Optimization of preparation process of buffalo milk active peptides microspheres by piercing method and in vitro releasing behavior of the microcapsules

In order to reduce the decomposition of the antioxidant peptide in the gastrointestinal tract and to have a sustained release behavior, encapsulated buffalo milk antioxidant peptides were prepared by piercing method using sodium alginate and chitosan as the shell. Based on peptides loading efficacy, and determined by one-factor experimental results, operating parameters as sodium alginate concentration, chitosan concentration and calcium chloride concentration were optimized by response surface methodology.The prepared microspheres were subjected by scanning electron microscopy and researched on its in vitro releasing behavior.The results showed that the optimal operating parameters were 1.28%, 1.51%, and 2.20% ( w/v) for sodium alginate concentration, chitosan concentration and calcium chloride, respectively. Upon the optimal conditions, the experiment led to an encapsulated efficacy of 95.20%. Scanning electron microscopy showed that the alginate-chitosan microcapsules had compact structure.The in vitro release studies showed that the release rate was only 7.98% in the simulated gastric buffer ( pH = 2.0) , and 89.41% in simulated intestinal buffer ( p H = 6.8) . It showed that the sample had an acid-resistant and good slow-release behavior in simulated intestinal buffer. These results conclusively suggested that encapsulated buffalo mike antioxidant peptides by this process can protect the peptides, and improve its stability, acid resistance and sustained release behavior.