Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
Food Chem. 2020 Aug 1;320:126609. doi: 10.1016/j.foodchem.2020.126609. Epub 2020 Mar 13.
Bread crumb firming is largely determined by the properties of gluten and starch, and the transformations they undergo during bread making and storage. Amylose (AM) and amylopectin (AP) functionality in fresh and stored bread was investigated with NMR relaxometry. Bread was prepared from flours containing normal and atypical starches, e.g., flour from wheat line 5-5, with or without the inclusion of Bacillus stearothermophilus α-amylase. Initial crumb firmness increased with higher levels of AM or shorter AM chains. Both less extended AM and gluten networks and too rigid AM networks led to low crumb resilience. AP retrogradation during storage increased when crumb contained more AP or longer AP branch chains. Shorter AP branch chains, which were present at higher levels in 5-5 than in regular bread, were less prone to retrogradation, thereby limiting gluten network dehydration due to gluten to starch moisture migration. Correspondingly, crumb firming in 5-5 bread was restricted.
面包屑的紧实度在很大程度上取决于面筋和淀粉的特性，以及它们在面包制作和储存过程中发生的变化。利用 NMR 弛豫度研究了新鲜和储存面包中直链淀粉（AM）和支链淀粉（AP）的功能。面包是用含有正常和异常淀粉的面粉制备的，例如，来自小麦系 5-5 的面粉，或包含嗜热脂肪芽孢杆菌α-淀粉酶。初始面包屑的硬度随 AM 水平的提高或 AM 链变短而增加。AM 网络不够延展和过于刚性都会导致面包屑的弹性差。储存过程中，当面包屑中含有更多的 AP 或更长的 AP 支链时，AP 会发生回生。在 5-5 面包中含量较高的较短的 AP 支链不易发生回生，从而限制了由于面筋向淀粉迁移导致的面筋网络脱水。相应地，5-5 面包的面包屑紧实度受到限制。
