Process Analysis of Gelatin Production by Alkaline Method

Gelatin is a widely used colloid in food, pharmaceutical, cosmetic, and other industries. There are various production methods, among which the alkaline method is commonly employed. Below is a detailed breakdown of the alkaline method process:
Ⅰ. Raw Material Preparation

First, raw materials rich in collagen, such as animal hides or bones, are prepared. These materials form the foundation ofgelatin production, and their quality directly impacts the final product. Therefore, raw materials must be fresh and free from contamination during selection.

 II. Alkaline Treatment

Next, the raw materials undergo alkaline treatment. The objectives are to:         

1. Remove non-collagen components (e.g., fats, impurities).
2. Partially hydrolyze collagen to enhance solubility.

Key Controls:

• Alkali Concentration: Typically 2–5% sodium hydroxide (NaOH) or 1–3% calcium hydroxide (Ca(OH)₂) solution.
• Temperature: Maintained at 15–25°C to avoid excessive hydrolysis.
• Duration: 12–48 hours (varies by raw material type and thickness).
  
  

  Ⅲ. Filtration
  After alkaline treatment, the mixture is filtered to remove solid impurities. Common methods include:

  • Fine Mesh Sieving: Using 80–100 mesh screens to separate large particles.
  • Centrifugation: For finer impurities, centrifugation at 3000–5000 rpm is optional.

  The goal is to obtain a clear, impurity-free liquid.
   Ⅳ.Concentration

  The filtered liquid is concentrated to increase gelatin concentration (typically from 5–10% to 20–30%). This is usually achieved via heated evaporation under controlled conditions:

  • Temperature: 60–70°C to prevent collagen denaturation.
  • Agitation: Continuous stirring to avoid local overheating and scorching.
    
    Ⅴ. Drying
    

    Finally, the concentrated gelatin solution is dried to produce the final product. Common drying methods include:

    1. Spray Drying: Atomizing the solution into droplets and drying with hot air (120–140°C) to form powder.
    2. Vacuum Drying: Drying at 40–50°C under vacuum to preserve gelatin’s functional properties.

    Whatever method is adopted, strict control of temperature and time is required to ensure the quality and stability of the product.