Valorization of Goat Blood: Hydrolysate Production, Identification, Stability, and Bioavailability upon Gastrointestinal Digestion of Peptides with Dual ACE and DPP-IV Inhibitory Properties

Goat blood, a major slaughterhouse by-product, was systematically valorized into dual-function bioactive peptides through an optimized four-step process. Four blood preparations—whole blood (HB), anticoagulant-treated blood (HBS), red blood corpuscles (BC), and plasma (PM)—were subjected to heat pretreatment (90 °C, 15 min) and enzymatic hydrolysis. Neutrase hydrolysis of heat-pretreated whole blood at 8% substrate concentration for 4 h (HBN-8) yielded optimal protein recovery (44.38%) with dual ACE (88.24%) and DPP-IV (81.13%) inhibition. Ultrafiltration enriched bioactive peptides in the ≤3 kDa fraction (DPP-IV: 87.8%; ACE: 65.5%). LC-MS/MS de novo sequencing identified 14 novel peptide sequences (4–9 amino acids), with the most potent SEC fraction showing IC50 values of 0.89 and 0.45 mg Leu eq./mL for DPP-IV and ACE inhibition, respectively. Critically, simulated gastrointestinal digestion enhanced rather than diminished bioactivity, with ACE inhibition increasing progressively to 60.91% at the intestinal phase, supported by predicted generation of bioactive fragments from parent sequences. Caco-2 assays confirmed peptide safety (100–1000 µg/mL) and demonstrated 10.47% transepithelial transport with retained dual inhibitory activities. This study establishes goat blood as a sustainable source of orally bioavailable, GI-stable peptides for the development of functional foods targeting hypertension and type 2 diabetes.