Nutritional value

FIGURE 1.12 Comparison of cereals with different types of food sources in terms of per capita food, caloric, and protein intake. (From FAO (Food Agriculture Organization). 2009. Statistical Database. Rome, Italy. Electronic page http //faostat.fao.org) 

The new trend in cereal breeding programs is to select genotypes with special uses and with better nutraceutical properties. These new genotypes are rich in carotenes (P-carotenes, lutein, zeaxanthin), phytosterols, phenolics, anthocyanins, tannins, and other antioxidants. These value-added grains will gradually gain market because of their proven health benefits. 

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Nutritional content Nutritional labeling Nutritional value... 

Dry Foods. Dry foods are concentrated sources of nutrition and provide the most economical nutritional value because water in canned foods is expensive. Dry foods tend to scrape the teeth as pets eat, minimizing tartar deposition. When dry food is moistened prior to being consumed, tartar accumulates in a manner comparable to deposits observed with caimed foods. Approximately 95 to 98% of dry-type cat and dog foods are made by the extmsion process the remainder is made by pelleting or baking. 

Four features of food are recognized to determine acceptance, ie, flavor, nutritive value, appearance, and mouthfeel. When all four aspects are in proper quantitative proportions, a food finds general acceptance. When all four are interdependent, appearance takes precedence over the others. However, a report by the Food Marketing Institute has shown that consumers placed nutrition second to flavor in importance (6). 

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. 

Protein Content. The protein content of milk can be determined using a variety of methods including gasometric, Kjeldahl, titration, colorimetric, and optical procedures (see Proteins). Because most of the techniques are too cumbersome for routine use in a dairy plant, payment for milk has seldom been made on the basis of its protein content. Dye-binding tests have been appHed to milk for determination of its protein content these are relatively simple to perform and can be carried out in dairy plant laboratories. More emphasis will be given to assessing the nutritional value of milk, and the dependence on fat content as a basis for payment will most likely change. 

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). 

U.S. Department of Agriculture, Nutritive Value of Foods, Home and Garden Bulletin No. 72, U.S. Government Printing Office, Washington, D.C., 1991, pp. 10-14. 

Amino acids are important components of the elementary nutrients of living organisms. For humans, ten amino acids are essential for existence and must be iagested ia food. The nutritional value of proteias is governed by the quantitative and qualitative balance of iadividual essential amino acids. ... 

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. 

The colorant is used at 2—50 ppm as pure color to shade margarine, shortening, butter, cheese (4 ), baked goods, confections, ice cream, eggnog, macaroni products, soups, juices, and beverages (58). Its chief advantages over other colorants are its nutritional value and its abiUty to dupHcate natural yellow to orange shades. 

Some countries, such as Germany, have laws that restrict imitation dairy products. Products that simulate milk and other dairy food of recognized nutritional value generally are required to be nutritionally equivalent to the dairy products that they imitate. In the United States, where legal standards exist for many substitute dairy products, the laws are less restrictive. 

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. 

Nahrungs-rohr, n., -rShre, /. alimentary canal, -sait, m. nutrient juice specif., (Med.) chyle, (Bot.) sap. -stoff, m. nutritive substance, nourishment, food. -stSrung, /. nutritional disturbance, -teilchen, n. nutritive element, -vergiftung, /. food poisoning, -wert, m. nutritive value, -zufuhr, /. food intake. 

Nahr-vorrat, m. reserve food, -wasser, n. nutrient solution, -wert, m. nutritive value, food value. 

The researcher in food and its analysis is keenly aware that his task will not be finished until the quality of a food product can be defined completely in precise terms of its flavor, color, texture, and nutritive value. The goal is distant but the journey is well begun. The papers contained herein describe the present state of affairs in each of as many of the fields of food analysis as time for the symposium permitted. Each has been covered by an outstanding worker in his field. It is unfortunate that B. L. Oser s excellent paper on Advances in Vitamin Determination does not appear. His more comprehensive review of food analysis which appeared in Analytical Chemistry [21, 216 (1949)] should by all means be studied along with the papers contained herein. 

Because overblanching may result in undesirable changes in color, flavor, taste, and texture and the loss of nutritive value, it is as important to avoid overblanching as underblanching. The availability of a method for the detection of overblanching is indicated, but so far as the writer is aware, none exists at the present time. In view of the fact that complete peroxidase inactivation is not required for quality protection, a measurement of residual peroxidase activity might provide the basis for such a test. 

One of the most prominent problems confronting the modem food processor is the prevention of rancidity. Rancidity affects not only the palatability of the food but the nutritive value as well—for example, oxidative spoilage of fats has been shown to be responsible for the partial destruction of the essential fatty acids (6) and of other dietary nutrients such as vitamins A (12) and E (9), and perhaps D (26) and certain members of the B complex (5, 29, SO). When one considers that nearly every food contains some fat and that this fat is subject to oxidative spoilage, the magnitude of the problem of rancidity is at once obvious. 

Ascorbic acid is added to many foods for its nutritive value. It is used extensively as an antioxidant to prevent flavors and colors from being damaged by oxidation. It is often used in canned or frozen fruits to prevent the browning that accompanies oxidation. While not as powerful an antioxidant as sodium bisulfite, it has a better nutritional reputation. 

Fats are food. But apart from their nutritive value they are also used as ingredients to modify other foods. Flaky piecrusts, smooth ice cream, and melt-in-your-mouth chocolates owe their properties to the unique characteristics of fats and oils. 

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