1. Basic Product Profile

• Full IUPAC Name: (2S)-2-hydroxybutanedioic acid
• Aliases: L-Malic acid, L-2-Hydroxysuccinic acid, Apple acid
• CAS Number: 97-67-6
• EINECS: 202-601-5
• Molecular Formula: C4H6O5
• Molecular Weight: 134.09
• Chemical Classification: Natural chiral dicarboxylic acid, food acidulant, nutritional supplement, pharmaceutical excipient, cosmetic pH regulator
• Core Advantages
  Natural L-configured hydroxyl dicarboxylic acid extracted from fruit fermentation, mild smooth sour taste superior to citric acid. Has dual carboxyl groups and chiral hydroxyl group, excellent buffering, flavor-enhancing and anti-oxidation performance. Widely applied in food acidity adjustment, sports energy supplements, oral pharmaceutical formulations, skincare humectant and flavor stabilizer. High biodegradability, low irritation, stable crystal form for long-term storage.

2. Physical & Chemical Properties

2.1 Physical Index

1. Appearance: White crystalline powder or granular crystal
2. Odor: Odorless, characteristic soft fruit sour taste
3. Solubility: Freely soluble in water; soluble in ethanol; slightly soluble in acetone; insoluble in ether, benzene, mineral oil
4. Melting Point: 101–103 °C
5. Specific Optical Rotation [α]D20: -1.5° ~ -2.3° (c=10, water)
6. pH (1% aqueous solution): 2.2–2.8 (weak acidity)
7. Hygroscopy: Slightly hygroscopic under high humidity environment
8. Thermal characteristic: No crystal water, no efflorescence

2.2 Chemical Properties

1. Molecular structure: Chiral four-carbon dicarboxylic acid with secondary hydroxyl group on C2
2. Acid-base characteristic: Two dissociable carboxyl groups, forms malate buffer system with sodium/potassium salts for pH stabilization
3. Hydroxyl reactivity: Side chain hydroxyl participates in esterification, chelation with metal ions, inhibits food oxidation browning
4. Thermal Stability: Stable below 120℃; above 150℃ undergoes dehydration to produce fumaric acid
5. Acid & Alkali Stability: Stable in weak acid/neutral medium; neutralizes rapidly with alkali to form soluble malate salts
6. Photostability: No discoloration or degradation under normal light storage
7. Compatibility: Compatible with all food additives, amino acids, cosmetic raw materials; incompatible with strong oxidants, concentrated alkaline substances

3. Main Application Fields

3.1 Food & Beverage Industry (Core Usage)

1. Acidity regulator for fruit drinks, carbonated beverages, candies, jams, baked goods; delivers mild natural fruit sourness
2. Antioxidant stabilizer to prevent fruit raw material browning, extend food shelf life
3. Flavor synergist to enhance fruit aroma and reduce harsh sour taste of citric acid

3.2 Sports & Health Nutrition Supplement

1. Energy recovery raw material for fitness supplements; relieves lactic acid accumulation after exercise, alleviates muscle soreness
2. Functional tablet raw material for liver metabolism support and electrolyte balance regulation

3.3 Pharmaceutical Raw Material

1. Excipient for oral tablets, effervescent granules, oral liquid; adjusts formulation taste and stabilizes pH
2. Chelating auxiliary for mineral supplement preparations (calcium/magnesium malate) to improve mineral absorption

3.4 Cosmetic & Personal Care Raw Material

4. Quality Specification Table