Physicochemical and functional properties of protein isolate produced from Australian chia seeds

• Physicochemical and functional properties of chia seed protein isolate (CPI) were investigated.
• Solubility of CPI increased with increase pH, temperature and NaCl concentration.
• Foaming properties were strongly dependent on the concentration and pH.
• Spray-dried CPI was least denatured among vacuum and freeze dried samples.
• Solubility and foaming properties of spray-dried CPI were superior to freeze and vacuum-dried CPI.

Protein was isolated from Australian chia seeds and converted to powders using spray, freeze and vacuum drying methods, to investigate the effect of drying methods on physicochemical and functional attributes of chia-seed protein isolate (CPI). It was found that there was no significant difference in the proximate composition; however vacuum dried CPI (VDCPI) had the highest bulk density and oil absorption capacity, whereas spray dried powder (SDCPI) demonstrated the highest solubility, water absorption capacity and lowest surface hydrophobicity. Solubility of all powders was higher at elevated temperature and alkaline pH. Foaming capacity and foam stability of CPI were found to increase with increasing pH and protein concentration. SDCPI was the least denatured and VDCPI the most denatured, demonstrating the poorest solubility and foaming properties of the latter. These findings are expected to be useful in selection of a drying process to yield chia seed protein powders with more desirable functionality.