Revalorization of a peach (Prunus persica (L.) Batsch) byproduct: Extraction and characterization of ACE-inhibitory peptides from peach stones

The value-added use of peach stone for production of a high protein product was investigated. Different parameters were optimized in order to obtain the highest protein yield in the extraction of peach seed proteins. Optimal conditions enabled the extraction of 43 g of protein per 100 g of dried and defatted milled seeds. Different enzymes and parameters were also tried in order to obtain the highest hydrolysis degree in the digestion of this peach seed protein isolate. Thermolysin was the enzyme that yielded the extract with the highest ACE-inhibition capability. After ultrafiltration through different molecular weight cut-off filters, potential antihypertensive peptides remained in the fraction below 3 kDa. Three different peptides (LYSPH, LYTPH, and HLLP) resisting simulated gastrointestinal digestion and ACE activity and demonstrating antihypertensive in vitro capacity were identified by HPLC-MS/MS. This is the first time that potential antihypertensive peptides have been isolated from peach stones.