Abstract
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 language | English |
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Pages (from-to) | 94-102 |
Number of pages | 9 |
Journal | Food Biophysics |
Volume | 5 |
Issue number | 2 |
Early online date | 9 Mar 2010 |
DOIs | |
Publication status | Published - 10 Mar 2010 |
Funding
Acknowledgments The authors are grateful for the financial support from FAPESP and CNPq, Brazil.
Keywords
- Emulsion stability
- Food waste
- NMR
- Rheology
- Upgrading
ASJC Scopus subject areas
- Food Science
- Biophysics
- Analytical Chemistry
- Applied Microbiology and Biotechnology
- Bioengineering