Sodium carrageenan

Sodium carrageenan is the sodium salt of carrageenan, a family of sulfated galactans extracted from red seaweeds (notably Kappaphycus, Eucheuma, Chondrus). It functions primarily as a thickener, gelling agent, and stabilizer. Performance depends on carrageenan type—κ (kappa), ι (iota), or λ (lambda)—and on the system’s ionic balance.

Caloric value (dry product, 100 g)
Approximately 200–250 kcal per 100 g (typical ≈ 200 kcal/100 g, assuming fermentable dietary fiber at ~2 kcal/g; food-use levels are low, usually 0.05–1.0%).

Structure and types
Kappa forms strong, brittle gels promoted by monovalent cations (especially K⁺) and shows synergy with LBG.
Iota forms soft, elastic, freeze–thaw-tolerant gels promoted by divalent cations (especially Ca²⁺).
Lambda does not gel and acts as a cold-soluble thickener that stabilizes foams and emulsions.
The sodium form improves solubility and viscosity but produces weaker gels unless potassium or calcium is introduced.

Key constituents
Sulfated galactan matrix built from D-galactose and 3,6-anhydro-D-galactose units bearing sulfate groups.
Sodium ions (Na⁺) as predominant counterions; traces of K⁺/Ca²⁺/Mg²⁺ depending on processing.
Ash/sulfate within food-grade specifications; low acid-insoluble matter; controlled moisture.
High-molecular-weight fractions typical of food grades (distinct from degraded, low-molecular-weight poligeenan).
Minor residual seaweed cell-wall components (cellulose/hemicelluloses) depending on refinement level.

Production process
Seaweed sourcing (cultivated or wild) → cleaning, drying, size reduction.
Hot-water extraction (often mildly alkaline) to solubilize sulfated galactans.
Clarification/filtration to remove fibers; optional alkaline treatment to increase 3,6-anhydrogalactose (especially for κ/ι).
Precipitation (e.g., isopropanol) or gel-press with salts, followed by washing.
Conversion/standardization to the sodium form (neutralization/ion exchange), adjustment of ionic profile (K⁺/Ca²⁺) as needed.
Controlled drying, milling, and particle-size classification; optional blending of κ/ι/λ to target performance.
Quality controls: moisture, ash/sulfate, viscosity under defined conditions, κ/ι gel strength, acid-insoluble matter, microbiology.
Packaging in barrier materials with full lot traceability under GMP/HACCP and defined CCPs.

Hydration, solubility, and ionic effects
Most grades hydrate at 70–85 °C; λ-rich and some refined sodium grades can hydrate cold under sufficient shear.
Gelation is thermoreversible; set/melt temperatures depend on concentration, type (κ/ι/λ), and added salts.
Acid plus heat accelerates depolymerization; maintain pH above ~3.8 during thermal steps.
K⁺ strengthens κ-gels and reduces syneresis; Ca²⁺ strengthens ι-gels; excess Na⁺ favors viscosity over gel firmness.

Functional properties
Low-dose viscosity building with shear-thinning flow.
Protein reactivity that stabilizes dairy/cocoa beverages, limiting sedimentation and wheying-off.
Synergy with LBG (κ + locust bean gum) to enhance elasticity and reduce syneresis.
Compatibility with starches and proteins for heat-stable textures in custards, puddings, and fillings.

Food applications
Dairy and plant-based beverages (cocoa suspension, chocolate milk), cultured/processed cheeses, gel desserts, water binding in cooked meats and deli items, confectionery gels, sauces and glazes, ice cream/soft-serve stabilization, and plant-based analogs. Typical use: 0.03–0.5% in beverages; 0.2–1.0% in gels and processed meats, depending on type and ions.

Cosmetic (INCI) functions
Listed as INCI “Sodium Carrageenan.” Typical functions: viscosity-increasing agent (aqueous), film forming, emulsion stabilizing, binder, and skin/hair conditioning (sensory slip and light moisturization by water structuring).

Nutrition and health
Food-grade carrageenan (including sodium salts) is a high-molecular-weight hydrocolloid used at low levels and contributes fiber-like energy via colonic fermentation. It is distinct from degraded “poligeenan,” which is not permitted in foods. Individual tolerance varies by matrix and dose.

