High Quality Food Grade Propyl Gallate Powder 212.21 Molecular Weight CAS 121-79-9 Hot Sell Antioxidants Type Bozewon Brand 2

Propyl Gallate (PG): A Comprehensive Overview

Propyl Gallate, also known as Propylgallate or PG, is a widely used synthetic antioxidant with the chemical formula C₁₀H₁₂O₅ and molecular weight of 212.2 g/mol. It is chemically known as propyl 3,4,5-trihydroxybenzoate or propyl ester of gallic acid. This compound is produced through the esterification reaction between gallic acid and n-propanol under acidic dehydrating conditions with heating .

Physical and Chemical Properties

Propyl Gallate appears as a white to pale yellow-brown crystalline powder or milky white needle-like crystals. It is odorless with a slightly bitter taste, and its aqueous solution is tasteless. The compound has the following characteristics:

• Melting point: 146–150°C
• pH of 0.25% aqueous solution: approximately 5.5
• Solubility: Easily soluble in ethanol, hot water, ethyl acetate, propylene glycol, glycerin, cottonseed oil, peanut oil, and lard; slightly soluble in fats and water
• Stability: Relatively stable under normal conditions, but unstable under light and decomposes when exposed to illumination
• Moisture absorption: Has hygroscopic properties
• Metal ion reaction: Reacts with copper and iron ions to produce purple or dark green coloration
• Heat resistance: Poor heat stability, though it is relatively stable during thermal processing compared to some other antioxidants

Primary Applications

Propyl Gallate is primarily used as a fat-soluble antioxidant in various industries:

1. Food Industry: It is extensively used in edible oils, fried foods, dried fish products, biscuits, instant noodles, instant rice, nut canning, and cured meat products. It is particularly effective in stabilizing soybean oil, cottonseed oil, palm oil, unsaturated fats, and hydrogenated vegetable oils ChemicalBook +1 .

2. Cosmetics Industry: Used in cosmetic formulations to prevent oxidation of oils and fats, thereby extending product shelf life.

3. Pharmaceutical and Research Applications: In fluorescence microscopy, Propyl Gallate serves as an anti-fade reagent to reduce photobleaching of fluorescent probes such as rhodamine and fluorescein. It has also been reported to exhibit antimicrobial activity and may function as a hepatoprotective antioxidant agent

Antioxidant Mechanism and Synergy

The antioxidant action of Propyl Gallate works by reacting with free radicals under aerobic conditions, inhibiting the activity of oxidase enzymes, and effectively preventing lipid oxidation. Its antioxidant efficacy is significantly enhanced when used in combination with synergists such as citric acid, or when mixed with other antioxidants like BHA (Butylated Hydroxyanisole) and BHT (Butylated Hydroxytoluene). Studies indicate that PG combined with these additives provides superior antioxidant protection compared to single-component use

Safety and Regulatory Statu

Propyl Gallate has been used as a major antioxidant in fatty materials since 1947 and is generally recognized as safe when used within regulatory limits. However, some research has raised concerns:

• Contact Sensitization: A study found that Propyl Gallate caused contact dermatitis in 5 out of 10 people who applied it for approximately 20 days. Guinea pig experiments showed it has contact sensitization potential comparable to dinitrochlorobenzene .
• Reproductive Health: Some recent research suggests that high-dose exposure to PG may influence reproductive health in humans and animals, including potential effects on oocyte meiotic maturation through mitochondrial dysfunction and DNA damage .
• Tolerance Hypothesis: Despite sensitization potential in controlled studies, no widespread reports of contact sensitization have been documented in the United States. Researchers propose that induced immunological unresponsiveness (tolerance) may explain this discrepancy .

Usage Guidelines and Precautions

• Recommended Usage Levels: Regulatory agencies set maximum usage limits for Propyl Gallate in different food categories. Users should always comply with local food safety regulations.
• Storage: Should be stored in a cool, dry place away from light to prevent decomposition.
• Metal Contamination: Avoid contact with copper and iron containers or equipment, as color changes may occur.
• Allergy Considerations: Individuals with sensitivities to phenolic compounds should exercise caution.

Conclusion

Propyl Gallate remains one of the most widely used antioxidants in the food, cosmetic, and pharmaceutical industries due to its effective lipid oxidation prevention capabilities. While generally safe within approved limits, ongoing research continues to evaluate its long-term safety profile, particularly regarding reproductive health and sensitization potential. Users should follow regulatory guidelines and best practices for safe handling and application.