Physicochemical and Functional Evaluation of Chia Mucilage (Salvia hispanica)–Alginate Microcapsules as a Delivery System of ACE-Inhibitory Peptides from Phaseolus lunatus

Biopolymers and bioactive peptides of plant origin represent sustainable resources with high potential for the development of functional ingredients with health benefits. An underutilized plant source of antihypertensive peptides is lima bean protein (<i>Phaseolus lunatus</i>); however, these peptides can be inactivated or degraded during their passage through the gastrointestinal tract. This study evaluated chia (<i>Salvia hispanica</i>) mucilage (CM) combined with sodium alginate (Al) as a hybrid encapsulation matrix for ACE-inhibitory peptides (<10 kDa) from <i>P. lunatus</i>. The ionic gelation technique was used, and encapsulation conditions were optimized using a 2³ factorial design that evaluated CM:Al ratios, calcium concentration, and hardening time. The optimal formulation (30:70 CM:Al; 0.05 M CaCl₂; 20 min of hardening time) achieved approximately 48% encapsulation efficiency and maintained the peptides' ACE-inhibitory (IC₅₀ mg/mL) activity during simulated gastric digestion with controlled intestinal release. The formed capsules demonstrated good flow properties, thermal stability up to 178 °C, and preserved ACE-I activity (0.1 mg/mL IC₅₀) significantly better than alginate alone after in vitro digestion. These findings suggest that CM:Al blends could produce capsules with the ability to protect bioactive peptides with low molecular weight, warranting further investigation through in vivo bioavailability studies and structural characterization to confirm the proposed matrix-enhancing mechanisms.