April 21/Beijing/Journal of Farming -- According to recent research from Beijing, People's Republic of China, "Removal of salts from protein hydrolysate mixtures on a large scale is very difficult and relatively inefficient. Selecting practical proteinase system and hydrolysis conditions for the production of whey protein isolate (WPI) enzymatic hydrolysates with high angiotensin I-converting enzyme (ACE) inhibitory activity and low ash content is very useful."

"The effect of alcalase, neutrase, trypsin and their combined system, i.e. alcalase-neutrase and trypsin-neutrase, under two different hydrolysis conditions, i.e. pH-controlled and pH-spontaneous drop, on the formation of ACE-inhibitory peptides and the characteristics of WPI hydrolysate was investigated. The ACE-inhibitory activity of WPI hydrolysate obtained with alcalase was significantly higher than that of its trypsin or neutrase hydrolysate obtained at the same hydrolysis time by both pH-controlled and pH-spontaneous drop method (P<0.05). The WPI hydrolysate obtained after three hours incubation with alcalase plus two hours with neutrase under pH-spontaneous drop condition possessed the highest ACE-inhibitory activity of 54.30% and the lowest ash content of 2.95%," wrote L. Wang and colleagues, China Agricultural University.