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Send EmailCysteine Hydrochloride, L-Cysteine Hydrochloride, Cysteine HCl, E920, E921, 52-89-1, 7048-04-6
L-CYSTEINE HYDROCHLORIDE
PRODUCT IDENTIFIER INFORMATION
| Parameter | Information |
|---|---|
| Product Name | L-Cysteine Hydrochloride |
| Chemical Name (IUPAC) | (2R)-2-Amino-3-sulfanylpropanoic acid hydrochloride |
| CAS Number | 52-89-1 (Anhydrous) / 7048-04-6 (Monohydrate) |
| EC Number (EINECS) | 200-157-7 |
| Food Additive Codes | E920 (Anhydrous/L-Cysteine), E921 (Monohydrate) |
| Molecular Formula | C3H8ClNO2S (Anhydrous) / C3H8ClNO2S·H2O (Monohydrate) |
| Molecular Weight | 157.62 g/mol (Anhydrous) / 175.63 g/mol (Monohydrate) |
SECTION 1: CHEMICAL IDENTITY AND DESCRIPTION
| Parameter | Information |
|---|---|
| Chemical Name (IUPAC) | (2R)-2-Amino-3-sulfanylpropanoic acid hydrochloride |
| Systematic Name | (R)-2-Amino-3-mercaptopropionic acid hydrochloride |
| Synonyms | L-Cysteine Hydrochloride, Cysteine Hydrochloride, Cysteine HCl, L-Cysteine HCl, Cysteine Monohydrochloride, L-Cysteine Hydrochloride Monohydrate |
| Abbreviations | Cys, C, L-Cys-OH·HCl |
| CAS Number (Anhydrous) | 52-89-1 |
| CAS Number (Monohydrate) | 7048-04-6 |
| EC Number (EINECS) | 200-157-7 |
| Food Additive Codes | E920 (Anhydrous/L-Cysteine), E921 (L-Cysteine Hydrochloride Monohydrate) |
| Molecular Formula (Anhydrous) | C3H8ClNO2S |
| Molecular Formula (Monohydrate) | C3H8ClNO2S·H2O |
| Molecular Weight (Anhydrous) | 157.62 g/mol |
| Molecular Weight (Monohydrate) | 175.63 g/mol |
| Chemical Class | Amino acid hydrochloride salt (sulfur-containing amino acid) |
| Functional Groups | Amino (-NH2), carboxyl (-COOH), thiol/sulfhydryl (-SH) |
| Physical State (20°C) | Solid (white or colorless crystalline powder) |
| Odor | Odorless or very slight characteristic odor |
| Taste | Slightly acidic |
SECTION 2: PHYSICAL AND CHEMICAL PROPERTIES
| Property | Value | Test Method |
|---|---|---|
| Appearance | White or colorless crystalline powder | Visual |
| Odor | Odorless or very slight characteristic | Olfactometric |
| Taste | Slightly acidic | Sensory |
| Molecular Weight (Anhydrous) | 157.62 g/mol | Calculated |
| Molecular Weight (Monohydrate) | 175.63 g/mol | Calculated |
| Melting/Decomposition Point | >260°C (decomposes) | DSC |
| Solubility in Water (25°C) | ~28 g/100 mL (high solubility) | Gravimetric |
| Solubility in Ethanol | Slightly soluble | General Method |
| Solubility in Ether | Insoluble | General Method |
| Solubility in Acetone | Insoluble | General Method |
| pH (1% solution, 25°C) | 1.5 – 2.5 (acidic) | pH Meter |
| Specific Optical Rotation ([α]D20) | +5.0° to +8.0° (c=5, 1M HCl) | Polarimetry |
| Hygroscopicity | Moderately hygroscopic | Visual |
| Stability (Acidic pH) | Stable | Visual |
| Stability (Neutral/Alkaline pH) | Oxidizes to L-Cystine | Visual |
| Flash Point | Non-flammable | Not applicable |
SECTION 3: CHEMICAL PROPERTIES AND REACTIVITY
| Parameter | Information |
|---|---|
| Chemical Character | Acidic amino acid salt; reducing agent |
| Stability | Stable in acidic environment; oxidizes to L-Cystine (dimer) upon contact with atmospheric oxygen in neutral/alkaline environment |
| Oxidation Reaction | 2 L-Cysteine → L-Cystine + 2H+ + 2e- (disulfide bond formation) |
| Thiol Group (-SH) Reactivity | Forms complexes with metal ions; reduces disulfide bonds |
| Incompatible Materials | Strong oxidizing agents, heavy metal ions (Cu2+, Fe3+), nitrites |
