Food properties structural

M. Rinaudo in "Food hydrocolloids Structures, Properties and Functions" Edit. K. Nishinari, E. Doi, Plenum Press, NY (1994) 21. 

NMR is an incredibly versatile tool that can be used for a wide array of applications, including determination of molecular structure, monitoring of molecular dynamics, chemical analysis, and imaging. NMR has found broad application in the food science and food processing areas (Belton et al., 1993, 1995, 1999 Colquhoun and Goodfellow, 1994 Eads, 1999 Gil et al., 1996 Hills, 1998 O Brien, 1992 Schmidt et al., 1996 Webb et al., 1995, 2001). The ability of NMR to quantify food properties and their spatiotemporal variation in a nondestructive, noninvasive manner is especially useful. In turn, these properties can then be related to the safety, stability, and quality of a food (Eads, 1999). Because food materials are transparent to the radio frequency electromagnetic radiation required in an NMR experiment, NMR can be used to probe virtually any type of food sample, from liquids, such as beverages, oils, and broth, to semisolids, such as cheese, mayonnaise, and bread, to solids, such as flour, powdered drink mixes, and potato chips. 

In this level, the fundamental tasks required to convert the raw materials into the final product are identified. All tasks are related to property differences. Siirola (1996) has presented the following hierarchy of property differences molecular identity, amount, composition, phase, temperature/pressure, form. This list of tasks is not very well suited for food properties. Common tasks for food processes are decontamination (e.g. pasteurization and sterilization) and structure formation (e.g. emulsification, size reduction of dispersed phase in an emulsion, crystallization, interfacial adsorption/desorption). 

Among the heterocyclics there is one group which will be thoroughly examined the pyrazines. The compounds belonging to this family play a very important role as contributors of desirable food flavor properties. Structurally, pyrazines are heterocyclic nitrogen compounds and their formation is a quite complicated process. Maga and Sizer (4) present a summary of these formation pathways. 

Popineau, Y. and Pineau, F. 1993. Emulsifying properties of wheat gliadins and gliadin peptides In Food Proteins. Structure and Functionality (K.D. Schwenke and R. Mothes eds), pp. 290-296. VCH, Weinheim. 

Linear viscoelasticity is the simplest type of viscoelastic behavior, in which viscoelastic properties are independent of the magnitude of applied stress or strain (Barnes et al., 1989 Gunasekaran and Ak, 2002). Linear viscoelasticity is usually exhibited by food materials at very small strains (Rao, 1992) that cause negligible damage to the food s structure the phenomenon must therefore be investigated experimentally using small deformation test methods. 

The next area of future development is microstructure analysis. Although numerous attempts have been made to connect crystal stmcture to food texture, a long road still remains ahead before it can be said that a certain type of stmcture leads definitively to certain mechanical properties. Development of methodologies for structure analysis and further developments in analytical modeling of crystalline microstructure are needed. Further, the connection between these microstructural models and food properties related to the crystalline microstructure are important. 

Chapter 11 deals with methods and techniques used to examine the microstructure of foods. In trying to relate micro structure and food properties the main problem is selecting the relevant scale at which elements interact to produce a given behavior or... 

The measurement of rheological properties for non-Newtonian, lipid-based food systems, such as dilatant, pseudoplastic, and plastic, as depicted in Figure 4.1, are much more difficult. There are several measurement methods that may involve the ratio of shear stress and rate of shear, and also the relationship of stress to time under constant strain (i.e., relaxation) and the relationship of strain to time under constant stress (i.e., creep). In relaxation measurements, a material, by principle, is subjected to a sudden deformation, which is held constant and in many food systems structure, the stress will decay with time. The point at which the stress has decayed to some percentage of the original value is called the relaxation time. When the strain is removed at time tg, the stress returns to zero (Figure 4.8). In creep experi-... 

Sekiguchi S., Miura Y., Kaneko H., Nishimura S.I., Nishi N., Iwase M., Tokura S., Molecular weight dependency of antimicrobial activity by chitosan oligomers, in Food Hydrocolloids Structures, Properties and Functions, Eds. Nishinari K. and Doi E., Plenum Press, New York, 1993, pp. 71-76. 

Zhang M., Kohr E., Hirano S., 1991. Hydrogels of chitin and chitosan. In Nishinari K. and Doi E. (Eds.), Food Hydrocolloids Structure, Properties and Functions, pp. 65-70. New York Plenum Press. 

The main constituents just referred to are responsible for the physical properties (structure, texture, and color) as well as the flavor of foods. Sometimes, specific natural or synthetic ingredients (such as salt or antioxidants) are added to improve the food properties [1-3]. 

Maga, J.A., Lactones in foods, CRC Critical Rev. Food Technol. Nutr., 8, p. 1, 1976. Dufosse, L., A. Latrasse, H.E. Spinnler, Importance of lactones in food flavors structure, distribution, sensory properties and biosynthesis. Sciences des Alim., 14, 1, p. 17, 1994. 

E Dickinson. In K Nishinari, E Doi, eds. Food Hydrocolloids Structure Properties and Functions. New York Plenum Press, 1993, pp 387-399. 

The principal used in polymer-clay nanocomposites leads the individual clay layers as well as the polymer chains to function more effectively with numerous improved properties such as high moduli, increased strength and heat resistance, decreased gas permeability and flammability, increased biodegradability of biodegradable polymers, and attractive electrical properties when compared to virgin polymers or conventional micro- and macrocomposites [37]. These properties make them ideal materials for applications in food packaging, structural automotive components, and electronics among others. 

Uses Thickener, stabilizer, emulsifier, adhesive, and gellant in foods Properties Semifirm gel structure water-sol. vise. 4000 cps (2% aq.)... 

Sibutramine is also a mixed inhibitor of SERT and NAT but does not display any antidepressant properties. Instead, it is used in the management of obesity, following an observed reduction of food intake. Structurally, one can observe the substituent at the a-carbon, in this case an isobutyl group, which gives an amfetamine-type derivative. 

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