Food-grade production of an antihypertensive casein hydrolysate and resistance of active peptides to drying and storage

A casein hydrolysis process was scaled up to produce the antihypertensive peptides αs1-CN f(90–94), with sequence RYLGY, and αs1-CN f(143–149), with sequence AYFYPEL. Previously, the hydrolysis process was optimized under food-grade conditions to obtain a maximum amount of active peptides, quantified by high-performance liquid chromatography–mass spectrometry. Ultrafiltration as a strategy for enrichment of active peptides was also evaluated. The casein-derived ingredients prepared at large scale showed potent angiotensin converting enzyme-inhibitory activity in vitro. Furthermore, these products produced a significant decrease in the systolic blood pressure of spontaneously hypertensive rats after oral administration (200–800 mg kg−1 of body weight). The active peptides RYLGY and AYFYPEL were stable during the processes of atomization, homogenization and pasteurization. This hydrolysate was incorporated into liquid yoghurt and no significant reduction of either peptide was detected during the shelf-life of the product.