Antihypertensive peptides from hydrolyzed proteins of Pleurotus spp.: Production, in vitro digestion and identification

This study aimed to investigate in vitro antihypertensive property of protein hydrolysates from Pleurotus spp. mushrooms obtained through enzymatic hydrolysis. FlavourzymeTM 500 L, AlcalaseTM 2.4 L and NeutraseTM 0.8 L were used alone and in combination using an experimental design of mixtures. Antihypertensive activity was determined by angiotensin-converting enzyme (ACE) inhibition and the simulated in vitro digestion was performed according to the INFOGEST protocol. Results showed that most of the protein hydrolysates obtained displayed higher ACE inhibitory activity than non-hydrolyzed protein, ranging from 15.76% and 50.87% inhibition. The highest ACE inhibition and the lowest TCA soluble protein content (52.09 %) were detected for the protein hydrolysates obtained by using the binary mixture of FlavourzymeTM 500 L and AlcalaseTM 2.4 L in equal proportions. Hydrolysis kinetics showed no significant difference in ACE inhibitory activity between 20 and 120 minutes of enzymatic reaction. The fraction with molecular weight between 3 and 5 kDa obtained after ultrafiltration showed the most contribution for ACE inhibitory activity (47% inhibition). After simulated digestion, the hydrolysates maintained a significant ACE inhibition capacity, indicating the resistance of the peptides to the action of gastrointestinal enzymes. Through proteomic analysis, 26 peptides were identified and the sequences LPILP, IPLLP, PLLPQ and VIQYDPPQ were considered potentially antihypertensive.