Modified Starch(CAS#9045-28-7)–Starch Acetate E1420 Food Thickener and Stabilizer

1. Properties:

• Appearance and Physical Form: Modified starch (starch acetate, CAS#9045-28-7) is a white to off-white free‑flowing powder produced by acetylation of native starch (derived from corn, potato, tapioca, or other sources). The product is odorless or has a very faint characteristic starch odor.
• Solubility: Starch acetate is soluble in both cold and hot water (degree of substitution‑dependent), with a substantially lower gelatinization temperature compared to native starch. Highly acetylated starches (DS > 0.5) can be >90% soluble in room-temperature water. The product is insoluble in organic solvents such as ethanol (96%) and hydrocarbons.
• Chemical Properties: Starch acetate is an ester of starch with acetic anhydride or vinyl acetate. The acetylation introduces acetyl groups (‑COCH₃) into the starch molecule, improving hydrophobicity and reducing intermolecular hydrogen bonding, which results in enhanced cold water solubility, improved freeze-thaw stability, excellent clarity, low gelatinization temperature, reduced retrogradation (syneresis prevention), increased thickening efficiency, and good shear stability. The degree of substitution (DS) can range from 0.1 to 1.5, directly influencing solubility, viscosity, and functional properties. Acetylation improves paste clarity and decreases gelling tendencies, making starch acetate particularly suitable for processed and frozen food applications.

2. Applications:

Food & Beverage Industry (E1420):

• Soups, Sauces, Dressings & Gravies: Starch acetate is widely used as a thickener, stabilizer, and texturizing agent. It prevents syneresis (water separation) and provides a smooth, glossy appearance with a clean flavor profile.
• Frozen Foods & Ready Meals: Due to its excellent freeze-thaw stability, starch acetate maintains viscosity and texture after multiple freeze-thaw cycles, making it ideal for frozen meals, frozen vegetables in sauce, and ice cream.
• Bakery & Fillings: Used in pie fillings, fruit preparations, bakery glazes, and custard powders to improve viscosity, texture, and stability.
• Dairy Products & Processed Cheese: Functions as a thickening and stabilizing agent in puddings, yogurt, processed cheese, cheese spreads, and imitation cheese.
• Meat & Seafood Products: Acts as a binder and water-retention agent in sausages, surimi, minced meat products, meat analogs, and fish products; also used in canned meat and poultry formulations.
• Instant Noodles & Pasta: Starch acetate reduces oil absorption, improves noodle elasticity, increases rehydration capacity and transparency, and prevents starch dissolution (turbidity) in soup.
• Snacks & Confectionery: Used as a binder and coating agent in chips, extruded snacks, jelly candies, wine gums, and gummy confections to improve texture and mouthfeel.
• Baby Food & Nutritional Products: Serves as a thickening agent and stabilizer in infant cereals and nutritional formulations.
• Beverages: Used as a clouding and stabilizing agent in powdered drink mixes and flavored beverages.

Textile Industry:

• Warp Sizing Agent: Modified starch is used as a sizing agent for cotton, polyester/cotton blends, and synthetic yarns. It improves yarn strength, reduces hairiness and breakage during weaving, and is easily removed during desizing operations.
• Textile Printing Thickener: Provides precise color definition, uniform dye transfer, and is easily washed off after printing.
• Fabric Finishing: Used as a finishing agent to impart stiffness and body to fabrics.

Paper & Packaging Industry:

• Surface Sizing Agent: Improves paper strength, printability, surface smoothness, ink holdout, and resistance to oil/grease penetration.
• Paper Coating Binder: Acts as a binder for pigments (clay, calcium carbonate) in paper coating formulations, improving coating uniformity and print quality.
• Corrugating Adhesives: Used in adhesive formulations for corrugated board and paper bags.
• Food Packaging Adhesives: Functions as an adhesive additive for food contact paper and board applications.

Pharmaceutical Industry:

• Tablet Binder: Used as a tablet binder and filler excipient in solid dosage forms to improve tablet hardness and cohesion.
• Disintegrant: Aids in tablet disintegration for faster drug release upon ingestion.
• Capsule Filler: Used as an inert filler in hard and soft gelatin capsules.
• Topical Formulations: Functions as a thickener and consistency agent in creams, ointments, and pastes.

Cosmetics & Personal Care:

• Thickening Agent: Used in lotions, creams, gels, and shampoos to build viscosity and improve product texture.
• Film Former: Provides smooth, non-greasy film on skin and hair for protection and conditioning.
• Skin Conditioning Agent: Acts as an emollient and soothing agent.
• Oil Control Powders: Used in facial powders and foundations as an oil-absorbing and mattifying agent.
• Hair Care: Provides conditioning and anti-static effects in hair styling products.

Adhesives & Binders:

• Industrial Adhesives: Used as a binder in water-based adhesives for paper laminating, wallpaper pastes, envelope adhesives, and label pastes.
• Construction Binders: Used in gypsum board manufacturing and drywall joint compounds.

Other Industrial Applications:

• Biodegradable Films: Used in the production of biodegradable packaging films and edible coatings for food preservation.
• Mining & Oilfield: Functions as a flocculant and rheology modifier in mineral processing and drilling fluid applications.
• Detergents: Used as a processing aid and anti-redeposition agent in laundry detergents.

