Nutritional value protein quality

Miscellaneous Grain Processes Nutritive Values Protein Quality of Grains Enriched or Fortified Cereals New and Improved Varieties of Grains Sprouted Grains... 

Improved seed characteristics improvement of nutritional value (protein or oil content), baking and melting qualities, or reduction in cooking time. 

The nutritional value or quality of individual proteins depends on whether or not they contain the essential amino acids in the amounts that are required. A number of different ways of determining protein quality have been developed ... 

World and U.S. Production Preparation and Serving of Legumes Nutritional Value Protein Quantity and Quality Legumes of the World... 

In addition to various studies on protein composition and distribution within the plant tissue [72], the influence of protein secondary structure on global crop attributes, such as nutritive values, baking quality, or digestive behavior, achieved increasing interest. 

Sullivan, J.S., Knabe, D.A., Bockholt, A.J., and Gregg, E.J. 1989. Nutritional value of quality protein maize and food com for starter and grower pigs. J. Anim. Sci. 67 1285. 

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. 

Tubers Tubers are quite commonly consumed by villagers in Burma. Other tropical countries also report sporadic use of winged bean tubers (59). However, in comparison to the available data on the nutrient, anti-nutrient composition and the protein quality of the seed flour, published data on the nutritional value of winged bean tuber is somewhat limited. The few reported studies dealing with a larger number of varieties grown in different locations (25,67-71) show that tubers are mainly composed of protein and carbohydrates. 

A report by Bressani et al. (3J7), which evaluated the nutritional value of diets based on starchy foods and beans, indicated that for the rat, sweet potato protein was of poor nutritional quality. When methionine was added to all diets to raise sulfur amino acids, sweet potato still required the largest amount of supplementation with bean flour to maintain animal weight (Table II). 

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... 

For example, the color of fresh fruit indicates ripeness and the time the fruit is most likely to taste best. Off-colors in cheese or meats are associated with poor flavor quality. Generally, we expect each food product to have a certain color. Deviations from this expected color can result in rejection of a product even when this color does not adversely influence the flavor or nutritional value of the food. If plant-protein products are to attain widespread utilization in food applications, the color they impart to the product must be considered an important factor in consumer acceptability. 

Fractionation of the protein has been shown to have an effect on nutritional quality ( ) Results summarized in Table V show that nutritive value varies according to the... 

Dietary protein provides essential amino acids. The quality of a protein is a measure of its ability to provide the essential amino acids required for tissue maintenance. Proteins from animal sources, in general, have a higher quality protein than that derived from plants. However, proteins from different plant sources may be combined in such a way that the result is equivalent in nutritional value to animal protein. 

Fluid milk contains approximately 3.5% protein (USDA, CFEI 1976). Casein, found only in milk, comprises about 82% of the total milk protein, and whey proteins, principally /3-lactoglobulin and a-lactalbumin, constitute the remaining 18% (Lampert 1975 Jonas et al. 1976). Casein, because of its excellent nutritional value, is used routinely as a reference protein to evaluate the quality of protein in other foods (Jonas et al. 1976 Hambraeus 1982). 

For practical purposes, the nutritional quality of UHT milk is similar to that of conventionally pasteurized milk (Miller 1985 Arnold and Roberts 1982 Burton 1980, 1982 Renner 1980 Kosaric et al. 1981 Katz et al. 1981 Ford and Thompson 1981). As with conventionally pasteurized milk, the degree of heat treatment and the conditions of storage can affect the nutrient content of the milk (Burton 1980,1982 Renner 1980 Kosaric et al. 1981 Ford and Thompson 1981 Mehta 1980). However, careful controls on UHT processing, along with proper packaging, can ensure that the nutritional value of milk with regard to protein, fat, carbohydrate, fat-soluble vitamins, most water-soluble vitamins, and minerals is retained (Ford and Thompson 1981). 

Determining protein quality analysis is important in food science, particularly for developing foods with targeted nutritional value, and in animal feeding and husbandry. Protein is the key component in the diet of any farmed species, particularly in aquaculture and the pet food industry, making an accurate assessment of protein utilization critically important. Protein quality analysis provides an estimate of the content and bioavailability of indispensable or dietary essential amino acids. 

A number of procedures used to determine protein quality involve bioassays. Bioassays require feeding live animals protein ingredients for a specified period of time, and then estimating the nutritive value of the protein. Two such assays are the rat-based protein efficiency ratio (PER) bioassay and the human nitrogen balance assay (Dimes et al., 1994). Animal feeding experiments require chemical analyses of both the dietary inputs and then the metabolic output of the animal (e.g., body composition analysis, fecal sample analysis, collection, and assay for urine) from which the efficiency of protein metabolism can be predicted as well as how the protein supports animal growth and cell maintenance. 

Values for a test protein will be lower than for the reference protein. The reliability of results for chemical scoring methods depends upon the accuracy of the amino acid determinations that form the basis for these assays. Chemical scoring and animal bioassays tend to provide similar relative rankings of protein quality however, the actual values may be different. Chemical scoring methods should not replace a bioassay for testing the quality of a food protein for which there is very little nutritional information. 

Nutritive value of foods and feedstuffs depends to a large degree on protein level and quality, i.e., the relative amounts of the component amino acids compared to the requirements of the animal for various metabolic functions. The cereal grains are notoriously low in certain essential amino acids. Usually lysine is the first or second limiting amino acid. The grain of rye (Secale cereale L.) exhibits an amino acid profile superior to that of other cereal grains, especially wheat (1,2,3,4,5). Despite this fact, lysine is still the first limiting amino acid in rye in most instances (6,7). 

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