Use of carbohydrase to enhance protein extraction efficiency and antioxidative properties of oat bran protein hydrolysates

In this study, medium oat bran samples were treated with four cell wall carbohydrases degrading enzymes (viscozyme® L, α-amylase, amyloglucosidase, celluclast®). Their effects on protein extraction efficiency and, on antioxidant properties of obtained protein isolates and resulting alcalase hydrolysates were investigated. The results showed that sample pre-treated with amyloglucosidase (8 units/g) had the higher protein content (82%) while celluclast (5–60 endo-glucanase units (EGU)/g) pre-treated samples had protein content similar to that of control (54%). In the oxygen radical absorbance assay (ORAC) all samples of protein isolates had significantly higher peroxyl radical scavenging activity than the control. The sample pre-treated with alpha-amylase (2300 units/g) displayed the highest activity with an ORAC value of 165 ± 16 μM Trolox Equivalents (TE)/g. Proteins were hydrolyzed with alcalase and radical scavenging activities of hydrolysates assessed by ORAC and HO
• radical assays. Sample pre-treated with viscozyme 1.5 Fungal Beta-glucanase Units (FBU)/g was the more active in both assays: ORAC value 521 ± 53 μM TE/g and HO
• radical inhibition 26.3 ± 1.5%. A tandem mass spectrometric analysis of multiple charged ions within the hydrolysates allowed the identification of four new peptides.

► In this study, we used carbohydrases to enhance extraction of proteins.
► We found an increase of radical scavenging activity of proteins isolates.
► Alcalase hydrolysis also increase scavenging activity.
► Four novel peptides were identified by mass spectrometry.