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

揭示不同植物来源的蜡质正淀粉和高直链淀粉在退火过程中影响淀粉链重排和无定形和结晶结构域内相互作用的因素

• 批准号: RGPIN-2016-04698
• 负责人: Hoover, disableRatnajothi
• 金额: $ 1.3万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631039
• 关键词: Unravelling; Factors; Influence; Starch; Chain

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.

天然淀粉不具有使它们理想地适用于食品中的应用的特性。因此，这些淀粉被化学改性以提高它们对高温加工、剪切和反复冻融的稳定性。提供物理改性的淀粉具有相当大的兴趣，因为不使用化学试剂，并且物理改性的淀粉可用于任何类型的食品应用中。退火（ANN）是一种物理改性技术，其通过在接近糊化起始温度的温度下将淀粉颗粒在过量水（> 65%w/w）中加热并保持指定的时间长度来进行。人工神经网络已被证明可以增加晶体稳定性，从而改变淀粉的性质。然而，在不同直链淀粉含量的淀粉中实现这些变化的机制知之甚少。在此背景下，拟议的研究旨在了解在类似条件下进行人工神经网络的上述淀粉的无定形和结晶区域内发生的结构变化。短期目标：1）确定支链淀粉链的内部组织的影响（淀粉的主要结晶组分）对人工神经网络诱导的结晶层内结构变化的影响，2）探索在无定形区域内发生的结构变化（直链淀粉和一些支链淀粉分支点存在于这些区域中），3）确定非晶区对人工神经网络中晶区变化的贡献。4）了解人工神经网络对淀粉性质的影响。长期目标：1）通过选择性水解无定形区域，然后通过ANN和通过双重改性技术（其中ANN与其它物理和/或化学改性技术组合）来产生具有改进的物理化学性质的新型淀粉，和2）确定在其它增塑剂（甘油、丙二醇、山梨糖醇）存在下ANN是否能够将淀粉结构改性到与水相同的程度。新奇-拟议的研究是原始的，创新的，并将增加新的知识，人工神经网络的机制方面的结构变化，在所有级别的颗粒组织在淀粉中变化很大的直链淀粉含量。它还将解释ANN上淀粉结构的变化如何影响酶水解的速率和程度，对化学修饰中使用的试剂的反应性，脂质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人工神经网络协议来调整未充分利用的谷物，豆类和块茎淀粉的结构，达到化学修饰的水平。