3. Preparation Method:

• Laboratory Method: Starch acetate can be prepared in the laboratory by heating native starch with acetic acid and acetic anhydride in the presence of an acid catalyst (e.g., sulfuric acid or sodium hydroxide) in a stirred reactor at 84–92°C for 4 hours, achieving a degree of substitution of 0.1–1.5. Microwave heating has also been demonstrated as an alternative method to accelerate acetylation.
• Industrial Process: Industrial production of food-grade starch acetate (E1420) follows an aqueous suspension acetylation process: (1) Slurry Preparation: Native starch (from potato, corn, tapioca, or wheat) is suspended in water at 30–45% solids content. (2) Acetylation: Acetic anhydride (2–10% based on starch weight) is slowly added to the starch slurry under controlled pH (7.0–10.0) using sodium hydroxide as the catalyst and neutralizing agent. The reaction is carried out at 25–40°C for 1–4 hours. (3) Neutralization & Washing: After the desired degree of substitution is reached, the reaction mixture is neutralized with hydrochloric acid or sulfuric acid, and the starch acetate is washed multiple times with water to remove residual acetic acid, anhydride, and by‑products (sodium acetate). (4) Drying & Milling: The purified starch acetate is dried in flash dryers or rotary dryers to a moisture content of 5–14%, then milled and sieved to the desired particle size (typically 80–200 mesh). (5) Blending & Packaging: The finished product is blended for consistency and packaged in 25 kg multi‑wall bags or FIBCs. For pharmaceutical applications, additional purification steps are performed to meet regulatory pharmacopoeial standards. For specialty industrial grades, parameters such as degree of substitution, viscosity, and ash content are precisely controlled.

4. Safety Information:

• Hazard Classification: Modified starch (starch acetate, CAS#9045-28-7) is generally classified as non‑hazardous or of very low hazard under GHS/CLP Regulation (EC) No 1272/2008. High dust concentrations may carry hazard statement H335 (May cause respiratory irritation). Hazard symbol: GHS07 (for certain dusty grades). Signal word: Warning. The product is not classified as flammable, explosive, or environmentally hazardous under standard criteria.
• Health Hazards:
  • Inhalation: Inhalation of airborne starch dust may cause mild respiratory tract irritation, coughing, sneezing, or throat discomfort in sensitive individuals. Prolonged exposure to high dust concentrations may lead to respiratory discomfort.
  • Skin Contact: Generally non‑irritating to intact skin; may cause mild mechanical irritation due to abrasive effect of powder in sensitive individuals.
  • Eye Contact: Fine dust particles may cause mild mechanical irritation. Rinse with water.
  • Ingestion: Starch acetate is safe for human consumption as a food additive (E1420). Oral toxicity is very low, with LD₅₀ > 15,000 mg/kg in rats. Long-term animal feeding studies (2 years at dietary levels up to 30%) showed no adverse effects on mortality, food intake, haematology, or blood biochemistry. Digestibility is approximately 68–81% of native starch.
• First Aid Measures:
  • Inhalation: Move person to fresh air. Keep at rest in a position comfortable for breathing. If respiratory irritation persists, seek medical advice.
  • Skin Contact: Wash skin with plenty of soap and water. Remove contaminated clothing. Seek medical advice if irritation develops.
  • Eye Contact: Rinse cautiously with plenty of water for several minutes. Remove contact lenses if present and easy to do. Seek medical attention if eye irritation persists.
  • Ingestion: Rinse mouth immediately. If a large amount is ingested, seek medical attention. Do not induce vomiting unless directed by medical personnel.
• Fire & Explosion Hazards: Modified starch is not combustible but may burn if involved in a fire. Accumulated starch dust may form explosive concentrations in air when disturbed and dispersed, as with any organic dust. In case of fire, use water spray, foam, dry powder, or CO₂ as extinguishing media. Thermal decomposition may produce carbon monoxide, carbon dioxide, and acetaldehyde fumes.
• Environmental Precautions: Starch acetate is fully biodegradable as a natural polysaccharide derivative. Degradation products are non‑toxic under normal environmental conditions. Avoid large‑scale release into natural water bodies, drains, or soil. Comply with local environmental regulations for disposal.
• Storage & Stability: Store in tightly closed, moisture‑proof containers in a cool, dry, well‑ventilated area away from direct sunlight, heat sources, and strong oxidizers. Starch acetate is hygroscopic; exposure to atmospheric moisture leads to caking, lump formation, and reduced functional performance. Under recommended storage conditions (room temperature, low humidity, 25°C), shelf life is 24 months (2 years) from date of manufacture in sealed original containers, with some high‑stability grades rated for up to 60 months (5 years). Once opened, use the product quickly to prevent moisture regain.
• Regulatory Compliance: Modified starch, starch acetate (CAS#9045-28-7, INS 1420) is listed on EINECS (232-536-8), TSCA, DSL, AICS, NZIoC, ENCS, KECI, and other regional chemical inventories. As a food additive E1420, it complies with the purity criteria of Regulation (EU) No 231/2012 and is approved for use in food products under Commission Regulation (EU) No 1333/2008. In the USA, it is affirmed as GRAS (Generally Recognized as Safe) under FDA 21 CFR § 172.892 and approved for food contact substances under 21 CFR § 175.105. The JECFA (Joint FAO/WHO Expert Committee on Food Additives) has assigned an ADI (Acceptable Daily Intake) of “not specified,” indicating the highest level of safety for food additives. Always consult the Safety Data Sheet (SDS) for complete safety, environmental, and regulatory information specific to each product grade and application jurisdiction.