Physicochemical, antioxidant, calcium binding, and angiotensin converting enzyme inhibitory properties of hydrolyzed tomato seed proteins

The objective of this was to determine the impact of enzymatic hydrolysis on the multifunctionality of tomato seed protein hydrolysates (TSPH) and their physicochemical properties. The enzymatic hydrolysis was performed using alcalase and two factors response surface methodology. The best conditions were 131.4 min and 3% enzyme/substrate (E/S) for antioxidant activity; 174.5 min and 2.93% E/S for angiotensin-converting enzyme (ACE) inhibition; and 66.79 min and 2.27% E/S for the calcium binding. Antioxidant and ACE hydrolysates were characterized by higher solubility, zeta potential, and thermal stability while properties of the calcium binding hydrolysate were only minimally affected by the enzymatic hydrolysis. Gel electrophoresis showed that molecular weights of polypeptides in the calcium binding TSPH were higher compared to those in ACE and antioxidant TSPHs. This was due to the low degree of hydrolysis of the calcium binding hydrolysate. Practical applications: Nowadays, different protein sources are used to produce protein hydrolysates containing bioactive peptides that can help alleviate oxidation of foods, oxidative stress, and chronic conditions (e.g., hypertension, diabetes, cardiovascular disorder). Hydrolyzed proteins also have the potential to increase mineral absorption through the formation of mineral-binding complexes.