Gluten fractions unevenly altered the digestion and physical properties of wheat starch‐lauric acid system under non‐alkaline/alkaline conditions

Abstract

SummaryThis research delved into the role of gluten fractions on digestion, physical properties and structure of wheat starch (WS)–lauric acid (LA) system under non‐alkaline/alkaline conditions. Results showed that gluten fractions decreased the digestion of WS with LA and gliadin had greater effect on the digestion of WS with LA under non‐alkaline/alkaline conditions than glutenin. Specifically, gliadin increased RS content of WS with LA by 70.99% and 84.89%, respectively, under non‐alkaline and alkaline conditions. The diminished in WS digestion caused by gluten fractions and LA ascribed to the decrease in swelling power and leaching of starch. Rapid viscosity analyser (RVA) demonstrated that gluten fractions were conducive to WS–LA and/or WS–LA–protein complexes formation and gliadin was more helpful to these complexes' formation than glutenin under non‐alkaline conditions. Additionally, gliadin had greater effect on the stability and short‐range ordered structure of WS with LA than glutenin. Addition of gliadin resulted in 6.79% and 13.33% of increase in short‐range orderliness compared with WS–LA system under non‐alkaline and alkaline conditions, respectively. Furthermore, gluten fractions had greater influence on the digestion of WS with LA under alkaline conditions than non‐alkaline conditions ascribed to the formation of WS–LA and/or WS–LA–protein complexes with low swelling power and high ordered structure under alkaline conditions. This study provided crucial information on the design of starchy foods with low digestion.