| Degradation at Neutral/Alkaline pH | Oxidized by atmospheric oxygen forming low-solubility L-Cystine precipitate |
| Thermal Decomposition | >260°C: decomposition products (CO, CO2, NOx, SOx, HCl) |
| Hazardous Polymerization | Does not occur |
SECTION 4: PRODUCTION METHODS
| Method | Description | Source |
|---|---|---|
| Fermentation (Modern - Current Standard) | Specially selected bacteria or yeasts (E. coli, Candida species) synthesize L-Cysteine using plant-derived raw materials such as sugar (glucose); after purification, reacted with HCl to convert to HCl salt | Plant-derived sugars |
| Electrolytic Reduction | L-Cystine (dimer) is reduced via electrolysis to obtain L-Cysteine | L-Cystine |
| Keratin Hydrolysis (Traditional - Largely Abandoned) | Acid or enzymatic hydrolysis of keratin-rich natural sources such as human hair, pig bristles, or animal feathers | Animal/human keratin |
SECTION 5: CYSTEINE/CYSTINE FORMS COMPARISON
| Property | L-Cysteine HCl (Anhyd.) | L-Cysteine HCl Monohydrate | L-Cysteine (Free Base) | N-Acetyl-L-Cysteine (NAC) | L-Cystine |
|---|---|---|---|---|---|
| CAS Number | 52-89-1 | 7048-04-6 | 52-90-4 | 616-91-1 | 56-89-3 |
| Molecular Formula | C3H8ClNO2S | C3H8ClNO2S·H2O | C3H7NO2S | C5H9NO3S | C6H12N2O4S2 |
| Molecular Weight | 157.62 | 175.63 | 121.16 | 163.19 | 240.30 |
| Solubility in Water | ~28 g/100mL | ~28 g/100mL | ~28 g/100mL | ~10 g/100mL | ~0.01 g/100mL |
| pH (1% solution) | 1.5-2.5 | 1.5-2.5 | 4.5-5.5 | 2.0-3.0 | Neutral (insoluble) |
| Stability | Stable at acidic pH | Stable at acidic pH | Oxidizes in air | Stable | Very stable |
| Food Additive Code | E920 | E921 | E920 | - | - |
| Primary Use | Dough conditioner, antioxidant, supplement | Dough conditioner, supplement | Supplement, cosmetics | Mucolytic, antioxidant, supplement | Nutritional supplement, cell culture |
SECTION 6: FUNCTIONAL PROPERTIES AND MECHANISM OF ACTION
| Property | Description |
|---|---|
| Dough Conditioner (Flour Treatment Agent) | Breaks disulfide bonds (S-S) in gluten network, reducing dough elasticity; provides softer, more workable dough |
| Reducing Agent | Reduces disulfide bonds via thiol group (-SH); modifies protein structure |
| Antioxidant | Neutralizes free radicals; precursor in glutathione synthesis |
| Glutathione Precursor | Rate-limiting raw material in the synthesis of glutathione, one of the body's most powerful antioxidants |
| Mucolytic (in NAC form) | Breaks disulfide bonds in respiratory tract mucus, reducing sputum viscosity |
| Chelating Agent | Thiol group forms complexes with heavy metal ions; aids in detoxification |
| Collagen Synthesis | Building block in the production of collagen, essential for skin elasticity and firmness |
| Anaerobic Environment Creator | Consumes oxygen creating anaerobic conditions; provides suitable environment for probiotic development |
SECTION 7: PRIMARY APPLICATION AREAS
| Sector | Application | Typical Usage Rate |
|---|---|---|
| Food - Bakery Products | Dough conditioner (biscuits, crackers, pizza dough) | 0.003-0.01% of flour |
| Food - Meat Products | Flavor enhancer, anaerobic environment creator | 0.01-0.1% |
| Food - Antioxidant | Prevention of fruit/vegetable browning | 0.01-0.05% |
| Cosmetic - Hair Care | Active ingredient in cold wave/permanent wave solutions | 2-8% |
| Cosmetic - Skincare | Anti-aging creams, collagen support | 0.1-2.0% |
| Pharmaceutical - Mucolytic | Expectorant in NAC form (cough syrups, inhalers) | 200-600 mg/dose |
