Nutritional derivatives

The successful and possibly rapid degradation of toxic dye residues is of considerable importance form both a human and a veterinary toxicological point of view and for environmental protection. Because of the high amount of dyes loaded in the environment, much effort has been devoted to the development of physical, physicochemical and microbiological methods obtaining the degradation of dyes to non-toxic (even nutritive) derivatives. As has been previously mentioned, visible spectroscopic methods are widely applied for the measurement of the decomposition rate of dyes. However, when more than one dye molecule is simultaneously present or the primary decomposition products also absorb on... 

After a period of relative neglect, nutrition as a medical science is now an area of great clinical and investigative activity, This renewed interest in clinical nutrition derives in large part from observations suggesting that early nutritional deprivation not only interferes with the maintenance of health, growth and resistance to disease but if present during critical periods of central nervous system development may also cause permanent impairment of intellectual capacity. 

Ingredients used in pet foods are usually high in nutritional quaHty but generally not desirable as human foods primarily because they do not conform to human taste or processing expectations. By-products such as rendered proteins and fat converted into pet foods may have a derivation unappealing to humans, yet after processing may actually be more free of microorganisms and toxins than foods consumed by humans. 

Derived plant and animal products make better use or upgrade the nutritional quaHty of already existing materials or products. Synthetic and manufactured products arose from knowledge of the functional properties of food ingredients and of human and animal nutrition that involved more precise definition of nutrient requirements for growth, reproduction, lactation, and body maintenance in both humans and domestic Hvestock. Pood products have been developed to meet human needs under abnormal environments, eg, military rations for arctic, tropical, or desert environments, and special products for astronauts ia space flights. 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

Proteins and Meals. Nutritional properties of the oilseed protein meals and their derived products are deterrnined by the amino acid compositions, content of biologically active proteins, and various nonprotein constituents found in the defatted meals. Phytic acid (3), present as salts in all four meals, is beheved to interfere with dietary absorption of minerals such as 2inc, calcium, and iron (67) (see Food toxicants, naturally occurring Mineral nutrients). ... 

Although riboflavin can be assayed more readily by chemical or microbiological methods than by animal methods, the latter are preferred for nutritional studies and as the basis of other techniques. Such assays depend upon a growth response the rat or chick is the preferred experimental animal. This method is particularly useful for assaying riboflavin derivatives, since the substituents frequently reduce or eliminate the biological activity. 

Wool, as a keratin, is a highly cross-linked, insoluble proteinaceous fiber, and few animals have developed the specialized digestive systems that aUow them to derive nutrition from the potential protein resource. In nature, these few keratin-digesting animals, principally the larvae of clothes moths and carpet beetles, perform a useful function in scavenging the keratinous parts of dead animals and animal debris (fur, skin, beak, claw, feathers) that ate inaccessible to other animals. It is only when these keratin-digesting animals attack processed wool goods that they are classified as pests. Very often they enter domestic or industrial huildings from natural habitats such as birds nests. 

Soybean Protein Isolates. Soybean protein isolates, having a protein content of >90 wt%, are the only vegetable proteins that are widely used in imitation dairy products (1). Most isolates are derived from isoelectric precipitation, so that the soybean protein isolates have properties that are similar to those of casein. They are insoluble at thek isoelectric point, have a relatively high proportion of hydrophobic amino acid residues, and are calcium-sensitive. They differ from casein in that they are heat-denaturable and thus heat-labile. The proteins have relatively good nutritional properties and have been increasingly used as a principal source of protein. A main deterrent to use has been the beany flavor associated with the product. Use is expected to increase in part because of lower cost as compared to caseinates. There has been much research to develop improved soybean protein isolates. 

