Physical and chemical stability of microencapsulated okara protein hydrolysate by spray drying

Abstract

Microencapsulation is a process used for protecting substances that are susceptible to degradation or reduction of their functionality due to different reactions such as oxidation, hydrolysis, among others. This study aimed to evaluate the effect of microencapsulation, using maltodextrin or modified starch as wall materials, on the stability of okara protein hydrolysates. We analyzed the microstructure, antioxidant capacity, and color of the samples during powder storage for 120 days at 35 °C. Micrographs obtained by scanning electron microscopy indicated that the microencapsulation process favored the particles’ physical integrity. The color difference observed between the encapsulated and unencapsulated samples was probably due to the addition of wall materials that contributed to color change of the powder obtained by spray drying. The results indicated that the microcapsules obtained by spray drying using maltodextrin or modified starch maintained the powder color and showed good ability to sequester the free radical ABTS and content of reducing substances from the Folin-Ciocalteau reagent during storage.

Keywords:
Okara; Antioxidant capacity; Maltodextrin; Modified starch; Microstructure; Color