Extrusion studies of mixtures containing certain meat offals: Part 2-textural properties

Area of Science:

• Food Science
• Material Science
• Biotechnology

Background:

• Thermoplastic extrusion is a key process for creating novel food products from plant and animal sources.
• Understanding the textural properties of extruded soy-offal products is crucial for their application as food ingredients or meat analogues.

Purpose of the Study:

• To investigate the impact of extrusion temperature, offal source, and protein extraction method on the texture of soy-offal composite products.
• To determine the suitability of different offal preparations for use in food applications.

Main Methods:

• Soy grits were extruded alone and with bovine or porcine offal (20-35%) at various temperatures (140-190°C).
• Offal sources included untreated, alkali-extracted, and sodium dodecyl sulphate (SDS)-extracted proteins from lung and tripe.
• Instrumental texture profile analysis (hardness, elasticity, cohesiveness, gumminess, chewiness) and shear force measurements were performed.

Main Results:

• Extrusion temperature had a lesser effect on texture than offal preparation or incorporation level.
• SDS-extracted tripe protein yielded harder, gummier, and chewier products requiring more shear force compared to untreated offal.
• Alkali-extracted offal protein resulted in brittle products with poor internal structure, while SDS-extracted protein produced tough products.

Conclusions:

• The method of offal protein preparation significantly influences the textural characteristics of extruded soy products.
• SDS-extracted protein creates tougher products, while alkali-extracted protein leads to brittle textures.
• Textural differences suggest varied applications for these soy-offal composites as meat analogues or extenders.