In view of the well-documented inhibition of dihydrofolate reductase by aminopterin (325), methotrexate (326) and related compounds it is generally accepted that this inhibitory effect constitutes the primary metabolic action of folate analogues and results in a block in the conversion of folate and dihydrofolate (DHF) to THF and its derivatives. As a consequence of this block, tissues become deficient in the THF derivatives, and this deficiency has many consequences similar to those resulting from nutritional folate deficiency. The crucial effect, however, is a depression of thymidylate synthesis with a consequent failure in DNA synthesis and arrest of cell division that has lethal results in rapidly proliferating tissues such as intestinal mucosa and bone marrow (B-69MI21604, B-69MI21605). 

The isothiazole ring does not occur in nature. By far the most important synthetic isothiazole derivative is saccharin. This was the first non-carbohydrate sweetening agent to be discovered, as long ago as 1879. It is about 300 times as sweet as sucrose, and is still used in many countries as a non-nutritive sweetener. After it was found that administration of massive doses to rats caused bladder cancer, its use was banned in the New World, but the controversy continues as to whether there is any danger when it is used in small quantity. Saccharin is also used as an additive in electroplating processes (73AHC(15)233). 

One of the triumphs of the science of nutrition is the careful investigation that linked childhood rickets with vitamin D deficiency. This work, which led to methods for treating the disease, is too familiar to need repetition. A direct consequence of these efforts was the elucidation of the pivotal role played by vitamin D in calcium metabolism, as well as the structural studies that revealed that this compound (102) is in fact a steroid derivative. The past... 

Steinhour, W.D., Stokes, M.R., Clark, J.H., Rogers, J.A., Davis, C.L. and Nelson, D.R. 1982 Estimation of the proportion of non-ammonia-nitrogen reaching the lower gut of the ruminant derived from bacterial and protozoal nitrogen. British Journal of Nutrition 48 417-431. 

Humans can synthesize 12 of the 20 common amino acids from the amphiboHc intermediates of glycolysis and of the citric acid cycle (Table 28-1). While nutritionally nonessenrial, these 12 amino acids are not nonessential. AH 20 amino acids are biologically essential. Of the 12 nutritionally nonessential amino acids, nine are formed from amphibolic intermediates and three (cysteine, tyrosine and hydroxylysine) from nutritionally essential amino acids. Identification of the twelve amino acids that humans can synthesize rested primarily on data derived from feeding diets in which purified amino acids replaced protein. This chapter considers only the biosynthesis of the twelve amino acids that are synthesized in human tissues, not the other eight that are synthesized by plants. 

Tyrosine. Phenylalanine hydroxylase converts phenylalanine to tyrosine (Figure 28-10). Provided that the diet contains adequate nutritionally essential phenylalanine, tyrosine is nutritionally nonessential. But since the reaction is irreversible, dietary tyrosine cannot replace phenylalanine. Catalysis by this mixed-function oxygenase incorporates one atom of O2 into phenylalanine and reduces the other atom to water. Reducing power, provided as tetrahydrobiopterin, derives ultimately from NADPH. 

The carotenoids are the most widespread group of pigments in nature, with an estimated yield of 100 million tonnes per annum. They are present in all photosynthetic organisms and responsible for most of the yellow to red colours of fruits and flowers. The characteristic colours of many birds, insects and marine invertebrates are also due to the presence of carotenoids, which have originated in the diet. Animals are unable to synthesise carotenoids de novo, and so rely upon the diet as the source of these compounds. Carotenoids found in the human diet are primarily derived from crop plants, where the carotenoids are located in roots, leaves, shoots, seeds, fruit and flowers. To a lesser extent, carotenoids are also ingested from eggs, poultry and fish. Commercially, carotenoids are used as food colourants and in nutritional supplements (Table 13.1). Over recent years there has been considerable... 

Benchaar, C., Calsamiglia, S., Chaves, A. V., Fraser, G. R., Colombatto, D., McAllister, T. A., and Beauchemin, K. A. (2008). A review of plant-derived essential oils in ruminant nutrition and production. Anim. Feed Sci. Technol. 145,209-228. 

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