Food complex

Autotroph An organism that can synthesize its own food—complex organic compounds— using simple inorganic sources, such as carbon dioxide... 

Colouring matter (food) Complex stability constants Concanavelin A Copper... 

Lipid peroxi tion of the membranes and fats plays an important role in the production of these aldehydes in cooked foods. Complex chemical and physical processes such as cooking can cause fat and lipid deterioration in which the nutritional and toxicologic values of the food may be affected. Formaldehyde is... 

The per capita consumption of rice in the United States has doubled since 1960 to approximately 10 kg in 1989. Over the last decade U.S. rice consumption has benefited from a growing trend in U.S. diets away from high fat animal products and toward grain-based foods. Many health groups encourage use of the complex carbohydrates found in grain products such as rice. Also, increases in the Asian and Hispanic segments of the U.S. 

Ethanol. Accurate projections of ethanol costs are much more difficult to make than are those for methanol. Large scale ethanol production would impact upon food costs and have important environmental consequences that are rarely cost-analyzed because of the complexity. Furthermore, for corn, the most likely large-scale feedstock, ethanol costs are strongly influenced by the credit assigned to the protein by-product remaining after the starch has been removed and converted to ethanol. 

Gums and starches were used in early attempts to replace the viscosity and lubricity of oils in foods. These were not well received by consumers because they assumed fats merely suppHed mouthfeel and a bit of flavor. On closer examination, it became evident that fats in food and in the diet performed many roles, some simple, some extremely complex, some understood, and some not understood. 

The complexity of total replacement has slowed the rate of introduction of new materials, but most ingredient producers introduce a product which replaces one or two aspects of fat functionahty and has already been cleared for use in foods by the FDA. 

The aroma of fmit, the taste of candy, and the texture of bread are examples of flavor perception. In each case, physical and chemical stmctures ia these foods stimulate receptors ia the nose and mouth. Impulses from these receptors are then processed iato perceptions of flavor by the brain. Attention, emotion, memory, cognition, and other brain functions combine with these perceptions to cause behavior, eg, a sense of pleasure, a memory, an idea, a fantasy, a purchase. These are psychological processes and as such have all the complexities of the human mind. Flavor characterization attempts to define what causes flavor and to determine if human response to flavor can be predicted. The ways ia which simple flavor active substances, flavorants, produce perceptions are described both ia terms of the physiology, ie, transduction, and psychophysics, ie, dose-response relationships, of flavor (1,2). Progress has been made ia understanding how perceptions of simple flavorants are processed iato hedonic behavior, ie, degree of liking, or concept formation, eg, crispy or umami (savory) (3,4). However, it is unclear how complex mixtures of flavorants are perceived or what behavior they cause. Flavor characterization involves the chemical measurement of iadividual flavorants and the use of sensory tests to determine their impact on behavior. 

A persistent idea is that there is a very small number of flavor quaUties or characteristics, called primaries, each detected by a different kind of receptor site in the sensory organ. It is thought that each of these primary sites can be excited independently but that some chemicals can react with more than one site producing the perception of several flavor quaUties simultaneously (12). Sweet, sour, salty, bitter, and umami quaUties are generally accepted as five of the primaries for taste sucrose, hydrochloric acid, sodium chloride, quinine, and glutamate, respectively, are compounds that have these primary tastes. Sucrose is only sweet, quinine is only bitter, etc saccharin, however, is slightly bitter as well as sweet and its Stevens law exponent is 0.8, between that for purely sweet (1.5) and purely bitter (0.6) compounds (34). There is evidence that all compounds with the same primary taste characteristic have the same psychophysical exponent even though they may have different threshold values (24). The flavor of a complex food can be described as a combination of a smaller number of flavor primaries, each with an associated intensity. A flavor may be described as a vector in which the primaries make up the coordinates of the flavor space. 

Two classes of fat replacers exist mimetics, which are compounds that help replace the mouthfeel of fats but caimot substitute for fat on a weight for weight basis and substitutes, compounds having physical and thermal properties similar to those of fat, that can theoretically replace fat in all appHcations (46). Because fats play a complex role in so many food appHcations, one fat replacer is often not a satisfactory substitute. Thus a systems approach to fat replacement, which reHes on a combination of emulsifiers, gums, and thickeners, is often used. 

Food processing operations can be optimi2ed according to the principles used for other chemical processes if the composition, thermophysical properties, and stmcture of the food is known. However, the complex chemical composition and physical stmctures of most foods can make process optimi2ation difficult. Moreover, the quaUty of a processed product may depend more on consumer sensory responses than on measurable chemical or physical attributes. 

The extension of the useful storage life of plant and animal products beyond a few days at room temperature presents a series of complex biochemical, physical, microbial, and economic challenges. Respiratory enzyme systems and other enzymes ia these foods continue to function. Their reaction products can cause off-davors, darkening, and softening. Microbes contaminating the surface of plants or animals can grow ia cell exudates produced by bmises, peeling, or size reduction. Fresh plant and animal tissue can be contaminated by odors, dust, iasects, rodents, and microbes. 

Each food or food ingredient shows a characteristic equiHbrium relative humidity at a given moisture content and temperature. Thus as a food is dried and its moisture content is reduced from its fresh value where water activity is generally 1.0, to lower and lower values, the equiHbrium water activity of the food decreases as a complex function of residual moisture. The shape of the equiHbrium relative humidity—moisture content curve is set by the chemistry of the food. Foods high ia fmctose, for example, biad water and thus show lower water activities at high moisture contents. Dried pmnes and raisias are examples. Drying can be terminated at any desired moisture content and hence any water activity. 

Phytic acid (9), although restricted to a more narrow range of food products, mainly grains, complexes a broader spectmm of minerals than does oxahc acid. Decreased availabiUty of P is probably the most widely recognized result of excessive iatakes of phytic acid, yet Ca, Cu, Zn, Fe, and Mn are also complexed and rendered unavailable by this compound (47—49). Phytic acid has also been reported to reduce the activity of a-amylase and to decrease the activity of both proteolytic and Hpolytic enzymes (50). 

Mycotoxins. The condition produced by the consumption of moldy foods containing toxic material is referred to as mycotoxicosis. Molds and fungi fall iato this category and several derive thek toxicity from the production of oxaflc acid, although the majority of mycotoxias are much more complex. 

Hair Coloring Regulation Issues. In the United States the classification of color additives is complex. Under the Federal Food, Dmg and Cosmetic Act, all cosmetic colors must be the subject of an approved color additive petition to the Food and Dmg Administration there is an exception for coal-tar colorants used to color hair. Based on the composition of these colorants, FDA can require a certification on each manufactured batch of colorant to assure conformance with the approved specifications. In the early 1990s FDA has required certification only for synthetically derived coal-tar type colors. Many of the approved color additives, both certified and noncertified, are restricted ia their potential use. These restrictions can be found ia the color additive regulations ia the Code of Federal Regulations at 21 CFR 73 and 74. 

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