Quality and specification themes
Moisture typically ≤12–15%; ash/sulfate within grade spec; low acid-insoluble matter; particle size tuned for target hydration.
Microbiological criteria suitable for dry gums; contaminants within legal limits.
Functional testing: viscosity at specified shear/temperature, gel strength for κ/ι types, and clarity/color indices.
Traceability and process hygiene under GMP/HACCP with defined CCPs.

Processing and formulation guidance
Disperse into a vortex or dry-premix with other powders to avoid fisheyes; hydrate with appropriate time/temperature and shear.
Adjust pH after hydration when feasible; avoid prolonged heating at low pH.
Tune the cation profile: add KCl for κ-gels, CaCl₂ for ι-gels; blend κ with LBG for elasticity and reduced syneresis.
Limit excess sodium if a firm gel is desired; sodium favors viscosity rather than rigidity.

Troubleshooting
Weak/brittle gel: insufficient K⁺/Ca²⁺, low solids, or harsh acid/heat history → raise dose, add KCl/CaCl₂, adjust pH/thermal profile.
Phase separation in beverages: inadequate hydration or protein interaction → raise hydration temperature/time, tune pH/salt, include κ-rich grade with LBG synergy.
Lumps (“fisheyes”): poor dispersion → increase shear, dry-premix with sugar, or slurry in oil/glycerin before addition.
Grainy set or syneresis: suboptimal κ:ι:λ ratio or ionic mismatch → rebalance type blend and cation profile.

Storage and shelf life
Store cool and dry in sealed, moisture-barrier packaging; control ambient RH to prevent caking and performance loss.
Avoid strong odors and direct light; apply FIFO rotation. Properly stored powders remain functional for many months.

Sustainability and supply chain
Derived from cultivated or wild-harvested red seaweeds. Responsible aquaculture and traceable sourcing support coastal livelihoods and biodiversity. Processing facilities should manage effluents against BOD/COD targets and operate under GMP/HACCP.

Conclusion
Sodium carrageenan is a versatile hydrocolloid whose performance hinges on type selection, dispersion/hydration, pH, and ionic balance. With informed formulation—especially potassium or calcium addition and κ–LBG synergy—it delivers dependable thickening, gelling, and stabilization across beverages, gels, dairy, meat, plant-based foods, and cosmetic systems.

Mini-glossary
pH — Measure of acidity/alkalinity; low pH plus heat accelerates carrageenan depolymerization.
LBG — Locust bean gum; synergistic with κ-carrageenan to strengthen gels and reduce syneresis.
INCI — International Nomenclature of Cosmetic Ingredients; standardized naming and function mapping for cosmetic ingredients.
GMP — Good Manufacturing Practice; hygiene and process controls ensuring consistency, traceability, and quality.
HACCP — Hazard Analysis and Critical Control Points; preventive food-safety system defining hazards and controls.
CCP — Critical control point; a step where control prevents, eliminates, or reduces a food-safety hazard to acceptable levels.
RH — Relative humidity; higher RH promotes caking and reduced powder performance.
FIFO — First in, first out; inventory rotation to use older lots first.
BOD/COD — Biochemical/Chemical oxygen demand; indicators of organic load in effluents for environmental management.

Medical

Phytochemical analysis of carrageenan has shown the presence of alkaloids, saponins, steroids, gums, mucilages and carbohydrates in both native and commercial carrageenan with antioxidant activities (1).

Food

In European food additives it is labelled with the number E407 as a thickener. Used as a stabiliser, gelling agent, binder and thickener in processed meat and poultry products. It improves the freeze-thaw ratio, stability, flavour and cuttability in poultry products. 

Carrageenan has the property of maintaining the organoleptic and structural values of fat-free cheese and can replace casein in cheese imitations and stabilise the structure in cheese-like products (2).

Lightening agent in beverages. Incorporated into confectionery products such as gummy sweets, ice cream and food jelly it can replace agar, pectin and gelatine.

Safety

A rather debated ingredient in recent years by toxicology studies and chronic toxicological tests (3).

