As a significant food additive and industrial material, the scientific nature and application value of gelatin warrant in-depth exploration. This article systematically examines its raw material sources, physicochemical properties, application domains, and production technologies.

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I. Raw Material Sources and Production Principles

Gelatin is a thermally denatured product of collagen, primarily derived from collagen components in animal connective tissues. Industrial production typically utilizes bones, dermal layers, and tendons from mammals such as pigs and cattle. Through acid-base treatment or enzymatic hydrolysis, collagen is extracted and then thermally denatured to obtain gelatin. The depolymerization of collagen's tertiary structure during production is critical to forming gelatin's unique properties.

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II. Physicochemical Characteristics

1. Physical Properties
   Gelatin appears as a colorless to pale yellow translucent solid, existing in powder, flake, or granular forms. Its relative molecular weight ranges between 50,000–100,000 Dalton, with a density of 1.3–1.4 g/cm³. It exhibits typical amphoteric electrolyte characteristics, with an isoelectric point (pI) between pH 4.8–5.2.
2. Hydration Behavior
   Gelatin's swelling behavior in water follows the Flory-Rehner theory: at ambient temperatures, it forms a hydrated gel network, while heating above 35°C induces a helix-to-coil conformational transition, creating a thermally reversible sol. This behavior originates from the triple-helix structure formed by glycine-proline-hydroxyproline repeating sequences in its molecular chains.

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III. Functional Properties and Applications

1. Food Industry
   • Rheology Modifier: Forms three-dimensional network structures, providing elastic modulus (1–10 kPa) in cheeses and inhibiting ice crystal growth (particle size <50 μm) in frozen desserts.
   • Emulsion Stabilizer: Reduces oil-water interfacial tension to 10–20 mN/m, enhancing emulsion stability.
   • Gelling Agent: Creates gel networks with strengths of 200–300 Bloom, applied in meat product hydration and confectionery molding.
2. Pharmaceutical Sector
   • Capsule Matrix: Complies with USP standards, with disintegration time <15 minutes.
   • Plasma Substitute: Molecular weight cutoff range of 30–70 kDa.
   • Drug Delivery Carrier: Enables pH-sensitive controlled release.
3. Cosmetics
   • Film-Forming Agent: Produces 1–5 μm-thick moisturizing films.
   • Viscosity Modifier: Increases system viscosity to 500–2000 mPa·s.
   • Suspension Stabilizer: Maintains particle Zeta potential above ±30 mV.

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IV. Advancements in Modern Production Technologies

Leading enterprises like Gelken employ integrated extraction technologies to enhance product performance:

1. Physical Separation: Ultrafiltration membranes (10 kDa molecular weight cutoff) enable precise molecular weight fractionation.
2. Ethanol Gradient Precipitation: Controlled alcohol concentrations (40–60%) improve purity (>98%).
3. Lyophilization Optimization: Maintains porous structures (porosity >80%) and accelerates reconstitution speed (<30 seconds).

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V. Market Trends and Challenges

The global gelatin market grows steadily at 5–6% annually, with notable trends:

• Pharmaceutical-grade products now account for 35% of the market.
• Plant-based gelatin alternatives are under accelerated development (current share <5%).
• Nano-gelatin (particle size <100 nm) shows promise in targeted drug delivery systems.

Key Technological Challenges:

1. Enhancing thermal stability (target: 80°C tolerance for 2 hours).
2. Ensuring microbial safety (endotoxin levels <0.25 EU/mg).
3. Developing sustainable processes (30% energy reduction).

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This biomacromolecule, with its intricate structure-function relationships, continues to expand in scientific significance and application potential. As materials science and biotechnology converge, gelatin-based functional materials are poised to unlock greater value in emerging fields such as tissue engineering and flexible electronics.