Sodium carboxymethyl cellulose is food additive E466, and it is one of the most widely used hydrocolloids in processed food – not because it is fashionable, but because it is cheap, neutral in taste, cold-water soluble and reliable. The specification on the product page carries zero coliforms, zero E. coli and zero Salmonella, which is the food-grade pattern rather than an industrial one. This page covers what it does in food, how much is typically used, and the two conditions where it fails.
Identity and legal status
| Item |
Detail |
| Name |
Sodium carboxymethyl cellulose; cellulose gum |
| Additive number |
E466 in the EU; INS 466 in the Codex system |
| CAS |
9004-32-4 |
| Functional class |
Thickener, stabiliser, suspending agent, binder, film former |
| EU status |
Permitted under the food additives regulation; acceptable daily intake not specified, meaning it is used at the level needed for the technological function |
| US status |
GRAS for direct addition to food |
| Taste |
Essentially none, which is a large part of its appeal |
What it does in a food system
| Function |
Mechanism |
Why the formulator chooses it |
| Thickening |
Hydrated polymer chains raise the viscosity of the continuous phase |
Cheap viscosity, neutral taste, works cold |
| Suspending |
A yield stress holds particles in place when the product is at rest |
Keeps fruit pieces, cocoa or minerals from settling |
| Stabilising |
Adsorbs at interfaces and thickens the continuous phase |
Slows ice crystal growth and emulsion separation |
| Water binding |
Binds free water |
Reduces syneresis and staling; improves freeze-thaw stability |
| Film forming |
Dries to a cohesive film |
Glaze, coating and barrier functions |
| Bulking and body |
Adds mouthfeel without adding flavour |
Low-fat and sugar-reduced formulations |
Applications and typical use levels
| Food category |
What CMC does there |
Typical use level |
| Ice cream and frozen desserts |
Limits ice crystal growth, improves overrun stability and melt resistance |
Of the order of 0.1-0.5% |
| Bakery and dough |
Water binding, anti-staling, gas retention support |
Of the order of 0.1-0.3% on flour |
| Sauces, dressings and gravies |
Thickening, emulsion stability, suspension of particulates |
Of the order of 0.2-0.8% |
| Dairy – yoghurt and fermented milk |
Reduces whey separation, stabilises texture |
Of the order of 0.1-0.5% |
| Beverages and plant milks |
Suspends pulp or cocoa, stabilises protein dispersions |
Of the order of 0.05-0.3% |
| Confectionery and icings |
Controls crystallisation and body |
Recipe-dependent |
| Gluten-free baking |
Partially substitutes for gluten’s water binding and structure |
Of the order of 0.5-1.5% |
These are indicative ranges, not regulatory limits – the permitted level is the amount needed for the technological function, and the practical level is set by sensory trial.
Working with other hydrocolloids
| Partner |
Effect |
When it is worth doing |
| Xanthan gum |
Complementary rheology – xanthan brings a strong yield stress, CMC brings body and water binding |
Where suspension matters more than smoothness |
| Guar or locust bean gum |
Cost reduction and different texture |
Where a shorter, more brittle gel is acceptable |
| Pectin |
Acid-stable gelling in fruit systems |
Jams and fruit preparations where CMC alone would fail at low pH |
| Starch |
Bulking plus viscosity; CMC improves freeze-thaw stability |
Frozen and chilled products |
| Emulsifiers |
Interface stabilisation complements CMC’s continuous-phase thickening |
Dressings, ice cream, creamers |
The two conditions where it fails
| Condition |
What happens |
What to do instead |
| pH below roughly 4 |
The carboxyl groups protonate and the polymer becomes insoluble; the product loses viscosity or turns cloudy |
Use a higher-DS grade, or a non-ionic hydrocolloid such as HPMC, or pectin for gelled fruit systems |
| High calcium or divalent ion load |
Divalent cations crosslink the chains; the result is gelation, cloudiness or precipitation |
Higher DS, or a non-ionic ether; check the mineral content of the water and the dairy ingredients |
| Protein at its isoelectric point |
Electrostatic interaction between the anionic polymer and the protein can cause complexing and haze |
Adjust pH away from the isoelectric point, or use a non-ionic stabiliser |
Food-grade specification and documentation
| Item |
What a food-grade certificate should show |
| Purity |
99.5% minimum on a dry basis |
| Viscosity and DS |
Stated with the test conditions, so the grade is reproducible batch to batch |
| Heavy metals and individual elements |
Group limit plus lead, arsenic, cadmium and mercury separately |
| Microbiology |
Total count, yeast and mould, and absence of coliforms, E. coli and Salmonella – the absence tests are the part that matters for food |
| Residual salts |
Sodium chloride and sodium glycolate from the etherification, within the limits of the applicable food-chemicals monograph |
| Allergen and GMO statements |
CMC is not an allergen carrier and is not derived from genetically modified material, but the statements should be on file before labelling |
The practical advice for a food developer: fix the grade by its DS and viscosity first, then verify it in the actual recipe at the actual pH, because a CMC that thickens beautifully in water can lose most of its function in an acidic fruit base.
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