| Pharmaceutical - Supplement | Sports nutrition, protein powders, amino acid supplements | 500-1500 mg/day |
| Pharmaceutical - Detoxification | Heavy metal and toxin elimination support | 500-2000 mg/day |
| Pharmaceutical - Glutathione Support | Antioxidant protection, immune support | 500-1500 mg/day |
| Biotechnology | Essential amino acid in cell culture media | Variable |
SECTION 8: QUALITY SPECIFICATIONS (FOOD/PHARMACEUTICAL GRADE)
| Parameter | Specification | Test Method |
|---|---|---|
| Appearance | White or colorless crystalline powder | Visual |
| Odor | Odorless or very slight characteristic | Olfactometric |
| Purity (C3H8ClNO2S, Dry Basis) | 98.5 – 101.5% | HPLC / Titrimetric |
| Loss on Drying (105°C, 3 hours) | ≤ 0.5% (anhydrous); 8.0-12.0% (monohydrate) | Gravimetric |
| pH (1% solution, 25°C) | 1.5 – 2.5 | pH Meter |
| Specific Optical Rotation ([α]D20) | +5.0° to +8.0° (c=5, 1M HCl) | Polarimetry |
| Water Insoluble Matter | ≤ 0.05% | Gravimetric |
| Chloride (Cl-) | 19.8 – 22.5% (theoretical: ~22.5% anhydrous) | Argentometric |
| Sulfate (SO4 2-) | ≤ 0.03% | Turbidimetric |
| Iron (Fe) | ≤ 30 ppm | AAS / Colorimetric |
| Heavy Metals (as Pb) | ≤ 15 ppm | ICP-MS / USP <231> |
| Lead (Pb) | ≤ 3 ppm | ICP-MS |
| Arsenic (As) | ≤ 3 ppm | ICP-MS |
| Mercury (Hg) | ≤ 1 ppm | ICP-MS |
| Cadmium (Cd) | ≤ 1 ppm | ICP-MS |
| Ammonium (NH4+) | ≤ 0.03% | Ion Selective Electrode |
| Ninhydrin-Positive Substances | Passes test | TLC / HPLC |
| Total Microbial Count | ≤ 1,000 CFU/g | USP <61> |
| Yeast and Mold | ≤ 100 CFU/g | USP <61> |
| E. coli | Negative in 10g | USP <62> |
| Salmonella spp. | Negative in 25g | USP <62> |
SECTION 9: TOXICOLOGICAL PROFILE
| Parameter | Value |
|---|---|
| Acute Oral Toxicity (LD50, Rat) | > 5,000 mg/kg (low toxicity) |
| Acute Dermal Toxicity (LD50, Rabbit) | > 2,000 mg/kg |
| Skin Irritation | Irritant (due to acidic nature) |
| Eye Irritation | Severe irritant (due to acidic nature) |
| Respiratory Irritation | Inhalation of dust may cause mechanical irritation |
| Skin Sensitization | Not sensitizing |
| Carcinogenicity | Not classified (IARC, NTP) |
| Mutagenicity | Negative in in vitro tests |
| Reproductive Toxicity | No known adverse effects |
| Chronic Toxicity | Gastrointestinal discomfort at high doses |
| GRAS Status | Recognized as GRAS by FDA |
| ADI (Acceptable Daily Intake) | Not limited (JECFA) |
SECTION 10: GHS CLASSIFICATION AND LABELING
GHS Classification (compliant with 1272/2008/EC):
| Hazard Class | Category | H-Statement |
|---|---|---|
| Skin Irritation | Category 2 | H315 |
| Serious Eye Damage/Irritation | Category 2 | H319 |
| Specific Target Organ Toxicity (STOT - SE) | Category 3 | H335 |
Signal Word: WARNING
Hazard Pictograms: GHS07 (Exclamation Mark)
Hazard Statements (H-Codes):
| Code | Statement |
|---|---|
| H315 | Causes skin irritation |
| H319 | Causes serious eye irritation |
| H335 | May cause respiratory irritation |
Precautionary Statements (P-Codes):
| Code | Statement |
|---|---|
| P261 | Avoid breathing dust |
| P264 | Wash hands thoroughly after handling |
| P280 | Wear protective gloves/eye protection/face protection |
| P302+P352 | IF ON SKIN: Wash with plenty of water and soap |
| P305+P351+P338 | IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing |
| P312 | Call a POISON CENTER/doctor if you feel unwell |
SECTION 11: FIRST AID MEASURES
| Exposure Route | Action to Take |
|---|---|
| Inhalation | Move to fresh air. Seek medical attention if respiratory irritation persists. |
