Starch characteristics and baking quality of chilled ready-to-eat sandwich bread made with starch branching enzyme II mutant wheat flour

Suitability of high-amylose starch branching enzyme II (sbeII) flour for industrial processing of wheat convenience foods (i.e., ready-to-eat chilled sandwich bread) is not known, specifically its impacts on bread quality and starch digestibility over chilled storage. Here we evaluated sbeII wheat quality in an industrial pilot plant using Chorleywood bread processing. Industrially-made sbeII bread showed lower volume upon production, and after chilled storage had lower starch digestibility (∼4% difference of starch digested at 90 min) and more resilient crumb texture compared to a wildtype (WT) control. sbeII breads made in a laboratory scale using an optimised AACC method also showed lower starch digestibility when analysed fresh and after chilled storage. Short-range molecular orderring (an indicator of starch crystallinity measured by 13C solid-state NMR) was lower for both fresh and stored bread, which suggested that the enzyme-resistant structures in sbeII bread were independent of starch retrogradation induced by storage.