Cellulose is a polysaccharide biopolymer synthesised in the plant kingdom where it is found as a structural part in green plants within their primary cell wall. It is found in homicetes, a species of pseudo fungi and in algae. 

It is commonly used in food, pharmaceuticals, and cosmetics as a thickening agent, stabilizer, and filler. Cellulose is valued for its ability to form gels, provide texture, and stabilize emulsions, making it a versatile additive in various products.

Chemical Composition and Structure

Cellulose is a complex carbohydrate made up of glucose units linked by β-1,4-glycosidic bonds. Its linear structure forms long chains that are insoluble in water but can swell to form gels in certain conditions. This unique structure gives cellulose its rigidity and its ability to provide bulk and texture in products.

Physical Properties

It appears as a white or off-white powder or fiber. It is insoluble in water but can absorb significant amounts of water, allowing it to act as a thickening agent or stabilizer in various formulations. Cellulose is tasteless, odorless, and non-reactive, making it an ideal additive in food, pharmaceuticals, and cosmetics.

Production Process

Cellulose is extracted from plant materials such as wood or cotton. The raw plant matter undergoes mechanical and chemical processing to isolate and purify the cellulose fibers. Once extracted, the cellulose can be further processed into various forms, such as microcrystalline cellulose, to suit specific applications.

In chemistry it is obtained from wood, especially conifers, mixed with straw and other vegetable raw materials, but bacterial cellulose is most efficiently produced by the Komagataeibacter xylinus species, a Gram-negative, aerobic, non-pathogenic bacterium belonging to the acetic bacteria family.

They are obtained from cellulose:

• biofuel production
• paper
• textile fibers
• plastics
• explosives
• paints
• biomaterials

Applications

• Food Industry: Cellulose (E460) is used as a thickener, stabilizer, and bulking agent in products like sauces, dressings, and low-calorie foods. It provides texture and prevents separation of ingredients in emulsions.

• Pharmaceuticals: In the pharmaceutical industry, cellulose is used as a binder, filler, and disintegrant in tablet formulations. It helps maintain the shape of tablets and allows for controlled release of active ingredients.

• Cosmetics: In cosmetics, cellulose is used as a thickener and stabilizer in creams, lotions, and emulsions, improving the texture and consistency of the products.

INCI Functions:

Absorbent. Absorbs substances dispersed or dissolved in aqueous solutions, water/oil, oil/water.

Opacifying agent. It is useful into formulations that may be translucent or transparent to make them opaque and less permeable to light.

Bulking agent. It regulates the water content, dilutes other solids, can increase the volume of a product for better flow, acts as a buffer against organic acids, helps to keep the pH of the mixture within a certain level.

Viscosity control agent. It controls and adapts viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

In recent years particular attention has been given to cellulose nanofibers, they are renewable and environmentally friendly (1) and they are readily available in plant biomass (2). Moreover they have remarkable mechanical performances due to their high crystallinity and proportions (3).

In medicine, cellulose nanofibers have been used as a reinforcement of biomaterials in tissue engineering (4).

Medical

In medical science, cellulose nanofibres have been used as reinforcing biomaterials in tissue engineering (4).

Food

Ingredient listed in the European food additives list as E460, bulking agent, filler and stabiliser. Its dietary advantages consist of biocompatibility, the abundance of hydroxyl groups, crystalline structure, solubility and wettability. It possesses all the characteristics of an excellent dietary fibre.

Health and Safety Considerations

Safety in Use
Cellulose (E460) is considered safe for consumption and topical use. It is non-toxic, non-allergenic, and biocompatible, making it suitable for use in food, pharmaceuticals, and cosmetics. 

Allergic Reactions
Allergic reactions to cellulose are extremely rare, as it is a naturally occurring substance in plant-based foods. It is generally well-tolerated by the body and safe for use in all age groups.

Toxicity and Carcinogenicity
It has been thoroughly evaluated by food safety authorities and is recognized as a safe food additive (E460) when used within regulated limits.

Excessive intake of E460 may be associated with high risks of cardiovascular diseases (CVD) (1).

Allergic Reactions

Environmental and Safety Considerations
Cellulose is biodegradable and does not accumulate in the environment. Its production from renewable plant sources makes it environmentally sustainable. Proper disposal and use of cellulose-based products pose no significant risks to the environment.

Regulatory Status
Cellulose (E460) is approved for use as a food additive by major regulatory bodies, including the European Union and the Food and Drug Administration (FDA) in the United States. It is classified as a safe and non-reactive additive and is widely used in food, pharmaceuticals, and cosmetics.

