Separation and identification of ACE inhibitory peptides from cashew nut (<i>Anacardium occidentale</i> Linnaeus) protein

<p>Cashew nut protein powder was hydrolysed by alkaline protease to prepare ACE inhibitory peptides. Results showed that the optimum conditions were: substrate concentration, 7 g/100 mL; amount of enzyme, 3%; pH, 10.5; hydrolysis time, 6 h; and temperature, 45°C. Under these conditions, ACE inhibitory rate was 57.45%. ACE inhibitory peptides were filtered using an ultrafiltration membrane of different molecular weights and Sephadex G-15 gel column. We found that the molecular weight was <3000 Da, and the ACE inhibitory rate concentration was 100 mg/mL. The M<sub>2</sub> component, which was the most active component in ACE inhibitory peptides, yielded an ACE inhibitory rate of 77.58%. The M<sub>2</sub> component contained 18 types of amino acids, including seven types of essential amino acids with the highest proline content reaching 23.56% (<i>P</i> < 0.01). The molecular weight of the M<sub>2</sub> constituent was observed as 389 Da, with an amino acid sequence of Glu- Ser - Arg.</p>