 A 2024 study warns about the risk of developing cancer with high intakes of emulsifiers, (including E440, Pectin, E471 mono- and diglycerides of fatty acids, carrageenan, E407, sodium carbonate E500) (4).  

Carrageenan studies

Typical commercial product characteristics Carrageenan

Appearance	White powder
pH	8- 11 (1% solution)
PSA	394.53000
Sulfate	15- 40%
Loss on drying	12 Max%
Viscosity (1.5%, 75°C, mPa.s )	5 min
Gel Strength (1.5% w/w, 0.2% KCl, 25°C, g/cm2)	1500 min
Transparency	75 min
Plate Count	5000cfu/g max
Total ash	15%~40%
Acid insoluble ash	1.0% Max
Acid Insoluble matter	5.0% Max
Lead	5 mg/kg Max
Arsenic	3 mg/kg Max
Mercury	1 mg/kg Max
Cadmium	1 mg/kg Max
Total Heavy Metals (as Pb)	10 mg/kg Max
Yeasts & Moulds	300 cfu/g Max
Safety

• Molecular Formula  C₂₃H₂₃Fn₄O₇Zn
• Molecular Weight   788.65
• Exact Mass    788.09900
• CAS    9000-07-1   11114-20-8
• UNII    DV181E4639
• EC Number   232-524-2
• DSSTox Substance ID  DTXSID3020255
• IUPAC  zinc;1-(5-cyanopyridin-2-yl)-3-[(1S,2S)-2-(6-fluoro-2-hydroxy-3-propanoylphenyl)cyclopropyl]urea;diacetate
• InChI=1S/C19H17FN4O3.2C2H4O2.Zn/c1-2-15(25)11-4-5-13(20)17(18(11)26)12-7-14(12)23-19(27)24-16-6-3-10(8-21)9-22-16;2*1-2(3)4;/h3-6,9,12,14,26H,2,7H2,1H3,(H2,22,23,24,27);2*1H3,(H,3,4);/q;;;+2/p-2/t12-,14+;;;/m1.../s1  
• InChl Key      UHVMMEOXYDMDKI-JKYCWFKZSA-L
• SMILES   CCC(=O)C1=C(C(=C(C=C1)F)C2CC2NC(=O)NC3=NC=C(C=C3)C#N)O.CC(=O)[O-].CC(=O)[O-].[Zn+2]
• MDL number  MFCD00081480
• PubChem Substance ID    
• FEMA   2596
• RTECS   FI0704000

Synonyms

• kappa-Carrageenan
• k-Carrageenan
• Carrageenan Kappa Refined
• Carrageenan Kappa Semi-refined

References_______________________________________________________________

(1) Suganya AM, Sanjivkumar M, Chandran MN, Palavesam A, Immanuel G. Pharmacological importance of sulphated polysaccharide carrageenan from red seaweed Kappaphycus alvarezii in comparison with commercial carrageenan. Biomed Pharmacother. 2016 Dec;84:1300-1312.

(2) Błaszak BB, Gozdecka G, Shyichuk A. Carrageenan as a functional additive in the production of cheese and cheese-like products. Acta Sci Pol Technol Aliment. 2018 Apr-Jun;17(2):107-116. doi: 10.17306/J.AFS.0550.

Abstract. Carrageenan is a well-known gelling agent used in the food industry. The present review of patent and scien- tific literature shows that carrageenan is a useful additive in the cheese production process. The gel-strength- ening properties of carrageenan are as a result of the fairly strong bonds it forms with casein macromolecules. However, carrageenan-casein interaction is dependent on pH. Different carrageenan types have different charge levels (the most charged is the helix form of lambda-carrageenan), which affects the carrageenan- casein aggregates. The correct concentration of carrageenan and temperature treatment can improve cheese yield and whey protein recovery, which is desirable for cheese producers. Even small amounts of this hydro- colloid can increase cheese firmness and maintain cheese structure after cheese curd heating. Carrageenan improves cheese structure and other properties, such as ease of grating or slicing, which are very important for customers. Some modifications to cheese composition can destroy the natural cheese structure, but the addition of carrageenan can be useful for creating modified cheese-like products with desirable attributes. Carrageenan can be a good replacement for emulsifying salts, to stabilize cheese fat without disturbing the Ca:P ratio. The replacement of emulsifying salts with carrageenan (as little as 1%) results in a homogenous cheese product. For that reason, carrageenan is a useful additive for maintaining the organoleptic and struc- tural values of fat-free cheese. Carrageenan can also stabilize the structure in cheese-like products and replace casein in cheese imitations.

