Protein concentrates nutritional value

Table 11. Nutritive Value of Leaf Protein Concentrates and Other Protein Products ...

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

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. 

The application of biosolids also increases the nutritional value of blue grama. Tissue levels of nitrogen, phosphorus, potassium, and crude protein increased to recommended tissue concentrations with biosolids treatments. Trace metals in blue grama grass did not increase during the study, thereby eliminating concerns that toxic amounts of these elements could be transferred to grazing animals. 

Marasmus is considered to be due to inadequate food intake. It is not usually the quantity but the quality of the food that is deficient, e.g. low nutritional value of bulky vegetables. Kwashiorkor is considered to be caused, more specifically, by a low-protein diet. This condition frequently develops at the time of weaning when protein-rich milk is replaced by protein-deficient solid food. It did not appear in the medical literature until 1934 when it was reported by Cicely Williams who studied the condition while she was working among tribes of Western Africa. She gave it the name kwashiorkor, which was used by the Ga tribe to describe the condition that develops when the baby is taken away from mother s breast, usually because another baby has been bom. It has generally been held that the oedema is a consequence of a low plasma albumin concentration and a reduction in the colloid osmotic pressure which reduces the movement of water from tissue fluid back into capillaries. The low albumin level results from a decreased rate of synthesis of albumin by the liver. However, if marasmus is due entirely to lack of energy... 

Zduhczyk et ol. (1996) studied the nutritive value of low-alkaloid varieties of white lupin and found that the lysine contents were relatively low (4.70-5.25g/16g N), with methionine as the limiting AA. Roth-Maier and Paulicks (2004) studied the digestibility and energy contents of the seeds of sweet blue lupins (L. angustifolius) and found digestibility coefficients of 0.43-0.5 for organic matter, 0.36-0.43 for protein, 0.69-0.83 for fat, 0.46-0.58 for NFE and an ME concentration of 7.54-8.22 MJ. 

Behavior of the Protein-Bound Isopeptides. The problem of protein-bound isopeptide absorption was investigated by Hurrell et al. (76) who found that these two isopeptides were not present in greater concentration than the other nitrogen compounds in the ileal and fecal contents of rats that were fed heat-treated protein containing aspartyl-and glutamyllysine. They proposed that the loss in the nutritive value of severely heated proteins was mainly due to a decrease in the nitrogen digestibility. The isopeptides appeared to be either absorbed by the intestine or metabolized by the intestinal microflora. 

In particular, we have concentrated on developing techniques for isolating protein to attain this objective we have studied the practical use of chemical modification. The application of chemical modification to food proteins has been explored for several purposes to block deteriorative interactions between reactive groups (e.g., e-NH2 and reducing sugars) to improve functional properties (solubility, flavor, and thermal stability) to enhance nutritive value and digestibility to facilitate the elucidation of interrelationship between structure and functional properties (6,7,8,9) and, as discussed herein, to facilitate the preparation of protein isolates. 

In clinical practice, only a few laboratory tests are of value in tlie assessment of protein-energy status It is particularly important to recognize that serum protein concentrations are not helpful in sick patients with any form of inflammatory process (see Chapter 20). Although serum albumin is often measured and reported as an indicator of protein-energy status, factors such as increased transcapillary escape and reduced hepatic synthesis malce it of little value as a nutritional marker. Serum albumin is, however, a valuable prognostic marker and is frequently used as part of prognostic indices. Short half-life proteins, such as transthyretin (prealbumin) also may be of some limited value in patients with no inflammatory response. 

Much research has been devoted to working out optimum parameters of producing different protein concentrates from fish and krill (Lanier, 1994). While the products have high nutritional value and many are tasteless and odorless, some, manufactured in denaturing conditions, lack the desired functional properties. A good example is the fish protein concentrate obtained by hot azeotropic isopropanol extraction. On the other hand, a concentrate of myofibrillar proteins known as surimi, produced mainly from fish and to a lesser extent from poultry and meat, is highly functional. 

Proteinaceous material such as horn, feather, nail, hair, and cheese whey occur in nature as waste and can be converted, by proteases, into liquid concentrates or dry solids with high protein content and of nutritional value for food and feed. Thus, proteases provide potential application for the management of residues from various food processing industries such as poultry and cattle slaughterhouses and fishing and dairy industries [5, 6],... 

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