, viscosity and stability under a wide range of conditions. The difference between these two polymers lies in their molecular structure: CMC contains hydroxyl groups on both ends while HPMC contains hydroxyls only at one end
Is hydroxypropyl cellulose safe?
Hydroxypropyl cellulose can cause allergic reactions in some people, especially when they use products containing hydroxypropyl cellulose on their face or near their eyes. The most common symptoms are redness and itching. The symptoms usually begin within 24 hours after using hydroxypropyl cellulose, but they may occur up to 72 hours later.
Hydroxypropyl cellulose has been approved by the FDA as safe for use in cosmetics and personal care products. However, if you are sensitive to hydroxypropyl cellulose, you should avoid all products containing this ingredient until your reaction has cleared up.
Is microcrystalline cellulose a preservative?
Microcrystalline cellulose is not a preservative per se, but it does help prevent spoilage. Microcrystalline cellulose prevents food from spoiling by absorbing water and oil so it doesn’t separate out of the product. It also helps form a gel or solid mass in food products that can last for years without refrigeration.
Microcrystalline cellulose is used as an emulsifier in products like ice cream, yogurt, sauces and salad dressings to keep the fat from separating out of the mixture over time. It keeps ingredients from separating when they have been cooked together at high temperatures before being cooled down again.
What is microcrystalline cellulose side effects?
Microcrystalline cellulose is a type of dietary fiber that comes from wood pulp, cotton linters and other natural sources. It’s used in foods to add bulk and texture, as well as to prevent caking.
Microcrystalline cellulose can also be added to tablets or capsules to make them easier to swallow. It’s often included in dietary supplements because it’s hypoallergenic — meaning it doesn’t contain any ingredients that could cause an allergic reaction — and it’s considered safe by the U.S. Food and Drug Administration (FDA).
The most common side effects of microcrystalline cellulose include:
Diarrhea
Gas
Indigestion
Bloating
How to manufacture hydroxypropyl cellulose?
Hydroxypropyl cellulose (HPC) is a raw material for manufacturing of various products such as cosmetics, foodstuffs and pharmaceuticals. It is also used in the medical field for the production of intravenous fluids, medication and tablets.
In this article we will discuss how to manufacture hydroxypropyl cellulose.
Manufacturing steps:
Step 1: The first step in manufacturing hydroxypropyl cellulose is to prepare the raw materials required for its production. These include purified cellulose which is obtained from wood pulp using a chemical process, sodium hydroxide (NaOH) and chloroacetic acid (CHClCOOH).
Step 2: The two chemicals are mixed together with water at a temperature of 80°C to form an emulsion. This mixture is then treated with a mechanical stirrer until it becomes stable enough to be pumped into another vessel where it solidifies into a gel-like substance known as sodium carboxymethyl cellulose or SCMC.
Step 3: The SCMC is then blended with purified water and heated at 80°C until it dissolves completely into solution. This solution contains sodium salt which is insoluble in water but soluble in alcohol . This is then transferred into another vessel where it is treated with an agitation machine to ensure that the sodium salt does not precipitate.
Step 4: After this step, the mixture is heated until a solution can be obtained. The temperature of this solution is then lowered at 0°C and stirred until it reaches room temperature.
Step 5: The mixture obtained in the previous step contains cellulose which has been dissolved in water but still remains insoluble in alcohol due to its high molecular weight. To remove this insolubility, ethanol (ethyl alcohol) and ether are added to the mixture and stirred for several hours until all of it has been completely dissolved.
Step 6: The final product obtained after manufacturing hydroxypropyl cellulose consists of hydroxypropyl methylcellulose or HPMC which contains 60% methylcelluloses content by weight. This material can be used as an ingredient for food products such as ice cream, yogurt, cheese etc.
Frequently asked questions
Is it Natural?
Synthetic compounds are not found in nature, but may be produced artificially.
Is it Halal?
Yes, It is generally considered halal, and several manufacturers have been awarded halal certification.
Is it Kosher?
Yes, This product is kosher. It has met all the “kashruth” requirements and has been certified as kosher by a rabbi.
Is it Gluten free?
Yes, The FDA states that HPC does not contain wheat, barley, or crossbreeds of these grains.
Is it Vegan?
Cellulose is a material derived from plant-based fibers, like wood chips, that can be manufactured without animal products. Therefore, it is suitable for vegetarians.
Final words:
Hydroxypropyl cellulose is a safe, tasteless and odorless substance that is widely used in food products and medications. It can be found in various forms such as tablets, capsules and fine powder. This product acts as a stabilizer for pills and capsules.
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