Acids nutritive value improvement

The nutritional value of a proteia can be improved by the addition of amino acids of low abundance ia that proteia. Thus the fortification of plant proteias such as wheat, com, and soybean with L-lysiae, DL-methionine, or other essential amino acids (L-tryptophan and L-threonine) is expected to alleviate some food problems (11). Such fortification has been widespread ia the feedstuff of domestic animals. 

Pea.nuts, The proteins of peanuts are low in lysine, threonine, cystine plus methionine, and tryptophan when compared to the amino acid requirements for children but meet the requirements for adults (see Table 3). Peanut flour can be used to increase the nutritive value of cereals such as cornmeal but further improvement is noted by the addition of lysine (71). The trypsin inhibitor content of raw peanuts is about one-fifth that of raw soybeans, but this concentration is sufficient to cause hypertrophy (enlargement) of the pancreas in rats. The inhibitors of peanuts are largely inactivated by moist heat treatment (48). As for cottonseed, peanuts are prone to contamination by aflatoxin. FDA regulations limit aflatoxin levels of peanuts and meals to 100 ppb for breeding beef catde, breeding swine, or poultry 200 ppb for finishing swine 300 ppb for finishing beef catde 20 ppb for immature animals and dairy animals and 20 ppb for humans. 

In common with many other legume seeds, raw lentils contain some undesirable constituents, although the levels of these are not likely to be of concern in poultry feeding. Weder (1981) reported the presence of several protease inhibitors in lentils. Marquardt and Bell (1988) also identified lectins (hemagglutinins), phytic acid, saponins and tannins as potential problems but could find no evidence that these had adversely affected performance of pigs fed lentils. It is known that cooking improves the nutritive value of lentils for humans but the effects of consumption of raw lentils by non-ruminants have not been well documented (Castell, 1990). 

Primary structure of proteins can be chemically modified in order to improve their functional properties. This approach has been used with success to study the structure-function relationships (enzymatic function, biological function, physico-chemical and functional properties). Deliberate chemical modification of food proteins can result in alteration of the nutritive value, formation of potentially toxic amino acid derivatives, and contamination by toxic chemicals. 

Microbial transglutaminase is capable of incorporating amino acids or peptides covalently into proteins (Nonaka et al., 1996). This reaction can improve the nutritive values of food or feed proteins, because covalently incorporated amino acids or peptides behave like amino acid residues in a protein. 

Enzyme-catalyzed attachment of amino acids to proteins represents an attractive and interesting way for improving the nutritional value of food proteins. The enzymes that participate in the gastrointestinal digestion of food proteins catalyze exclusively hydrolytic reactions under physiological conditions. However the synthetic activity of proteolytic enzymes was reported first by Danilewski in 1886, and more recently a number of studies have been devoted to plastein formation from con-... 

Such chemical changes may lead to compounds that are not hydrolyzable by intestinal enzymes or to modifications of the peptide side chains that render certain amino acids unavailable. Mild heat treatments in the presence of water can significantly improve the protein s nutritional value in some cases. Sulfur-containing amino acids may become more available and certain antinutritional factors such as the trypsin inhibitors of soybeans may be deactivated. Excessive heat in the absence of water can be detrimental to protein quality for example, in fish proteins, tryptophan, arginine, methionine, and lysine may be damaged. A number of chemical reactions may take place during heat treatment including decomposition, dehydration of serine and threonine, loss of sulfur from cysteine, oxidation of cysteine and methio-... 

Most transgenic oilseeds with altered fatty acid composition remain research subjects, with commercial introduction limited to two crops, neither of which have yet achieved success in the marketplace. The expected benefits from transgenic crops with altered fatty acid composition include improved stability properties enhanced nutritive value expanded use of renewable resources to replace petroleum derived materials replacement of chemical processes, such as epoxidation of fatty acid double bonds and gradual expansion of agriculture as a chemical industry, a concept long ago known as chemurgy. It is possible to predict some issues that... 

Betapol , a human milkfat substitute produced by Loders Croklaan (Wormerveer, the Netherlands), is produced by interesterification of vegetable oils in which the component TAGs have been modified to more closely resemble those found in breast milk. This product closely mimics the specific structure and fatty acid composition of human milkfat and resembles breast milk in terms of its nutritional value and high content of palmitic acid at the sn-2 position than other milkfat substitutes. In addition, the use of Betapol in infant formula can lead to improved mineral and fat absorption and less calcium soap formation within the intestinal lumen resulting in softer stools. 

The problem with using plant sources of protein is that they do not provide the proper balance of the amino acids required for human nutrition [70]. Some of the deficient amino acids may be synthesized by the body. But some, the essential amino acids, must be acquired through the diet for proper human nutrition and growth. Commercial production of amino acids has mainly been for animal feed supplementation. However, cereals supplemented with synthetically produced essential amino acids could improve the nutritional value of plant crops to supply the human protein requirement. In this way a proportion of the crops now grown for animal feed could be diverted to human consumption, and more people could be fed from the same area of arable land than would be possible using animal protein. 

Legume seeds contain a number of antinutritive components, mainly lectin and trypsin inhibitors. The efficiency of the nutritional utilization of diets containing soybean is well below that expected on the basis of chemical composition [196]. In order to reduce the extent of this constraint, at present, all soy products go through expensive heat treatment or other processing procedures that can lead to losses of essential amino acids and to the production of toxic by-products. It is hoped that an effective strategy will help improve the nutritional value of soy proteins [197,198]. 

O Quinn, P. R., J. L. Nelssen, R. D. Goodband, D. A. Knabe, J. C. Woodworth, M. D. Tokach, andT. T. Lohrmann. Nutritional Value of a Genetically Improved High-Lysine, High-Oil Corn for Young Pigs./. Anim. Sci. 78 (8), 2144-2149 (2000). [The availability of amino acids affects the proteins formed.]... 

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