Improvement of the functional and antioxidant properties of rice protein by enzymatic hydrolysis for the microencapsulation of linseed oil

摘要

In this study, the potential use of rice protein hydrolysates as emulsifying and encapsulating agents in the microencapsulation of linseed oil by spray drying was evaluated. The proteases Alcalase and Flavourzyme were used to obtain protein hydrolysates with various degrees of hydrolysis from rice protein isolate. Linseed oil-in-water emulsions stabilized by maltodextrin and protein hydrolysates obtained by Alcalase or Flavourzyme were characterized by oil droplet size, zeta-potential, rheological behavior, emulsion stability, and emulsion capacity. The emulsions were spray dried and evaluated according to their encapsulation efficiency and lipid oxidation stability. The results showed that the emulsions stabilized by Flavourzyme protein hydrolysate presented smaller oil droplets and were more stable than Alcalase protein hydrolysate and rice protein isolate, resulting in high encapsulation efficiency (89.5%) for higher degree of hydrolysis. In contrast, microparticles containing Alcalase protein hydrolysate reduced the lipid oxidation of linseed oil during storage, due to higher antioxidant capacity of the protein hydrolysate.