Hydrolysis of soft wheat flour: Enhanced functional properties and the effect of starch on allergenicity reduction

Abstract

The possibility to utilize Alcalase to hydrolyze soft wheat flour (SWF) containing high concentration of solids (i.e. starch) and the effect of its presence was investigated. At a degree of hydrolysis of 23.49% +/- 0.64%, sample prepared as 15% (w/w) showed greatest reduction in gliadin content, resulting in 9.42 +/- 1.5 ppm of gluten, tested by competitive ELISA test. SDS-PAGE electrophoresis confirmed the differences in gliadin content for all of the prepared wheat flour hydrolysates (WFHs). All WFHs had improved radical-scavenging (>60%), metal-ion chelating (>80%) and technofunctional properties after enzymatic hydrolysis compared to SWF. FTIR spectra confirmed structural changes in the Amide I (1,700-1,600 cm(-1)) region. Changes in total zeta-potential and average particle size were observed. The hydrolysis reaction was facilitated by the increase of the solids content since it interferes with the aggregation of gluten proteins, therefore less available water was proven beneficial for the enzymatic reaction. Novelty impact statement: Gluten originating from soft wheat flour can be efficiently hydrolyzed by endo-protease Alcalase (DH similar to 24%), without introducing steps that include the extraction and isolation of gluten. By preparing the wheat flour hydrolysates, the significant reduction of adverse allergenicity of wheat flour has been achieved; gluten content was less than 10 ppm. Improvement of techno-functional properties, zeta-potential and particle size distribution, as well as antioxidant potential of soft wheat flour was observed upon enzymatic hydrolysis for all samples.