Study Of Bread During Processing And Storage Using NMR And MRI Techniques

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...