Unravelling the Factors that Influence Starch Chain Realignment and Interactions Within the Amorphous and Crystalline Domains of Waxy Normal and High Amylose Starches of Different Botanical Origins on Annealing

本土淀粉没有使它们非常适合应用于食品的特性。因此，对这些淀粉进行化学改性，以提高其对高温加工、剪切和反复冻结和解冻的稳定性。人们对提供物理改性的淀粉很感兴趣，因为不使用化学试剂，并且物理改性的淀粉可以用于任何类型的食品应用。退火(ANN)是一种物理改性技术，它通过在接近糊化起始温度的温度下，将淀粉颗粒在过量水(&gt；65%w/w)中加热并保持特定的时间长度来进行。人工神经网络已被证明可以提高结晶稳定性，导致淀粉性质的变化。然而，在不同直链淀粉含量的淀粉中实现这些变化的机制还知之甚少。在此背景下，本研究旨在了解在相似条件下，上述淀粉的无定形和结晶区的结构变化。短期目标：1)确定支链淀粉链(淀粉的主要结晶成分)的内部结构对人工神经网络诱导的结晶片层内结构变化的影响；2)探讨非晶区内发生的结构变化(这些区域中存在直链淀粉和一些支链淀粉支点)对神经网络的影响；3)确定非晶区对人工神经网络结晶区内变化的贡献；4)了解神经网络对淀粉性质的影响。长期目标：1)通过选择性地水解无定形区域，然后采用ANN和双重改性技术，其中ANN与其他物理和/或化学改性技术相结合，创建具有改进的物理化学性质的新型淀粉，以及2)确定在其他增塑剂(甘油、丙二醇、山梨醇)存在的情况下，ANN是否能够像水一样改变淀粉的结构。新颖性-拟议的研究具有原创性和创新性，并将为人工神经网络的机制增加新的知识，涉及直链淀粉含量变化很大的淀粉中各级颗粒组织的结构变化。它还将解释人工神经网络上淀粉结构的变化如何影响酶水解的速度和程度、对化学修饰所用试剂的反应性、脂络合能力和结晶稳定性。意义-从这项研究中获得的知识将使食品加工商能够通过使用不同的ANN协议来定制未得到充分利用的谷物、豆类和块茎淀粉的结构，达到化学修饰所达到的水平。

Native starches do not have properties that make them ideally suited for applications in food products. Consequently, these starches are modified chemically to improve their stability to high temperature processing, shear, and repeated freezing and thawing. There is considerable interest in providing starches that are physically modified because no chemical reagents are used, and the physically modified starch can be used in any type of food application. Annealing (ANN) is a physical modification technique that is carried out by heating and holding starch granules in excess water (>65% w/w) for a specified length of time at a temperature close to the onset temperature of gelatinization. ANN has been shown to increase crystalline stability resulting in changes to starch properties. However, the mechanism by which these changes are achieved in starches of different amylose content is poorly understood. Against this background, the proposed research aims to understand the structural changes that occur within the amorphous and crystalline regions of the above starches subjected to ANN under similar conditions. Short term objectives: 1) To determine the influence of the internal organization of amylopectin chains (the main crystalline component of starch) on ANN induced structural changes within the crystalline lamellae, 2) To explore the structural changes that occur within the amorphous regions (amylose and some amylopectin branch points are present in these regions) on ANN, 3) To determine the contribution of amorphous regions to changes within the crystalline regions on ANN, 4) To understand the influence of ANN on starch properties. Long term objectives: 1) To create novel starches with improved physicochemical properties by selectively hydrolysing amorphous regions followed by ANN and by dual modification techniques in which ANN is combined with other physical and/or chemical modification techniques, and 2) To determine whether ANN in the presence of other plasticizers (glycerol, propylene glycol, sorbitol) are able to modify starch structure to the same extent as water. Novelty - The proposed research is original, innovative and will add new knowledge to the mechanism of ANN with respect to the structural changes at all levels of granule organization in starches varying widely in amylose content. It will also explain how changes to starch structure on ANN impacts the rate and extent of enzyme hydrolysis, reactivity towards reagents used in chemical modification, lipid complexing ability and crystalline stability. Significance - The knowledge gained from this study would enable food processors to tailor the structure of under-utilized cereal, pulse and tuber starches by using different ANN protocols to a level met by chemical modification.