Physicochemical, antibacterial and bio-functional properties of persian poppy-pollen (Papaver bracteatum) protein and peptides

In the present study, the effects of enzymatic hydrolysis with different proteases (Alcalase, pancreatin, pepsin and trypsin) on the composition of amino acids, nutritional value, techno-functional properties as well as antioxidant and antibacterial activities of poppy-pollen protein were investigated. The results showed that, the degree of hydrolysis (DH, 37.7–46.5%) and the composition of hydrophobic (~ 42%) and antioxidants (~ 21%) amino acids were influenced by the type of enzymes. The amount of essential amino acids (47–50%) and protein efficiency ratio (PER (~ 1.9) indicated the high nutritional quality and digestibility of peptides. Also, enzymatic hydrolysis led to the improvement of techno-functional (solubility, emulsification and foaming properties) properties of protein, especially in acidic conditions. However, peptides with high DH and low molecular weights had lower water (WHC) and oil (OHC) holding capacity. The highest scavenging of free radicals DPPH (75.6%), ABTS (92.7%), hydroxyl (69.4%), reducing power (1.37), nitric-oxide (30.6%), total antioxidant (1.24) and chelation Fe²⁺ (65.6%) and Cu²⁺ (25.4%) were affected by enzyme type and amino acids (AAs) composition. The highest inhibition of the growth of Escherichia coli (~ 15.7 mm) and Bacillus cereus (~ 14.6 mm) was related to peptides produced with pepsin and trypsin, respectively. The results of this research indicate the high potential of poppy-pollen peptides as a source of nutrients, functional, antioxidant, stabilizer and natural preservative for food and nutritional applications.