Stability of the Meat protein type I collagen: Influence of pH, ionic strength, and phenolic antioxidant

The water-holding capacity (WHC) is among the key factors in determining the quality of meat and its value, which is strongly influenced by the content and quality of the connective tissue proteins like collagen. Therefore, the factors that influence the proteins' stability, e.g., pH, ionic strength, and the antioxidants which are used to increase the meat shelf-life, also affect the WHC. The interaction of collagen, whose structure is strongly influenced by the interaction with water molecules, can be studied following the behavior of water diffusion by low-resolution 1H NMR experiments. The present study is addressed to study the collagen stability as a function of pH, ionic strength, and phenolic antioxidants like catechin. The experimental study demonstrated how the 1H NMR time domain (TD) experiments are able to evaluate the hydration properties of collagen, not only as a function of ionic strength and pH, but also in determining the ability of catechin to interact both on the surface of the collagen fibrils and inside the fibrillar domain

NMR-Metabolic Methodology in the Study of GM Foods

The 1H-NMR methodology used in the study of genetically modified (GM) foods is discussed. Transgenic lettuce (Lactuca sativa cv "Luxor") over-expressing the ArabidopsisKNAT1 gene is presented as a case study. Twenty-two water-soluble metabolites (amino acids, organic acids, sugars) present in leaves of conventional and GM lettuce were monitored by NMR and quantified at two developmental stages. The NMR spectra did not reveal any difference in metabolite composition between the GM lettuce and the wild type counterpart. Statistical analyses of metabolite variables highlighted metabolism variation as a function of leaf development as well as the transgene. A main effect of the transgene was in altering sugar metabolism

Chapter 2. Low-resolution NMR – An analytical tool in foods characterization and traceability

BOOK PREFACE - Real foods, both those at nature disposal such one and deriving by a trasformation or conservation cycle, are extremely complex chemical-physical systems, which is why a wide range of investigative techniques is required to their study in order to obtain complementary and integrable information. Nuclear Magnetic Resonance (NMR) spectroscopy, due to its own non-invasive nature, is very suitable to investigate foods, furthermore NMR response being chacterized by a very high qualitative and quantitative information content. A cursory glance at the chapters list shows that the routine applications of different NMR techniques to various food classes have been described. In the following chapters, besides a brief description of NMR experiment basic principles (chapter 1), the different instrumental NMR techniques – low resolution NMR (chapter 2), high resolution NMR (chapters 3 and 4), solid state NMR (chapter 6), NMR imaging (v 7) – and their use in food characterization..

Chapter 8 - Prospects for NMR future: a brief note on portable NMR sensors

BOOK PREFACE - Real foods, both those at nature disposal such one and deriving by a trasformation or conservation cycle, are extremely complex chemical-physical systems, which is why a wide range of investigative techniques is required to their study in order to obtain complementary and integrable information. Nuclear Magnetic Resonance (NMR) spectroscopy, due to its own non-invasive nature, is very suitable to investigate foods, furthermore NMR response being chacterized by a very high qualitative and quantitative information content. A cursory glance at the chapters list shows that the routine applications of different NMR techniques to various food classes have been described. In the following chapters, besides a brief description of NMR experiment basic principles (chapter 1), the different instrumental NMR techniques – low resolution NMR (chapter 2), high resolution NMR (chapters 3 and 4), solid state NMR (chapter 6), NMR imaging (v 7) – and their use in food characterization..

Applications of NMR in Dairy Research

NMR is a robust analytical technique that has been employed to investigate the properties of many substances of agricultural relevance. NMR was first used to investigate the properties of milk in the 1950s and has since been employed in a wide range of studies; including properties analysis of specific milk proteins to metabolomics techniques used to monitor the health of dairy cows. In this brief review, we highlight the different uses of NMR in the dairy industry

Chapter 8: Diffusive and Chemical Exchange Model: Practical Hits to Investigate Water Dynamics in Foods

ABSTRACT: In the present paper it is reported a full description of the model of the magnetic site exchange, as well as of the relations that, in the different limit conditions, allow the analysis and the physical interpretation of the relaxation curves as measured for water protons in food systems. It will be hereafter demonstrated that a correct measurement and analysis of both the longitudinal and transversal relaxation curves are likely to provide information on the morphology, size and distribution of the diffusive domains, and also on the physical-chemical parameters of the exchange processes involved

Proton NMR relaxation study of swelling and gelatinisation process in rice starch-water samples

Proton transverse magnetization decay curves of rice flour starch-water samples were measured and analysed for the presence of four components in the relaxation curve. T-2 values were interpreted on the basis of the diffusive and chemical exchange model that provided evidence for extra granular bulk water and three more water populations whose relaxation rate is governed by diffusive and chemical exchange with starch components. The analysis of relaxation data provided information on dynamics of water molecules as well as on the size and dispersion of diffusive domains. Furthermore, by measuring solid to liquid ratio, transverse and longitudinal relaxation curves of starch-water mixtures at increasing temperatures - from 20 to 77 degrees C - swelling and gelatinisation processes were monitored