(3) David S, Shani Levi C, Fahoum L, Ungar Y, Meyron-Holtz EG, Shpigelman A, Lesmes U. Revisiting the carrageenan controversy: do we really understand the digestive fate and safety of carrageenan in our foods? Food Funct. 2018 Mar 1;9(3):1344-1352. doi: 10.1039/c7fo01721a.

Abstract. Carrageenan (CGN), a family of marine polysaccharides isolated from seaweeds, has been at the heart of considerable debate in recent years. To date, CGN is generally recognized as safe based on a history of safe use, various acute toxicology studies and some recent chronic toxicology tests. This review offers readers an overview of evidence on CGN characteristics and digestive fate that highlight various gaps in our understanding. Specifically, three unresolved gaps are identified. Firstly, little information can be found on the current levels of public exposure to CGN. Secondly, the link between CGN physicochemical properties, its impact on digestive proteolysis, the colon microbiome and inflammation are yet to be fully resolved. Thirdly, scant scientific evidence exists on the differential digestive fate of CGN in the gut of liable and predisposed populations, such as elderly people or IBD patients. Altogether, revisiting the scientific evidence indicates that more research is needed to elucidate the possibility that continued exposure to increasing levels of CGN in the human diet may compromise human health and well-being.

Tobacman JK. Review of harmful gastrointestinal effects of carrageenan in animal experiments. Environ Health Perspect. 2001 Oct;109(10):983-94. doi: 10.1289/ehp.01109983.

Abstract. In this article I review the association between exposure to carrageenan and the occurrence of colonic ulcerations and gastrointestinal neoplasms in animal models. Although the International Agency for Research on Cancer in 1982 identified sufficient evidence for the carcinogenicity of degraded carrageenan in animals to regard it as posing a carcinogenic risk to humans, carrageenan is still used widely as a thickener, stabilizer, and texturizer in a variety of processed foods prevalent in the Western diet. I reviewed experimental data pertaining to carrageenan's effects with particular attention to the occurrence of ulcerations and neoplasms in association with exposure to carrageenan. In addition, I reviewed from established sources mechanisms for production of degraded carrageenan from undegraded or native carrageenan and data with regard to carrageenan intake. Review of these data demonstrated that exposure to undegraded as well as to degraded carrageenan was associated with the occurrence of intestinal ulcerations and neoplasms. This association may be attributed to contamination of undegraded carrageenan by components of low molecular weight, spontaneous metabolism of undegraded carrageenan by acid hydrolysis under conditions of normal digestion, or the interactions with intestinal bacteria. Although in 1972, the U.S. Food and Drug Administration considered restricting dietary carrageenan to an average molecular weight > 100,000, this resolution did not prevail, and no subsequent regulation has restricted use. Because of the acknowledged carcinogenic properties of degraded carrageenan in animal models and the cancer-promoting effects of undegraded carrageenan in experimental models, the widespread use of carrageenan in the Western diet should be reconsidered.

(4) Sellem, L., Srour, B., Javaux, G., Chazelas, E., Chassaing, B., Viennois, E., ... & Touvier, M. (2024). Food additive emulsifiers and cancer risk: Results from the French prospective NutriNet-Santé cohort. Plos Medicine, 21(2), e1004338.

Abstract. Emulsifiers are widely used food additives in industrially processed foods to improve texture and enhance shelf-life. Experimental research suggests deleterious effects of emulsifiers on the intestinal microbiota and the metabolome, leading to chronic inflammation and increasing susceptibility to carcinogenesis. However, human epidemiological evidence investigating their association with cancer is nonexistent. This study aimed to assess associations between food additive emulsifiers and cancer risk in a large population-based prospective cohort.