Safflower Protein Hydrolysates: Physicochemical, Functional Properties and Antioxidant Activities

This study aimed to investigate the effect of enzymatic hydrolysis on the physicochemical, functional, and antioxidant properties of safflower protein isolate and hydrolysates. Isolated safflower protein was hydrolyzed by both Alcalase and Flavourzyme at the degree of hydrolysis of 2%, 4%, 6%, 8%, and 10%. Safflower protein hydrolysates exhibited a lighter color (3.74%-8.79%) and reduced redness (69.11%-102.85%) with lower cohesiveness (15.29%-21.76%) and better flowability (25.91%-40.27%) compared to the protein isolate. Moreover, the surface hydrophobicity of safflower protein isolate decreased up to 73.18% with hydrolysis, while solubility increased up to 54.42% at pH 4-7. Safflower proteins hydrolyzed with Alcalase had higher oil binding, foaming, and emulsion capacities than samples hydrolyzed with Flavourzyme, while their water holding capacities were lower. Furthermore, safflower proteins hydrolyzed with Alcalase at an 8% degree of hydrolysis displayed the highest foaming capacity (up to 3.89 times) and emulsion capacity (up to 1.23 times) in all samples. However, it had poor foam (up to 67.06%) and emulsion stability (up to 74.35%). Additionally, safflower protein hydrolysates demonstrated higher ABTS^•+ and DPPH radical scavenging activity. Overall, safflower protein hydrolysates showed better physicochemical, functional, and antioxidant properties than protein isolates, depending on enzyme types and degree of hydrolysis.