Spray‐Dried Wheat Gluten Protein Hydrolysate Microcapsules: Physicochemical Properties, Retention of Antioxidant Capability, and Release Behavior Under Simulated Gastrointestinal Digestion Conditions

Wheat gluten is a by-product of the wheat starch industry, rich in bioactive peptides. Spray drying is an effective method for improving the stability of bioactive compounds. So, the aim of this study was to produce gluten hydrolysate by different proteases (alcalase, pancreatin, and trypsin) at different times (40-200 min). The hydrolysate with the strongest antioxidant potential (produced by pancreatin after 200 min of hydrolysis) was encapsulated by spray drying. The effect of wall material's type (maltodextrin, potato starch, and their combination at different ratios) on the encapsulation efficiency, physicochemical properties (moisture content, solubility, water activity, tapped and bulk density, and hygroscopicity), release behavior under simulated gastrointestinal digestion conditions, and morphology of microcapsules were evaluated. The microcapsules produced by maltodextrin and potato starch at a 30:70 ratio possessed the highest water activity (0.36), encapsulation efficiency (85.79%), and moisture content (8.2%). An increase in maltodextrin concentration increased the solubility, bulk, and tapped density. SEM images showed that microparticles were spherical with wrinkled surfaces. The microcapsules showed higher stability than free gluten hydrolysate. The combination of maltodextrin and potato starch at a 30:70 ratio could control the release of gluten hydrolysate under simulated gastrointestinal conditions. As a result, the use of maltodextrin and potato starch carriers at a 30:70 ratio in spray drying could effectively protect the bioactive properties of gluten hydrolysate and control its release.