| Skin Contact | Wash with plenty of water and soap for at least 15 minutes. Seek medical attention if irritation persists. |
| Eye Contact | Rinse immediately with plenty of water for at least 15 minutes. Remove contact lenses if present. Seek medical attention. |
| Ingestion | Rinse mouth with water. Drink plenty of water. Seek medical attention if you feel unwell. |
SECTION 12: FIREFIGHTING MEASURES
| Parameter | Information |
|---|---|
| Fire Hazard | Non-flammable |
| Hazards During Fire | Releases CO, CO2, NOx, SOx, HCl when heated or burned |
| Suitable Extinguishing Media | Any extinguishing media appropriate for surrounding fire (water, CO2, dry chemical powder, foam) |
| Special Protective Equipment | Self-contained breathing apparatus (SCBA), full protective clothing |
SECTION 13: STORAGE AND SHELF LIFE
| Parameter | Information |
|---|---|
| Storage Conditions | Cool (15-25°C), dry, well-ventilated area; light-protective packaging |
| Container Requirements | Tightly closed, moisture-proof containers (hygroscopic) |
| Critical Separation | Strong oxidizing agents, heavy metal ions, nitrites |
| Keep Away From | Moisture (hygroscopic), direct sunlight, neutral/alkaline environments |
| Shelf Life | 24 months (unopened original packaging under appropriate storage conditions) |
| Stability Note | Stable at acidic pH; oxidizes at neutral/alkaline pH; hygroscopic |
SECTION 14: PACKAGING OPTIONS
| Packaging Type | Quantity | Material |
|---|---|---|
| Aluminum foil pouch (moisture-proof) | 1 kg | Laminated aluminum |
| Aluminum foil pouch (moisture-proof) | 5 kg | Laminated aluminum |
| Kraft bag with PE inner liner | 25 kg | Kraft paper + PE |
| PP woven bag with PE inner liner | 25 kg | PP woven + PE |
| Fiber drum | 25-50 kg | Fiberboard + PE |
SECTION 15: TRANSPORTATION INFORMATION
| Parameter | Information |
|---|---|
| UN Number | Not regulated (not hazardous) |
| Hazard Class | Not applicable |
| Packing Group | Not applicable |
| ADR/RID | Not regulated |
| IMDG Code | Not regulated |
| IATA (Air) | Not regulated |
| Marine Pollutant | No |
| Transport Temperature | Ambient (15-25°C); protect from moisture |
SECTION 16: ACCIDENTAL RELEASE AND CLEANUP
| Parameter | Information |
|---|---|
| Personal Protection | Nitrile gloves, safety goggles, dust mask (N95) |
| Cleanup Methods | Sweep up or vacuum dry. Collect in closed, labeled containers. |
| Environmental Precautions | Prevent entry of large quantities into water sources. |
| Waste Disposal | According to local regulations; dispose at licensed disposal facility. |
SECTION 17: REGULATORY STATUS
| Region / Authority | Status |
|---|---|
| European Union | Food additive E920/E921; approved as flour treatment agent (EC 1333/2008) |
| USA (FDA) | GRAS; approved as flour treatment agent and dietary supplement (21 CFR 184.1271) |
| USP-NF | Official monograph (USP L-Cysteine Hydrochloride) |
| European Pharmacopoeia | Official monograph (Ph. Eur. Cysteine Hydrochloride Monohydrate) |
| JECFA (FAO/WHO) | ADI not limited |
| Turkey | Approved under Turkish Food Codex Regulation on Food Additives |
| Halal | Available (for fermentation-derived products) |
| Kosher | Available (for fermentation-derived products) |
| Vegetarian/Vegan | Fermentation-derived products suitable; animal-derived products not suitable |
SECTION 18: OTHER NAMES AND SYNONYMS
| Type | Name |
|---|---|
| Common Names | L-Cysteine Hydrochloride, Cysteine Hydrochloride, Cysteine HCl, L-Cysteine HCl, Cysteine Monohydrochloride |