The most relevant studies on this ingredient have been selected with a summary of their contents:

Cellulose studies

Molecular Formula: (C₆H₁₀O₅)n  C₁₂H₂₂O₁₁

Molecular Weight: 342.297 g/mol

CAS: 9004-34-6  9013-34-7  99331-82-5

EC Number: 232-674-9  618-482-1  619-425-3

MDL number MFCD00081512

Synonyms:

• Cellulose, 2-(diethylamino)ethyl ether
• (5S)-6-(hydroxymethyl)-5-{[(2S)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}oxane-2,3,4-triol
• (5S,2R,3R,4R,6R)-5-[(2S,4S,5S,3R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)(2H-3,4 ,5,6-tetrahydropyran-2-yloxy)]-6-(hydroxymethyl)-2H-3,4,5,6-tetrahydropyran-2, 3,4-triol
• (6S)-2-(hydroxymethyl)-6-[(3S)-4,5,6-trihydroxy-2-(hydroxymethyl)tetrahydropyran-3-yl]oxy-tetrahydropyran-3,4,5-triol

References_________________________________________________________________________

(1) Osorio‐Madrazo, A., & Laborie, M. P. (2013). Morphological and thermal investigations of cellulosic bionanocomposites. Biopolymer Nanocomposites: Processing, Properties, and Applications, 411-436. 

Abstract. This chapter highlights the impact of cellulose nanofibers (CNFs) on the thermal properties of polymers and provides insight into the composite morphologies down to the molecular scale. With a particular focus on semicrystalline biodegradable polymers, the chapter attempts to decipher the role of CNF surface attributes, shape, and loading amounts on morphological and thermal properties. Thus, the chapter reviews the theoretical framework of polymer transitions and crystallization kinetics for semicrystalline polymers. Finally, it discusses the morphology and thermal behavior (other than thermal stability) of specific cellulose/ biopolymer matrix materials.

(2)  Native crystalline polysaccharide nanofibers: Processing and properties.Samyn P., Osorio-Madrazo A.  Barhoum A., Bechelany M., Makhlouf A., editors. Handbook of Nanofibers. Springer; Cham, Switzerland: 2018. pp. 1–36

(3)  Favier, V., Chanzy, H., & Cavaillé, J. (1995). Polymer nanocomposites reinforced by cellulose whiskers. Macromolecules, 28(18), 6365-6367.. doi: 10.1021/ma00122a053. 

(4) Doench I, Torres-Ramos MEW, Montembault A, Nunes de Oliveira P, Halimi C, Viguier E, Heux L, Siadous R, Thiré RMSM, Osorio-Madrazo A  Injectable and Gellable Chitosan Formulations Filled with Cellulose Nanofibers for Intervertebral Disc Tissue Engineering.  Polymers (Basel). 2018 Oct 27; 10(11)

Abstract. The development of non-cellularized injectable suspensions of viscous chitosan (CHI) solutions (1.7⁻3.3% (w/w)), filled with cellulose nanofibers (CNF) (0.02⁻0.6% (w/w)) of the type nanofibrillated cellulose, was proposed for viscosupplementation of the intervertebral disc nucleus pulposus tissue. The achievement of CNF/CHI formulations which can gel in situ at the disc injection site constitutes a minimally-invasive approach to restore damaged/degenerated discs. We studied physico-chemical aspects of the sol and gel states of the CNF/CHI formulations, including the rheological behavior in relation to injectability (sol state) and fiber mechanical reinforcement (gel state). CNF-CHI interactions could be evidenced by a double flow behavior due to the relaxation of the CHI polymer chains and those interacting with the CNFs. At high shear rates resembling the injection conditions with needles commonly used in surgical treatments, both the reference CHI viscous solutions and those filled with CNFs exhibited similar rheological behavior. The neutralization of the flowing and weakly acidic CNF/CHI suspensions yielded composite hydrogels in which the nanofibers reinforced the CHI matrix. We performed evaluations in relation to the biomedical application, such as the effect of the intradiscal injection of the CNF/CHI formulation in pig and rabbit spine models on disc biomechanics. We showed that the injectable formulations became hydrogels in situ after intradiscal gelation, due to CHI neutralization occurring in contact with the body fluids. No leakage of the injectate through the injection canal was observed and the gelled formulation restored the disc height and loss of mechanical properties, which is commonly related to disc degeneration.

(5) Sellem L, Srour B, Javaux G, Chazelas E, Chassaing B, Viennois E, Debras C, Salamé C, Druesne-Pecollo N, Esseddik Y, de Edelenyi FS, Agaësse C, De Sa A, Lutchia R, Louveau E, Huybrechts I, Pierre F, Coumoul X, Fezeu LK, Julia C, Kesse-Guyot E, Allès B, Galan P, Hercberg S, Deschasaux-Tanguy M, Touvier M. Food additive emulsifiers and risk of cardiovascular disease in the NutriNet-Santé cohort: prospective cohort study. BMJ. 2023 Sep 6;382:e076058. doi: 10.1136/bmj-2023-076058. PMID: 37673430; PMCID: PMC10480690.