【作者】 林向阳；

【导师】 阮榕生；

【作者基本信息】 南昌大学 ， 食品科学， 2006， 博士

【摘要】 水分在面团以及相关产品如馒头、面包等中具有很重要的作用。面团的制作过程实际是一个水合的过程，面团的性质和品质极大的影响了最终产品面包的品质。面粉水合形成面团的过程受各种因素的影响，比如面粉的化学组成、添加剂以及搅拌方式等等。研究发现，影响面粉水合品质的不仅仅是水分的含量，而且水分与面粉中各种成分的结合方式也很重要。很多研究认为水分直接影响面制品的新鲜度，并提出焙烤产品的老化与淀粉回生度和玻璃态转变有很大关系。目前，对于面粉的水合和面制品的变质的机理，还有待于从分子水平上进一步探索。本研究的宗旨是开发新的分析手段，并用这些手段从分子水平上探讨水在面团制作和面制品货价寿命保藏方面的作用。了解了水的作用，开发新的技术来监测和控制水在面团和面制品中的特性和作用，从而获得质量更好的、货架寿命更长的产品。 本论文的目的是研究和开发核磁共振光谱(Nuclear Magnetic Resonance或NMR)和核磁共振成像(Magnetic Resonance Imaging或MRI)技术并用它们来研究面包制作过程水分的分布状态，以及面包在不同储藏条件下的物理化学特性的变化。NMR和MRI是一种完全非破坏的分析手段，它可直观地显示食品中水分活性状态分布和水分的分布与迁移，可用来研究食品的物理及化学特性以及相关的加工过程，如食品冷冻、干燥、胶凝、浸泡、储藏等。本文借助NMR及MRI技术，对与面包加工和储藏有关的过程进行了分析，旨在寻找准确、适用的研究方法，获取和建立有助于加工手段和产品开发的知识和理论。 论文研究的第一章节主要内容是检验和开发适用于食品研究的NMR和MRI脉冲序列。内容涉及SE(自旋回波)序列、CPMG序列和IR(反转恢复)序列，并利用以上序列测定了面团、月饼、面包和奶酪，这些分别代表了高水分、低水分、高油脂和高水分的食品，通过实验建立了不同样品在不同脉冲序列下的各种效果，并相应地得到了必要的相关实验参数。 第二部分主要内容是探讨面筋含量、含水量、添加物、搅拌与面团中水的状态之间的关系。水分状态的测定使用自旋-晶格和自旋-自旋弛豫时间(T1和T2)。通过对不同面筋含量面团形成过程的测定得到NMR自旋—自旋弛豫时间与面团搅拌期的关系，得到面团更多还原

【Abstract】 Water plays an important role in flour dough and the related products such as steamed bread and baked goods. Flour dough making is in fact a hydration process whose characteristics or quality have profound impact on the quality of the final products. Flour hydration is mainly a function of the chemical composition of the flour, additives, and mixing. Research has suggested not only the amount of water but how water molecules are associated with flour matrix determines the quality of hydration. Many research reports have shown that the water is directly related to the freshness of flour-based products. Starch retrogradation and glass transition have been proposed to be responsible for staling of baked goods. Both startch retrogradation and glass transition are closely related to water. However, there is a serious lack of understanding of molecular mechanisms involved in flour hydration and quality deterioration of flour-based products.The overall goal of the present study was to develop analytical techniques to study the role of water in dough making and flour based product shelf life at molecular levels. The rationale underlying the present study was that once the role of water is understood, new methods may be developed to manipulate the properties of water in dough and final products so that better quality and longer shelf life of flour products could be developed.The overall objective of my thesis was to develop Nuclear Magnetic Resonance (NMR) relaxometry and Magnetic Resonance Imaging (MRI) based techniques to study the state of water in bread making processes and the physiochemical properties of bread under different storage conditions. NMR and MRI are non-destructive method that can be used to study the physical and chemical properties of materials including foods and related processes such as freezing, drying, soaking, storage, etc. MRI allows direct and uninterrupted visualization of structures and spatial distribution of water and mobility of water in foods.The first specific research aim of present work was to evaluate and develop NMR and MRI pulse sequences suitable for studies important to the accomplishment of my research objective. The spin-echo (SE) pulse sequence, the Carr Purcell Meiboom Gill (CPMG) pulse sequence, the inverse recovery (IR) pulse sequency更多还原