Stabilization and analysis of saffron-pollen peptides within coated-nanoparticles: Nutritional, antioxidant, antibacterial, ACE and DPP-IV inhibitory activities

In this study, the potential of saffron pollen (SP) and its proteins (SPP) as a novel source for the production of bioactive peptides (SPPHs) was evaluated. Also, the capacity of nanoliposomes (NLs) and chitosomes (NCs) in loading, stabilizing, and controlled release of SPPHs was investigated. SPP and proteolyzed samples (SPPHs) with different enzymes (pepsin, alcalase, trypsin and pancreatin), were rich in antioxidant (∼18-20%), hydrophobic (∼44.9-46.5%), essential (∼43.1-45.6%) amino acids, nutritional value and high digestibility (PER 2.36-2.58). Changes in the secondary structures and conformational properties of SPP as a result of proteolysis were confirmed by FTIR analysis. The antioxidant and antibacterial activities (inhibition of E. coli and B. cereus growth) of SPPHs were affected by the degree of hydrolysis (DH), protease type, and AAs composition. Also, saffron peptides showed antihypertensive (∼69.6%) and antidiabetic (∼49.2%) potential. Successful loading of the optimized peptide (SPPHs-Al) into NLs and NCs was achieved with stable physical properties, homogeneity, and high encapsulation efficiency (∼78%). The coating of particles and the localization of peptides within the monolayer membrane and the interior of vesicles were confirmed. Also, the aggregation and agglomeration of particles and leakage of loaded SPPHs under the influence of thermal stresses, freezing, or gastrointestinal digestion were minimized after membrane coating. Finally, NCs containing SPPHs can be considered as a novel source of bioactive compounds for nutritional and pharmaceutical purposes. • Saffron pollen peptides (SPPHs) exhibit high antioxidant, antibacterial, and bioactive properties. • Proteolysis alters SPP secondary structure, enhancing peptide nutritional value and digestibility. • Nanoliposomes and chitosomes efficiently encapsulate and stabilize saffron peptides with ∼78% efficiency. • Coated nanoparticles minimize peptide leakage and aggregation under thermal and digestive stresses. • SPPHs-loaded chitosomes showcase potential for antihypertensive (ACE) and antidiabetic (DPP-IV) therapeutic applications.