Investigating the Effect of Protease Enzyme Type and Hydrolysis Time on the Antioxidant Properties of Flaxseed Meal (Linum usitatissimum) Protein Hydrolysates

In this research, the effect of protease enzyme type (pepsin and pancreatin) and hydrolysis time (40-200 minutes) on the degree of hydrolysis and antioxidant properties (DPPH radical scavenging activity, Fe chelating activity, Fe reducing power and total antioxidant capacity) of flaxseed meal protein hydrolysates was investigated. The results showed that increasing the hydrolysis time increased the degree of hydrolysis, and the samples obtained from pancreatin had a higher degree of hydrolysis than pepsin. The highest activity of Fe2+ chelating (53.71 ± 0.45%) and Fe3+ reduction (1.32 ± 0.02, absorbance at 700 nm) was achieved by pancreatin after 200 minutes of hydrolysis. Pancreatin samples were more capable of inhibiting DPPH free radicals than pepsin, and their activity increased with increasing time up to 160 minutes. The highest total antioxidant capacity (1.36 ± 0.08 absorbance at 695 nm) among the samples was obtained after 160 minutes of hydrolysis with pancreatin. The antioxidant capacity of flax seed protein hydrolysates in inhibiting DPPH radical, Fe chelating activity, and total antioxidant capacity was lower than the antioxidant capacity of vitamin C at a concentration of 50 (mg/ml), but it had more Fe reducing power than vitamin C. Therefore, it can be concluded that compared to pepsin, pancreatin had a greater ability to produce flaxseed protein hydrolysates with significant antioxidant properties. According to the results, flaxseed protein hydrolysates from pancreatin enzyme and a hydrolysis time of 160 minutes have the ability to be used in food formulations to produce functional products.