Starch structure and exchangeable protons contribute to reduced aging of high-amylose wheat bread

• Published in: Food chemistry 2022-08, Vol.385, p.132673-132673, Article 132673
• Main Authors: Li, Caili, Gidley, Michael J.
• Format: Article
• Language: English
• Subjects: 1H T2 NMR; Amylose - chemistry; Amylose content; Bread; Bread aging; Flour; High-amylose wheat; Protons; Resistant starch; Starch - chemistry; Texture; Triticum - chemistry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2022.132673

•High amylose wheat (HAW) bread has firmer structure than regular wheat bread.•HAW bread does not increase in firmness on storage up to 7 days unlike regular bread.•HAW bread has more rapid retrogradation due to amylose content and water mobility.•Resistant starch levels are much higher for HAW but unchanged on ageing for all breads. Breads were prepared from wild-type wheat flour (WTWF) and high-amylose wheat flour (HAWF) with amylose content (AM) 71% and 84%. Melting enthalpy of recrystallized amylopectin (ΔHAP) increased significantly on storage for wild-type (WT), slightly for 71% AM but not at all for bread with 84% AM. Firmness of bread was positively related to AM content and ΔHAP. Exchangeable proton populations and mobility in high-amylose wheat bread (HAWB) crumb were higher than WT bread measured by 1H T2 NMR, consistent with the higher water content needed to make doughs from HAWF leading to the crumb network being more plasticized and hindering crumb aging. Although starch recrystallization and bread firming increased, no increase in enzyme-resistant starch (RS) content was observed during bread aging, with RS content only dependent on AM content. Although HAWB has a harder crumb than wild-type, it has greater shelf-life stability and higher nutritional value.