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..

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

Ripening of banana fruit monitored by water relaxation and diffusion H-1-NMR measurements

Water transverse relaxation times T2 and self-diffusion coefficients D have been measured on banana samples at different ripening stages. Relaxation data have been interpreted on the basis of a chemical and diffusive exchange,model proposed by Belton and Hills [Mol. Phys. 61(4) (1987) 999] and Hills et al. [Mol. Phys. 67(4) (1989) 903]. According to that model the observed increase of T-2 values of both cytoplasmatic and vactiolar water may be mainly attributed to the decrease of starch concentration during the ripening process. On the other hand, the observed water self-diffusion coefficient decrease is related to sugar accumulation as starch hydrolysis proceeds. At the early stages of ripening, the individual self-diffusion coefficient values of cytoplasmatic and vacuolar water differ from one another and have been calculated through the analysis of relaxation time-separated pulsed field gradient nuclear magnetic resonance experiments [J. Magn. Reson. A 112 (1995a) 237]. (C) 2004 Elsevier Ltd. All rights reserved

A proton NMR relaxation study of water dynamics in bovine serum albumin nanoparticles

Water dynamics and compartmentation in glutaraldehyde cross-linked bovine serum albumin nanoparticles have been investigated by an integrated nuclear magnetic resonance (NMR) protocol based on water relaxation times and self-diffusion coefficients measurements. Multi-exponentially of water relaxation curves has been accounted for according to a diffusive and chemical exchange model (see B. P. Hills, S. F. Takacs and P. S. Belton, Mol. Phys., 1989, 67(4), 903, and Mol. Phys., 1989, 67(4), 913; E. Brosio, M. Belotti and R. Gianferri, in Food Science and Technology: New Research, ed. L. V. Greco and M. N. Bruno, Nova Science Publishers, Hauppauge (NY), 2008) that made it possible to single out water molecules in the molecular spaces in the interior of albumin nanoparticles, in the meso-cavities formed by packed nanoparticles and in the meniscus on top of the nanoparticles suspension. A quantitative rationalization of T(2) values of water different components allowed morphological information to be acquired as for the size of water filled compartments, while self-diffusion coefficient measurements of water excess or fluxed packed nanoparticles suspensions are describers of transport properties of soft biomaterials. The paper reports an NMR approach that can be seen as a general and relevant method to characterize excess-water-swollen soft biomaterials

A low-resolution and high-resolution nuclear magnetic resonance integrated approach to investigate the physical structure and metabolic profile of Mozzarella di Bufala Campana cheese

A low-resolution and high-resolution nuclear magnetic resonance (NMR) protocol to characterise the traditional Italian cheese Mozzarella di Bufala Campana is reported. Low-resolution relaxometry was used for the study of the state and distribution of water in different structural elements of cheese resulting from the stretching process. High-resolution NMR allowed definition of the "chemical fingerprint", the cheese complex matrix profile of low molecular weight metabolites extracted from Mozzarella. Both low-resolution and high-resolution NMR seem to provide useful parameters that could be used for monitoring the evolution of PDO (protected destination of origin) Mozzarella di Bufala Campana cheese. (c) 2006 Elsevier Ltd. All rights reserved