The effect of high hydrostatic pressure on the structure of whey proteins-guar gum mixture.

The effect of high hydrostatic pressure (HHP) on the structural properties of whey protein concentrate (WPC) and guar gum mixture has been investigated at pH 5. WPC (6 % w/v) and guar gum (0.25 % w/v) mixture was freeze dried after adjusting pH and treated at different pressure levels (0-600 MPa) for 0-30 min. The solubility of treated powders decreased significantly (p < 0.05) as treatment time and pressure levels increased. Thermal analysis showed an increase in denaturation temperature after HHP treatment at 600 MPa. A more crystalline structure was observed in samples treated with 600 MPa for 20 and 30 min. With increasing pressure and time, particle size of the samples increased and the highest particle size was belonged to sample treated at 600 MPa for 30 min (759.66 nm). SEM results exhibited that by applying the pressure, irregularity of shapes and particle size increased while the apparent cracks decreased. FTIR results indicated that HHP treatment changed shift in bond and peak intensity. As reported in the current study, the application of HHP treatment as a green physical technology on protein-polysaccharide mixture could be used to improve interaction of protein and polysaccharide.

Utilization of chickpea protein isolate and Persian gum for microencapsulation of licorice root extract towards its incorporation into functional foods.

This study aimed at the fabrication of licorice extract (LE)-loaded microparticles by complex coacervation, using chickpea protein isolate (CPI) and soluble fraction of Persian gum (SFPG). The LE-loaded microparticles with the highest encapsulation efficiency (97.87%) and loading capacity (11.35%) were obtained at pH 3 and CPI: SFPG ratio, core: coating ratio, and polymer concentration of 2, 1.5, and 2, respectively. The LE-loaded microparticles (2-15 µm) possessed heterogeneous microstructure, and the Fourier-transform infrared spectroscopy data confirmed the pronounced effect of electrostatic interactions and hydrogen bonding. The thermostability, amorphous structure, and color of the LE-loaded microparticles were significantly enhanced, compared to free LE. The sensory evaluation of the model beverages containing LE-loaded microparticles revealed that the microencapsulation was able to mask the bitter aftertaste and color of the extract. Thus, the results of this research confirm the potential of CPI-SFPG complex coacervates for the efficient delivery of glycyrrhizin via incorporation into functional food products.