Transglutaminase-induced or citric acid-mediated cross-linking of whey proteins to tune the characteristics of subsequently desolvated sub-micron and nano-scaled particles.
Whey proteins were inter-connected either by the enzyme transglutaminase or citric acid and then desolvated with ethanol to generate particles. Both samples comprised of sub-micron (>300 nm) and nano-scaled (~100 nm) particles based on the hydrodynamic size measurements. Enzyme-induced cross-linking of proteins yielded more monodisperse particles and decreased the mean size of the major (nano-scaled) fraction of particles. Scanning electron microscopy images revealed a spherical morphology for all samples with mean sizes of <40 nm. Atomic force microscopy indicated a lower height for the particles from enzymatically cross-linked proteins. The mediating role of citric acid in bridging the proteins was confirmed by Fourier transform infrared spectroscopy. Differential scanning calorimetry indicated that pre-heating of protein solution before cross-linking and desolvation denatured the proteins entirely. In vitro degradation of whey protein particles in a simulated gastric fluid demonstrated that cross-linking of whey proteins before desolvation stage enhanced significantly the digestion stability of particles.
Department of Food Science and Engineering, University College of Agriculture and Natural Resources, University of Tehran , Karaj , Iran.
Leila
L
Bagheri
Mohammadsaeed
M
Yarmand
Ashkan
A
Madadlou
Mohammad E
ME
Mousavi
D000156:Aconitic Acid / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared; D011503:Transglutaminases / Q000737:chemistry*
D003432:Cross-Linking Reagents; D000156:Aconitic Acid; D011503:Transglutaminases
Citric acid; cross-linking; desolvation; transglutaminase; whey protein particles