Food production molecular structures

NMR spectroscopy is one of the most widely used analytical tools for the study of molecular structure and dynamics. Spin relaxation and diffusion have been used to characterize protein dynamics [1, 2], polymer systems[3, 4], porous media [5-8], and heterogeneous fluids such as crude oils [9-12]. There has been a growing body of work to extend NMR to other areas of applications, such as material science [13] and the petroleum industry [11, 14—16]. NMR and MRI have been used extensively for research in food science and in production quality control [17-20]. For example, NMR is used to determine moisture content and solid fat fraction [20]. Multi-component analysis techniques, such as chemometrics as used by Brown et al. [21], are often employed to distinguish the components, e.g., oil and water. 

An interesting and important example of an animal poison is paralytic shellfish poison (PSP). This chemical, which is also known as saxitoxin and by several other names as well, is found in certain shellfish. But it is not produced by shellfish it is rather a metabolic product of certain marine microorganisms (Protista). These microorganisms are ingested by the shellfish as food, and their poison can remain behind in the shellfish s tissue. Paralytic shellfish poison is not a protein, but a highly complex organic chemical of most unusual molecular structure. 

Tlie demand for reliable, sensitive, automated, fast, low-cost methods for residue analysis that are also applicable to a wide range of drugs and matrices is growing fast, especially in the field of food inspection. A universal analytical scheme that could simultaneously quantify all compounds of interest in the edible animal products, correctly identify the molecular structure of the analytes, and, at the same time, produce very few false-negative and -positive results to protect the consumer, producer and international trade, would provide the most desirable approach. A unified procedure would eliminate the need for using separate multiresidue methods to screen food commodities for potential drug residues, and combinations of suitable single- or multianalyte methods to identify and quantify residues of individual analytes. 

Milk proteins are subdivided into random coiled caseins, which can be precipitated by acidification of raw skim milk to pH 4.6 at 20°C, and into more globular whey proteins, which remain in the serum after precipitation of the caseins (42). In Table 8, an overview is given of the molecular structure and basic properties of the major protein fractions present in milk. Some specific properties that might be of importance for their determination in foods and food products are also listed. For the young of mammals, including humans, milk is the first and, for most, the only food ingested for a considerable period of time. With the domestication of animals, it became possible to include milk in the diet of adult humans as well. For much of the world, particularly in the West, milk from cattle (Bos taurus) accounts for nearly all the milk processed for human consumption (43). 

Quality of a food product is related to its sensorial (shape, size, color) and mechanical (texture) characteristics. These features are strongly affected by the food structural organization (Stanley, 1987) that, according to Fardet et al. (1998), can be studied at molecular, microscopic, and macroscopic levels. In particular, micro structure and interactions of components, such as protein, starch, and fat, determine the texture of a food that could be defined as the external manifestation of this structure (Allan-Wojtas et al., 2001). 

Sensorial and mechanical characteristics of food products are strongly affected by the food structural organization that can be studied at molecular, microscopic, and macroscopic levels. 

The following sections focus on the description of the state and phase transition behavior of starch systems, as schematically illustrated in Figure 8.5, with an emphasis on their molecular organization and their response to various environments (temperature, solvent, other co-solutes, etc.). Selected material properties are also discussed in an effort to demonstrate structure-function relationships of this biopolymer mixture in pure systems and in real food products. 

In processed foods, non-enzymic browning reaction is the major source of its desirable flavors. Flavors of the products of this reaction depend upon the molecular structure of nitrogenous compounds (amines, amino acids, peptides, glycopeptides, proteins,... 

Dufour, E. (2002). Examination of the molecular structure of food products using front-face fluorescence spectroscopy. American Laboratory, 34, 51-55. 

The rate of migration of low molecular weight residual molecules from plastics into foods and interactions of the plastics with food components or other filled products depends on the molecular structure and the macroscopic (aggregate) nature of the plastic material. In order to perform useful estimations of mass transfers, for example from plastics to food, a basic knowledge of the structure of the plastic and food components and their influences on this phenomenon is necessary. 

The ultimate goal of all researchers in this area has been to relate precisely the macroscopic manifestations of protein functionality in its utilization with its molecular properties. Great progress recently has been made in relating particular molecular structure to enzymatic activity. However, in the area of food functionality, the advance has been less rapid. The obvious difficulties are attributable to the mixed nature of food systems. The macroscopic manifestation in these products is usually the result of many interactions between different proteins and between these and nonprotein components. The multiplicity of the reactions under the conditions of food preparation or processing bears little resemblance to the clean-cut, precise reactions of pure proteins in solution. All extrapolations from the latter to the former have met with little success. In absence of this direct approach, we have resorted to various indirect approaches. 

We note from all this prior work that structure at the macro, micro, nano and molecular levels of organisation will all be important. Secondly, the properties of the composite food product will not be related simply to a list of its components (the recipe), since different structural forms can be assembled from the same components by different processes. Emphasis on structure and its origin discriminates food materials science from the former descriptive approach of formulation/process empiricism embodied in most recipes. 

Polymer materials that are used to contain food are required to be resistant to shock and gas pressure. The physical properties of the final product depend largely on the details of the manufacturing process. By probing the variation of molecular structure in the container wall, C. Martin and co-workers (Keele, UK) have been able to provide a connection between the local order of the polymers and the manufacturing process. (Figure 3(a).)... 

Cellulose is the most abundant organic material found in nature (13). It is the primary component of plant cell walls and is therefore a large constituent of fruits and vegetables. Since cellulose is safe for human consumption, it is commonly used as an additive in food products. Cellulose and chemical derivatives of cellulose are also widely used as excipients in pharmaceutical applications. The biocompatibility of cellulose coupled with a molecular structure that is conducive to chemical modification, has made cellulose a staple of pharmaceutical formulations. Each anhydroglucose unit of the cellulose backbone contains three hydroxyl groups that provide reactive sites for chemical substitution. Thereby, cellulose can be chemically modified in a variety of ways to yield materials with differing properties useful for diverse pharmaceutical applications. 

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