L-Cysteine
Amino Acids
Nutritional Enhancers
Flavoring Agents
52-90-4
E920
C₃H₇NO₂S
$7.02 ~ $10.53
Food
Free sample from 100g(NF)
One unit of:Unknown
One unit of:Unknown
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Product Info
What is L-Cysteine?
L-Cysteine is a sulfur-containing amino acid utilized as a flour treatment agent and dough conditioner in baking to reduce mixing time, and as a precursor for savory and meaty flavors.
How is L-Cysteine made?
| Step No. | Production Stage | Key Action | Control Point & Note |
|---|---|---|---|
| 1 | Seed Culture Development | A pure, high-yield strain of a microorganism (e.g., a non-pathogenic strain of E. coli or Corynebacterium glutamicum) is cultivated in a sterile lab medium. | Control Point: Strain purity and viability are paramount. The process must be strictly aseptic to prevent contamination by other microbes. |
| 2 | Fermentation | The seed culture is transferred to a large, sterile fermenter containing a nutrient-rich medium (e.g., glucose, nitrogen sources, minerals). The microorganisms multiply and secrete L-Cysteine. | Control Point: Critical parameters like temperature, pH, dissolved oxygen, and nutrient feed rate must be continuously monitored and controlled to maximize yield. |
| 3 | Cell Separation | Once the fermentation is complete, the microbial cells are separated from the fermentation broth, which now contains the dissolved L-Cysteine. | Control Point: Methods like centrifugation or microfiltration are used. The goal is to achieve a clear, cell-free broth to simplify the subsequent purification steps. |
| 4 | Purification (Ion Exchange) | The clarified broth is passed through an ion-exchange chromatography column. L-Cysteine binds to the resin in the column, while most impurities pass through. | Control Point: The pH of the broth and the type of resin are critical for selective binding. The captured L-Cysteine is later released (eluted) with a different buffer solution. |
| 5 | Crystallization | The purified L-Cysteine solution is concentrated, and crystallization is induced by carefully adjusting the pH and/or temperature. | Control Point: The rate of cooling and pH adjustment controls the crystal size and purity. This is a crucial step for removing remaining soluble impurities. |
| 6 | Crystal Separation & Washing | The solid L-Cysteine crystals are separated from the liquid (mother liquor) using centrifugation and then washed with purified water. | Control Point: Washing must be sufficient to remove surface impurities without significantly re-dissolving the product. Purity of the wash water is essential. |
| 7 | Drying | The washed, wet crystals are dried under controlled conditions to remove residual moisture and achieve the final product specification. | Control Point: Vacuum drying at a low temperature is often used to prevent thermal degradation of the amino acid. The final moisture content is a key quality attribute. |
| 8 | Sieving & Packaging | The dried L-Cysteine powder is sieved to ensure a uniform particle size and then packaged into sealed, airtight, food-grade or pharma-grade containers. | Control Point: Packaging is performed in a controlled, low-humidity environment to prevent contamination and moisture absorption. Package seal integrity is verified. |
Technical Specifications
| CAS Number | 52-90-4 |
| Chemical Formula | C₃H₇NO₂S |
| Solubility | Soluble in water (~277 g/L at 25 °C); soluble in ethanol, acetic acid, ammonia; insoluble in nonpolar solvents |
| Storage Conditions | Cool, dry, under nitrogen to avoid oxidation, avoid light |
| Shelf Life | 24 Months |
Applications & Usage
Common Applications:
Flour treatment
food flavor precursor (Maillard)
dietary supplements
pharmaceuticals
cosmetics
biochemical research
Mechanism of action:
| Parameter | L-Cysteine |
|---|---|
| Functional Category | Dough Conditioner; Reducing Agent; Flavor Precursor |
| Key Ingredients | L-Cysteine (often as L-Cysteine Hydrochloride for stability) |
| Mechanism of Action | Acts as a reducing agent via its thiol group (-SH), which cleaves disulfide bonds (-S-S-) within the gluten protein network through thiol-disulfide interchange reactions. This depolymerizes gluten proteins, reducing their molecular weight and disrupting the continuous matrix. Also serves as a sulfur-containing precursor for Maillard reaction flavor development. |
| Application Effect in Product | Reduces dough mixing time and energy requirements; improves dough extensibility and machinability, preventing tearing; increases pan flow for more uniform baked goods; creates a softer, more pliable crumb texture; generates characteristic savory/meaty flavor profiles in processed foods and seasonings. |
Comparison:
| Product Name | Category/Type | Key Features | Strengths (vs peers) | Weaknesses (vs peers) | Best Use Cases | Why Choose |
|---|---|---|---|---|---|---|
| L-Cysteine | Semi-essential amino acid | Direct precursor to glutathione; component of keratin and other proteins; food additive (E920). | Provides the amino acid in its direct form for protein synthesis. | Less stable and generally less effective for raising glutathione levels than NAC; can be rapidly oxidized. | Direct supplementation for protein structure (hair, skin); food industry applications as a dough conditioner. | When the goal is to supplement the cysteine amino acid directly for its structural role in proteins. |
| N-Acetylcysteine (NAC) | Amino acid derivative | Acetylated, more stable form of cysteine; powerful mucolytic; potent glutathione precursor. | Superior bioavailability and stability for increasing intracellular glutathione levels; extensive clinical research. | Must be converted by the body to L-cysteine; not used directly in protein synthesis. Strong sulfur odor. | Boosting glutathione, antioxidant support, respiratory health (thinning mucus), liver protection. | For the most reliable and effective oral supplementation to increase the body's master antioxidant, glutathione. |
| L-Glutathione (Reduced) | Tripeptide antioxidant | The body's "master antioxidant" in its complete form (cysteine, glycine, glutamic acid). | Supplies the final antioxidant molecule directly, bypassing the need for synthesis from precursors. | Very poor oral bioavailability; mostly broken down by digestion before it can be absorbed intact. | Use in forms that bypass digestion, such as liposomal, sublingual, or intravenous applications. | To attempt direct supplementation of the antioxidant molecule itself, ideally using an enhanced delivery system. |
| L-Methionine | Essential amino acid | Metabolic precursor to SAM-e and L-Cysteine; essential for protein synthesis. | Provides the essential building block for the entire sulfur-amino acid pathway. | Indirect and multi-step conversion to cysteine; can raise homocysteine levels if cofactors (B vitamins) are low. | Correcting a dietary deficiency of this essential amino acid; foundational support for sulfur metabolism. | To supply the ultimate starting material the body requires to produce its own cysteine and related compounds. |
| SAM-e (S-Adenosyl-L-methionine) | Metabolite / Methyl donor | Synthesized from methionine; key role in methylation, joint health, and neurotransmitter synthesis. | Provides broad metabolic support beyond just cysteine production, particularly for mood and liver function. | Significantly more expensive than other precursors; can be unstable if not properly packaged. | Supporting positive mood, promoting liver health (especially cholestasis), and maintaining joint comfort. | For targeted support of mood, liver, or joints, where its role as a universal methyl donor is paramount. |
Technical Documents
Available Documentation
COA, MSDS, technical dossier
Safety Data Sheet (SDS)
Provided
Certificate of Analysis (COA)
Quality assurance documentation
Technical Data Sheet
Detailed technical specifications