L-Cystine
Amino Acids
Nutritional Enhancers
56-89-3
C₆H₁₂N₂O₄S₂
$26.68 ~ $40.02
Food
Free sample from 100g(NF)
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Product Info
What is L-Cystine?
L-Cystine is a stable, non-essential amino acid primarily used as a nutritional supplement and as a dough conditioner in bakery goods to strengthen the gluten structure.
How is L-Cystine made?
| Step No. | Production Stage | Key Action | Control Point & Note |
|---|---|---|---|
| 1 | Raw Material Preparation | Select and clean keratin-rich raw materials, typically poultry feathers or human hair. Wash thoroughly to remove dirt and foreign matter. | Source and quality of raw material are critical for final purity. Material must be free from harmful contaminants. |
| 2 | Acid Hydrolysis | Load the cleaned material into a reactor with concentrated hydrochloric acid (HCl). Heat the mixture to break down the keratin protein into its constituent amino acids. | Crucial to control acid concentration, temperature (e.g., 105-115°C), and reaction time (e.g., 8-12 hours). Insufficient hydrolysis results in low yield, while excessive conditions can degrade the L-Cystine. |
| 3 | Neutralization & Filtration | Cool the acidic hydrolysate and neutralize it with a base (e.g., sodium hydroxide or calcium hydroxide). Filter the solution through activated carbon to decolorize it and remove insoluble impurities. | Precise pH adjustment is key to beginning the separation process. The efficiency of the filtration and decolorization steps significantly impacts the purity of the intermediate product. |
| 4 | Isolation & Crystallization | Carefully adjust the pH of the filtrate to the isoelectric point of L-Cystine (approx. 4.8). L-Cystine, being insoluble at this pH, precipitates out of the solution. Cool the solution to promote crystallization. | This is a critical precipitation step. Accurate pH control is mandatory for selective isolation. The cooling rate influences crystal size and purity. |
| 5 | Purification (Recrystallization) | Separate the crude L-Cystine crystals and re-dissolve them in a dilute acid solution. Repeat the neutralization and precipitation process (Step 4) to wash away remaining soluble impurities. | The number of recrystallization cycles depends on the required final purity. Use of purified or deionized water is essential to avoid introducing new contaminants. |
| 6 | Centrifuging & Drying | Separate the purified L-Cystine crystals from the liquid using a centrifuge. Wash the crystal cake with purified water. Dry the crystals in a vacuum dryer under controlled temperature. | Control of drying temperature and time is vital to achieve the specified moisture content without causing thermal degradation. The centrifuge must be hygienically maintained to prevent cross-contamination. |
| 7 | Milling & Sieving | Mill the dried crystals to achieve a uniform, fine powder. Sieve the powder through a specific mesh to ensure it meets particle size specifications. | The mesh size of the sieve is a key control point for ensuring final product consistency and meeting customer requirements for particle size distribution. |
| 8 | Quality Control & Packaging | Conduct final quality tests for purity (assay), heavy metals, microbial content, specific rotation, and other parameters as per pharmacopoeial standards (e.g., USP, EP). Package the final product in sealed, multi-layer bags. | Final product must conform to all specifications before release. Packaging must protect the product from moisture, light, and contamination during storage and transport. |
Technical Specifications
| CAS Number | 56-89-3 |
| Chemical Formula | C₆H₁₂N₂O₄S₂ |
| Solubility | Poorly soluble in water (~0.112 g/L at 25 °C), soluble in acid/alkali |
| Storage Conditions | Cool, dry, dark; avoid moisture and oxidation |
| Shelf Life | 24 Months |
Applications & Usage
Common Applications:
Flour treatment
nutritional supplements
pharmaceuticals
cosmetics
cell culture media
Mechanism of action:
| Parameter | L-Cystine |
|---|---|
| Functional Category | Dough Conditioner; Flour Treatment Agent; Reducing Agent |
| Key Ingredients | L-Cystine (a dimeric, sulfur-containing amino acid). Often used as its more soluble derivative, L-Cysteine hydrochloride. |
| Mechanism of Action | Functions as a reducing agent in dough systems. The L-Cysteine form cleaves disulfide bonds (S-S) within the gluten protein matrix via a sulfhydryl-disulfide interchange reaction. This breaks down the complex gluten network, reducing its elasticity and increasing its extensibility. |
| Application Effect in Product | Reduces dough mixing time and energy requirements. Improves dough machinability and handling properties (less "bucky"). Increases pan flow for more uniform loaf shape. Results in a softer crumb, finer texture, and potentially increased final product volume. |
Comparison:
| Product Name | Category/Type | Key Features | Strengths (vs peers) | Weaknesses (vs peers) | Best Use Cases | Why Choose |
|---|---|---|---|---|---|---|
| L-Cystine | Dimeric Amino Acid | A stable, oxidized dimer of two L-cysteine molecules; a key component of keratin. | More chemically stable and less prone to oxidation than L-cysteine. Directly provides a structural unit for hair and nails. | Less soluble and potentially has lower bioavailability than NAC or L-cysteine. Does not directly replenish glutathione as effectively as NAC. | Long-term structural support for hair, skin, and nails. Providing a stable form of a key keratin building block. | For a direct, stable building block to specifically strengthen keratin structures like hair and nails. |
| N-Acetylcysteine (NAC) | Amino Acid Derivative | An acetylated form of L-cysteine; a powerful antioxidant and precursor to glutathione. | Superior bioavailability; potent antioxidant and mucolytic properties; effectively increases glutathione levels. | Primarily functions as an antioxidant and detoxifier, not a direct structural component. Can have a strong sulfur odor. | Boosting antioxidant levels, supporting liver health and detoxification, promoting respiratory health by thinning mucus. | When the primary goal is potent antioxidant support, liver detoxification, or respiratory benefits, rather than structural protein synthesis. |
| L-Cysteine | Semi-Essential Amino Acid | The monomer form of L-cystine; a direct building block for proteins and glutathione. | More soluble than L-cystine; a more direct precursor for various metabolic functions beyond structure. | Less stable than L-cystine and can be easily oxidized in the digestive system before absorption. | General amino acid supplementation for protein synthesis; industrial use as a dough conditioner. | When a more soluble, fundamental form of the amino acid is desired for general metabolic roles. |
| L-Methionine | Essential Amino Acid | An essential, sulfur-containing amino acid that the body can convert into L-cysteine. | As an essential amino acid, it corrects dietary deficiencies that can limit cysteine production. Involved in many critical metabolic pathways. | It is an indirect source; conversion to cysteine requires multiple metabolic steps and cofactors. Less targeted than taking cysteine/cystine directly. | Addressing dietary insufficiencies of essential sulfur amino acids; supporting overall protein metabolism and methylation cycles. | To provide the body with the essential raw material it needs to produce its own cysteine and other sulfur compounds. |
| Biotin (Vitamin B7) | B-Vitamin | A water-soluble vitamin that acts as a coenzyme in metabolism, including the synthesis of fatty acids and amino acids. | Supports keratin infrastructure through a different metabolic pathway. Very effective for hair and nails if a deficiency exists. | Does not provide the physical building blocks for keratin. Benefits are often limited unless correcting a deficiency. | Improving hair and nail strength, especially when a biotin deficiency is suspected. Supporting overall energy metabolism. | To support the underlying enzymatic processes that build strong hair and nails, rather than supplying the structural components directly. |
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