Angiotensin I-converting enzyme inhibitory peptides produced from tuna cooking juice hydrolysate by continuous enzymatic membrane reactor.

Angiotensin I-converting enzyme (ACE) inhibitory peptides were derived from tuna cooking juice (TCJ) hydrolysis by alcalase in the continuous enzymatic membrane reactor (cEMR) coupling with 1 kDa MWCO membrane. The permeated sample from cEMR for 510 min of hydrolysis was purified by size exclusion chromatography in Sephadex G-25 column. A fraction exhibited the highest ACE inhibitory activity was further separated by RP-HPLC, resulting two fractions showed highest ACE inhibitory activities. The molecular weight (MW) and amino acid sequences of peptides from both fractions were determined using LC-MS/MS. Two potential ACE inhibitory peptides were obtained and showed molecular weight of 959.46 and 1,141.29 Da. PRACTICAL APPLICATIONS: Tuna cooking juice (TCJ) usually was either used as protein source of feed meal or directly discharged to wastewater treatment system. However, it contains water-soluble proteins in a group of sarcoplasmic protein, which is small water-soluble proteins and easily hydrolyzed to small peptides. In this study, the active peptides, angiotensin I-converting enzyme inhibitory peptides (MW of 959.46 and 1,141.29 Da), obtained from TCJ hydrolysate and identified by LC-MS/MS would be a beneficial ingredient for nutraceuticals and functional food against hypertension.