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Abstract
Sorbic acid (E200), chemically known as trans,trans-2,4-hexadienoic acid (CAS 110-44-1), is a widely used food preservative and antimicrobial agent.
This review comprehensively examines its chemical properties, manufacturing, applications, metabolism, safety, and regulatory status.
Sorbic acid inhibits mold, yeast, and bacterial growth primarily by disrupting intracellular pH.
Synonyms
Sorbic acid is known by various names, reflecting its chemical structure or commercial branding:,Trans,trans-2,4-hexadienoic acid,2,4-Hexadienoic acid (E,E),(E,E)-1,3-Pentadiene-1-carboxylic acid,2-Propenylacrylic acid,Panosorb,Sorbistat,Preservastat
Its low toxicity, broad spectrum of antimicrobial action, and favorable regulatory profile have established it as a preferred preservative in foods, pharmaceuticals, and cosmetics.
Ongoing research continues to evaluate its genotoxicity and exposure risks, reaffirming its safety when used within established limits.
This article synthesizes current knowledge and highlights future research directions.
Keywords
Sorbic acid, E200, food preservative, antimicrobial, CAS 110-44-1, safety, toxicity, metabolism, EFSA, FDA, regulatory status.
Introduction
Sorbic acid (E200) is a naturally occurring and industrially produced organic acid widely utilized as a preservative due to its antimicrobial properties.
Discovered in 1859, it was initially isolated from the berries of the rowan tree (Sorbus aucuparia), inspiring its name.
Its broad antimicrobial efficacy against molds, yeasts, and select bacteria under acidic conditions has made it an essential additive in food, cosmetics, and pharmaceuticals.
Given the increasing global focus on food safety and shelf-life extension, sorbic acid's role in inhibiting spoilage microorganisms while maintaining organoleptic qualities has grown considerably. Moreover, concerns regarding food additives have prompted detailed toxicological and regulatory assessments to ensure consumer safety.
This article presents an exhaustive overview of sorbic acid, including its chemistry, manufacturing processes, mechanisms of action, applications, metabolism, toxicity, and current regulatory perspectives.
Chemical Identity & Synonyms
IUPAC Name: (2E,4E)-Hexa-2,4-dienoic acid
Common Name: Sorbic acid
E-Number: E200
CAS Number: 110-44-1
Molecular Formula: C₆H₈O₂
Molecular Weight: 112.12 g/mol
These synonyms appear in scientific literature, safety data sheets, and industrial specifications, ensuring clarity across contexts.
Physicochemical Properties & Structural Data
Sorbic acid is a linear, unsaturated carboxylic acid characterized by two conjugated double bonds in the trans configuration at carbons 2 and 4.
This conjugation stabilizes the molecule and contributes to its biological activity.
Property Description
Appearance White crystalline powder/needles
Molecular Weight 112.12 g/mol
Melting Point 133–135 °C
Boiling Point 228 °C at 4 mm Hg
Density 1.279 g/cm³
pKa (acid dissociation) ≈ 4.76
Solubility in Water ~1.6 g/L at 20 °C
Solubility in Ethanol Highly soluble
Odor Mild, slightly acidic
Structural Features
The two trans double bonds provide rigidity and prevent isomerization under normal conditions.
The carboxyl group is responsible for acidity and microbial inhibition via intracellular acidification.
The lipophilic tail facilitates membrane penetration, essential for antimicrobial activity.
Manufacturing Processes & Industrial Synthesis
Natural Occurrence and Extraction
Sorbic acid occurs naturally in the berries of the rowan tree (Sorbus aucuparia).
Early isolation was achieved through extraction and crystallization from rowan berry oil, but natural extraction is limited by low yields and high cost.
Industrial Synthesis
Commercial production predominantly employs synthetic routes for high purity and cost-effectiveness:
Aldol Condensation Route: The principal method involves condensation of crotonaldehyde with ketene in the presence of catalysts such as boron trifluoride.
Steps:
Crotonaldehyde reacts with ketene under controlled temperature and pressure.
The intermediate undergoes dehydration and isomerization to form sorbic acid.
Purification is achieved via crystallization and distillation.
Yield efficiencies typically range around 70-85%. Continuous production techniques allow large-scale manufacturing to meet global demand.
Mechanisms of Antimicrobial Action & pH-Dependence
Sorbic acid’s antimicrobial efficacy is primarily linked to its ability to disrupt cellular processes in microorganisms:
Mode of Action
Sorbic acid exists mostly in the undissociated form at acidic pH (pKa 4.76).
The lipophilic undissociated acid penetrates microbial cell membranes, entering the cytoplasm.
Inside the cell, the relatively neutral pH causes dissociation, releasing protons and sorbate ions.
This acidification disrupts intracellular pH homeostasis, enzyme function, and nutrient transport.
Additionally, sorbate ions interfere with metabolic pathways and ATP synthesis.
These combined effects inhibit growth and reproduction of molds, yeasts, and some bacteria.
pH Dependence
Most effective under acidic conditions (pH < 6.5).
Above this pH, increased ionization reduces membrane permeability and efficacy declines.
This limits its use primarily to acidic or low-pH foods such as cheeses, beverages, and baked goods.
SAFETY INFORMATION ABOUT E200 SORBIC ACID
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off conSAFETYtaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
