Quick Search
Monosodium Glutamate (MSG) is the sodium salt of glutamic acid, a naturally occurring non-essential amino acid.
It is widely used as a flavor enhancer in the food industry, imparting a rich umami (savory) taste to foods. MSG is a white crystalline powder that is odorless, soluble in water, and stable under heat.
It is commonly added to snacks, canned soups, processed meats, instant noodles, and restaurant dishes.
CAS Number: 142-47-2
Synonyms:
MSG,Sodium glutamate,Monosodium L-glutamate,Glutamic acid, monosodium salt,Ajinomoto (brand name),Flavor enhancer 621
Introduction
Monosodium glutamate (MSG), designated as food additive E621, is the sodium salt of the naturally occurring non-essential amino acid glutamic acid.
It is widely used as a flavor enhancer due to its ability to elicit the umami taste—one of the five basic tastes.
Since its discovery in 1908 by Kikunae Ikeda, MSG has become a staple ingredient in the global food industry.
MSG is synthesized through natural fermentation processes and is generally recognized as safe (GRAS) by major regulatory bodies, including the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA).
However, its use has also spurred debates regarding potential health effects, particularly related to the so-called "Chinese Restaurant Syndrome."
Chemical Structure and Properties
MSG has the chemical formula C5H8NO4Na and a molecular weight of 169.11 g/mol.
It is a white, odorless crystalline powder that is highly soluble in water.
MSG dissociates into free glutamate and sodium ions when dissolved, enhancing its interaction with taste receptors on the tongue.
Key Physical and Chemical Properties:
Melting Point: Decomposes at 232°C
Solubility: Highly soluble in water (740 g/L at 20°C)
pH of 1% solution: ~6.7–7.2
Appearance: White crystalline powder
Production Methods
Originally extracted from seaweed, MSG is now predominantly produced via bacterial fermentation. Modern methods employ strains of Corynebacterium glutamicum and other microorganisms capable of converting carbohydrates into glutamic acid, which is subsequently neutralized with sodium to form MSG.
Production Steps:
Fermentation: Carbohydrates (e.g., sugar beets, molasses) are fermented by bacteria.
Recovery: The fermentation broth is filtered to extract glutamic acid.
Neutralization: Glutamic acid is reacted with sodium hydroxide.
Crystallization: MSG is crystallized, dried, and packaged.
Applications
MSG is primarily used in the food industry to enhance savory flavors in processed foods, soups, snacks, canned vegetables, and meats.
It is also employed in:
Pharmaceuticals: As a stabilizer in certain medications.
Cosmetics: As a pH regulator and skin conditioning agent.
Animal Feed: To increase palatability.
Mechanism of Action
MSG enhances flavor through activation of the umami receptors on the tongue, specifically the metabotropic glutamate receptor mGluR4 and the heterodimer T1R1/T1R3.
These receptors signal to the brain that the food contains proteins, enhancing its palatability and appeal.
Metabolism and Biokinetics
MSG is rapidly absorbed in the small intestine and metabolized in the liver. The body does not distinguish between naturally occurring glutamate in foods and glutamate from MSG.Metabolic Pathway:
Absorption in the small intestine
Transported to the liver via the portal vein
Converted into α-ketoglutarate and used in the Krebs cycle
Health Effects and Controversies
Despite its GRAS status, MSG has faced scrutiny. Critics have linked it to:
Neurological disorders: Concerns about neuroexcitotoxicity at high doses
Obesity: Debated links to increased appetite and weight gain
Headaches and allergies: Mostly anecdotal and unproven under controlled conditions
Recent meta-analyses suggest that MSG consumption within normal dietary limits is unlikely to cause adverse health effects in the general population.
Nutritional Aspects
MSG allows for flavor enhancement without excessive salt, making it useful in low-sodium diets.
It contains about one-third the sodium of table salt and can help reduce overall sodium intake without compromising taste.
Additionally, as a derivative of glutamic acid, MSG may contribute minimally to amino acid intake but is not a significant protein source.
Analytical Detection Methods
Detection and quantification of MSG in foods are important for regulatory and quality control purposes. Common methods include:
High-performance liquid chromatography (HPLC)
Ion-exchange chromatography
Enzymatic assays
Spectrophotometric methods
These methods provide accurate and reproducible measurements of MSG concentrations in complex food matrices.
Global Regulations and Labeling
MSG is regulated and approved for use in over 100 countries. Labeling requirements vary:
EU: Listed as E621; must be declared in the ingredients
US: Must appear as "Monosodium Glutamate"
Asia: Widely accepted and integrated into traditional cooking
Restrictions may apply in organic and natural food categories.
Consumer Perception and Public Opinion
Public opinion on MSG is polarized. While scientific consensus supports its safety, many consumers remain skeptical due to past media coverage and misinformation.
Education and transparent labeling are key to addressing misconceptions.
Surveys show greater acceptance in Asia compared to Western countries, where "MSG-free" labeling remains a popular marketing tactic.
Environmental Impact
MSG production via fermentation is relatively eco-friendly. However, the environmental burden includes:
Energy and water consumption
Generation of fermentation byproducts
Waste management from production facilities
Sustainable practices and waste recycling are increasingly adopted in modern production.
Alternatives and Substitutes
Several alternatives to MSG exist, including:
Yeast extracts (e.g., autolyzed yeast)
Hydrolyzed vegetable proteins
Nucleotides (IMP and GMP)
Seaweed extracts
These offer similar umami effects but may vary in flavor profile and cost.
Future Prospects and Innovations
Future developments in MSG use and production include:
Biotechnology: Genetically engineered microbes for higher yields
Encapsulation: Improved flavor delivery and controlled release
Functional foods: Combining MSG with health-promoting ingredients
Artificial intelligence: Optimizing MSG formulations in food design
As the demand for savory flavors grows globally, MSG and its alternatives will continue to evolve in both application and perception.
SAFETY INFORMATION ABOUT E 621 MONO SODIUM GLUTAMATE
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 contaminated 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
