Porcine Blood: An Eco-Efficient Source of Multifunctional Protein Hydrolysates

Porcine blood is a major slaughterhouse by-product and a sustainable source of high-quality proteins with potential food and nutraceutical applications. This study valorized porcine whole blood (WB, 6.7 ± 0.1% protein) and red cell fraction (CF, 50.4 ± 0.2% protein) through alcalase hydrolysis, generating hydrolysates (WBH and CFH) with bioactive and techno-functional properties. Optimal hydrolysis conditions, defined as enzyme-to-substrate (E/S) and incubation time yielding the highest degree of hydrolysis (DH) with cost-effective enzyme usage, were 1% E/S for 4 h (WBH) and 2.5% E/S for 4 h (CFH). WBH showed a higher DH (59.5 ± 2.6%) than CFH (30.8 ± 3.3%). Antioxidant assays revealed higher ABTS activity in CFH (14.1 vs. 11.1 mg ascorbic acid equivalents/g, p < 0.05), while both exhibited similar ORAC values (166.8-180.2 mg Trolox equivalents/g, p > 0.05). After simulated gastrointestinal digestion, ABTS activity was preserved, whereas ORAC decreased (~40%). ACE inhibitory activity was also pronounced, particularly in CFH (IC₅₀ = 59.5 µg protein/mL), but digestion converged values between hydrolysates (118-135 µg protein/mL). Techno-functional tests showed moderate emulsifying activity (~40%), with CFH displaying markedly higher oil absorption (4.79 vs. 1.31 g oil/g). Considering the limited information on porcine blood hydrolysates under gastrointestinal conditions, these findings provide new insights into their stability and support their potential as multifunctional ingredients for health-promoting foods and functional formulations.