| Chemical Names (IUPAC) | (2R)-2-Amino-3-sulfanylpropanoic acid hydrochloride; (R)-2-Amino-3-mercaptopropionic acid hydrochloride |
| Abbreviations | Cys, C, L-Cys-OH·HCl |
| Food Additive Codes | E920 (Anhydrous/L-Cysteine), E921 (Monohydrate) |
| CAS Number (Anhydrous) | 52-89-1 |
| CAS Number (Monohydrate) | 7048-04-6 |
| EC Number | 200-157-7 |
SECTION 19: CYSTEINE/CYSTINE FORMS SUMMARY TABLE
| Parameter | L-Cysteine HCl Anhyd. | L-Cysteine HCl Monohyd. | L-Cysteine Free Base | N-Acetyl-L-Cysteine (NAC) | L-Cystine |
|---|---|---|---|---|---|
| CAS | 52-89-1 | 7048-04-6 | 52-90-4 | 616-91-1 | 56-89-3 |
| Molecular Weight | 157.62 | 175.63 | 121.16 | 163.19 | 240.30 |
| Water Solubility | ~28 g/100mL | ~28 g/100mL | ~28 g/100mL | ~10 g/100mL | ~0.01 g/100mL |
| pH (1% solution) | 1.5-2.5 | 1.5-2.5 | 4.5-5.5 | 2.0-3.0 | Neutral |
| Stability | Stable at acidic pH | Stable at acidic pH | Oxidizes in air | Stable | Very stable |
| E Code | E920 | E921 | E920 | - | - |
| Primary Use | Dough conditioner | Dough conditioner | Supplement | Mucolytic | Cell culture |
SECTION 20: SUMMARY TABLE
| Parameter | Value |
|---|---|
| Product | L-Cysteine Hydrochloride |
| CAS Number | 52-89-1 (Anhydrous) / 7048-04-6 (Monohydrate) |
| Food Additive Codes | E920, E921 |
| Molecular Formula | C3H8ClNO2S |
| Molecular Weight | 157.62 g/mol (Anhydrous) |
| Appearance | White crystalline powder |
| pH (1% solution) | 1.5 – 2.5 |
| Solubility in Water (25°C) | ~28 g/100 mL |
| Primary Function | Dough conditioner, reducing agent, antioxidant, glutathione precursor |
| Shelf Life | 24 months |
| GHS Signal Word | Warning |
SECTION 21: CRITICAL WARNINGS AND BEST PRACTICES
CRITICAL SAFETY WARNINGS:
-
Acidic Nature: pH 1.5-2.5; irritant to skin and eyes. Use protective equipment.
-
Oxidation Sensitivity: Rapidly oxidizes to low-solubility L-Cystine upon contact with atmospheric oxygen at neutral or alkaline pH. Store and use in acidic environment.
-
Hygroscopic: Absorbs moisture; store in airtight containers in a dry environment.
-
Reaction with Metal Ions: Forms complexes with heavy metal ions (Cu2+, Fe3+); do not store in metal containers.
-
Incompatibility with Oxidizers: Avoid contact with strong oxidizing agents.
BEST PRACTICE RECOMMENDATIONS:
-
Moisture Control: Maintain relative humidity below 50% in storage area; store with desiccants such as silica gel.
-
Acidic Solution Preparation: Prepare solutions at slightly acidic pH (pH 3-5); add citric acid or HCl for stability.
-
Flour Treatment: Typical dosage as dough conditioner is 0.003-0.01% of flour; overdosing causes excessive dough softening.
-
Halal/Kosher Verification: Prefer fermentation-derived products; request production method and certificate from supplier.
-
Light Protection: Store in light-protective packaging; UV light may accelerate oxidation.
LEGAL DISCLAIMER:
The information provided in this document is presented in good faith based on our current knowledge and experience; however, since all usage conditions are beyond our control, it does not constitute a binding specification or warranty. This Technical Data Sheet is for informational purposes only and does not constitute medical advice. Users are obligated to test the suitability for their own applications. For complete safety, storage, handling, transportation, disposal, and regulatory compliance information, refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. This product is not intended to diagnose, treat, cure, or prevent any disease.
