Structural modification in condensed soy glycinin systems following application of high pressure

Molecular Functionality of Plant Proteins from Low- to High-Solid Systems with Ligand and Co-Solute

“…Plant globular proteins, extracted from legume seeds, exhibit structure formation as for the animal counterparts with some variation according to their physicochemical fingerprints [32]. Thus, the β-sheet content of globulins in soy, kidney bean and field pea protein isolates relates positively to the small deformation properties of firmness and yield strength [12,33]. Large deformation properties depend primarily on the number of disulfide bridges.…”

“…It was confirmed that the stabilisation of protein networks requires an unfolding and realignment of the secondary structure, assisted by the formation of disulfide bridges, hydrogen bonds and hydrophobic interactions [11]. Distinct variations in the proportion of α-helix and β-sheet was recorded upon thermal and non-thermal treatment, with aqueous solutions at low and intermediate levels of solids (< 50% w/w) being more susceptible to processing, as compared to the high solid pastes (80% w/w) of soy glycinin [12]. In the case of pea protein isolates, heat treatment induced molecular denaturation that increased the β-sheet and reduced the α-helix and random coil contents.…”

High pressure effects on the structural functionality of condensed globular-protein matrices

“…3 for condensed preparations of globular proteins. In doing so, samples were pressurised at 600 MPa for 15 min, subjected to oscillatory frequency sweeps thereafter, and shear modulus data were superposed using the method of reduced variables to produce a set of shift factors, a T , as a function of experimental temperature [78,79]. Modeling splits into two parts, with experimental data that lie above T g being described by the combined WLF equation-free volume theory, whereas viscoelastic functions at the lower temperature range follow the predictions of the modified Arrhenius equation.…”

“…In the case of soy glycinin, for example, deconvolution of the Amide I band showed that thermal treatment decreased the ␣-helix content about 20% compared to the native morphology. However, in condensed soy glycinin preparations there is considerable stability in the ␣-helix, where pressurised materials from 50 to 80% solids exhibit contents similar to the atmospheric counterparts [78]. Literature then argues that the resistance of globular proteins to high pressure is ranked as follows:…”

“…Effect of temperature on the viscoelastic function of shift factor for pres-80% (w/w) solids (from[78,79], with permission).…”