Effects of extrusion on the emulsifying properties of rumen and soy protein

Ana C C Silva, Elizabeth P G Arêas, Marcelo A. Silva, José Alfredo G Arêas

Research output: Contribution to journalArticlepeer-review

24 Citations (SciVal)


Defatted rumen protein and soy protein concentrate were extruded in a 15.5:1 L/D single-screw extruder at the optimum conditions for their expansion (150°C and 35% moisture, and 130°C and 35% moisture, respectively). Emulsions were produced with these proteins and studied by rheology and time domain low-resolution 1H nuclear magnetic resonance (TD-NMR). Extrusion increased storage modulus of rumen protein emulsions. The opposite was observed for soy protein. Mechanical relaxation showed the existence of three relaxing components in the emulsions whose relative contributions were changed by extrusion. Likewise, spin-spin relaxation time constants (T 2) measured by TD-NMR also showed three major distinct populations of protons in respect to their mobility that were also altered by extrusion. Extrusion increased surface hydrophobicity of both rumen and soy protein. Solubility of rumen protein increased with extrusion whereas soy protein had its solubility decreased after processing. Extrusion promoted molecular reorganization of protein, increasing its superficial hydrophobicity, affecting its interfacial properties and improving its emulsifying behavior. The results show that extrusion can promote the use of rumen, a byproduct waste from the meat industry, in human nutrition by replacing soy protein in food emulsions.

Original languageEnglish
Pages (from-to)94-102
Number of pages9
JournalFood Biophysics
Issue number2
Early online date9 Mar 2010
Publication statusPublished - 10 Mar 2010


  • Emulsion stability
  • Food waste
  • NMR
  • Rheology
  • Upgrading

ASJC Scopus subject areas

  • Food Science
  • Biophysics
  • Analytical Chemistry
  • Applied Microbiology and Biotechnology
  • Bioengineering


Dive into the research topics of 'Effects of extrusion on the emulsifying properties of rumen and soy protein'. Together they form a unique fingerprint.

Cite this