Cereal protein quality

The seed contains a relatively high amonnt of essential amino acids (55) (Table VII). In contrast to other plant seed protein profiles, baobab seed protein contains a high amonnt of lysine. Becanse lysine is limited in most cereal plants, it may be possible to nse baobab seed protein to improve cereal protein quality, especially in weaning food mixtmes (55). The high protein solubility at acidic and alkaline pH snggests that the baobab seed protein could be an adequate food ingredient (55). 

The great flexibility of CZE has enabled its successful application to a wide variety of analytes ranging from inorganic ions to macromolecules. A very incomplete listing of these includes analysis of ionic drugs and metabolites in pharmaceutical formulations and body fluids analysis of foods, food supplements, and nutriceuticals analysis of milk and cereal proteins quality control and stabil-... 

The protein efficiency ratio (PER) of field pea flours is considerably less than that of casein (1.46 vs. 2.50), and somewhat less than that of soy flour (1.81). However, composites of wheat flour and pea or rice and pea (50% of the protein from each source) had PER s of 2 or more (22). Thus, supplementation of cereals with pea flour results in improvement of protein quality. 

Dong, F.M., Rasco, B.A., and Gazzaz, S.S. 1987. A protein quality assessment of wheat and com distillers dried grains with solubles. Cereal Chem. 64 327-332. 

Hacklcr, L.R. 1977. Methods of measuring protein quality Areview of bioassay procedures. Cereal Chem. 54 984-995. 

Baskaran, V. M., Malleshi, N. G., Jayaprakashan, S. G., and Lokesh, B. R. (2001). Biological evaluation for protein quality of supplementary foods based on popped cereals and legumes suitable for feeding rural mothers and children in India. Plant Foods Hum. Nutr. 56, 37-49. 

T.P. Labuza, K. Bohnsack, and M.N. Kim, Kinetics of protein quality change in egg noodles stored under constant and fluctuating temperatures. Cereal Chem., 1982, 59, 142-147. 

Egg protein is one of the best quality proteins and is considered to have a biological value of 100. It is widely used as a standard, and protein efficiency ratio (PER) values sometimes use egg white as a standard. Cereal proteins are generally deficient in lysine and threonine, as indicated in Table... 

Furosine, a marker of the Maillard reaction product, is a valuable indicator of food protein quality. It is a marker for thermal treatment in foodstuffs and is directly related to the loss of lysine availability. IPC was employed to determine furosine content in beverages based on soy milk and cow milk supplemented with soy isoflavones [39]. Furosine was also analyzed in 60 commercial breakfast cereals to assess their protein nutritional values. The higher the protein content in the formulation, the higher the furosine levels [40]. A simple IPC technique that uses 1-octanesulfonic acid as the IPR allowed the selective determination of histamine levels in fermented food [41]. 

Maleki, M., Hoseney, R.C., and Mattem, P.J. 1980. Effects of loaf volume, moisture content and protein quality on the softness and staling rate of bread. Cereal Chem. 57, 138-140. 

Jood, S., Kapoor, A.C., and Singh, R. 1995. Amino acid composition and chemical evaluation of protein quality of cereals as affected by insect infestation. Plant Foods Human Nutr. 48, 159-167. 

Table 2.5 compares the protein quality in terms of lysine, leucine, protein digestibility, and PDCAAS of different types of sorghum, including an early transgenic biofortified sorghum line and other major cereals ... 

The biological value of food proteins is greatly influenced by the ratio of their essential amino acids. Most food proteins, first of all plant proteins, are deficient in some essential amino acids. The limiting essential amino acid in legume and milk proteins is methionine, and in cereal proteins it is lysine. Beside the knowledge of the requirements of quality and composition of amino acids, it is equally important to know whether these amino acids can be best utilized as free amino acids, in the form of peptides or proteins. The following possibilities exist for improving the balance of essential amino acids in the proteins ... 

Madl, R.L. Evolution of protein quality determination. Cereal Foods World 1993,38, 576-577. 

Cereals are an important protein source and are processed into bread, pasta and noodles, breakfast cereals, and fermented drink. For all these applications the quality is determined, to a greater or lesser extent, by the gluten proteins which account for about half of the total grain nitrogen. There are also opportunities to develop novel uses for cereal proteins in both the food and nonfood indns-tries. It is important to study the wheat gluten proteins, particularly the deamidated SWP (soluble wheat protein) in relation to their structure and function. 

Cereal proteins are important not only for their nutritional quality but also for their functional role in foods. The analysis of cereal proteins by CE has been covered in several reviews. " " Cereal proteins are complex mixture of proteins that are often difficult to solubilize and separate. Because of this, a wide range of analytical techniques including CZE or sodium SDS-CE have... 

Less research has been carried out on millets than on other cereals. Nutritional quality is one area of priority. Like other cereals, millet has low contents of essential amino acids. For example, pearl millet contains in the order of 3 g lysine/100 g protein, whereas the World Health Organization recommends a minimum of 5.5 g/100 g. On the plus side, millets do not contain gluten proteins, so they are safe for those with celiac disease. Millets are low in certain minerals, including calcium. 

The crude protein content, which ranges from 70 g/kg DM to 150 g/kg DM, is increased by the apphcation of nitrogenous fertUisers. Oat proteins are of poor quality and are deficient in the essential amino acids methionine, histidine and tryptophan, the amormt of each of these acids in oat protein being generally below 20 g/kg. The lysine content is also low but is shghtly higher than that of the other cereal proteins. Glutamic add is the most abundant amino add of oat protein, which may contain up to 200 g/kg. 

About 950 g/kg of the nitrogen in oilseed meals is present as true protein, which has an apparent digestibility of 0.75-0.90 and is of good quality. AVhen biological value is used as the criterion for judging protein quality, that of the oilseed proteins is considerably higher than that of the cereals (Table 23.3). 

Similarly, cereal protein compositions are frequently related to grain or product functionality. Thus, it should be possible to correlate quality with the presence or amount of specific components. Finding such relationships in complex data sets is, however, not simple. Mosleth and Uhlen [85] first used the statistical procedure partial least squares (PLS) regression to identify quality-... 

HPLC methods have, during the last 20 years, become widely used and are now methods of choice for many cereal protein analyses. RP-HPLC is especially useful because of its speed, sensitivity, high resolution, reproducibility, and quantifiability and because it complements other methods. SE-HPLC is also widely used to determine MW distributions quickly and accurately and relate them to processing or quality. lE-HPLC has developed more slowly but is becoming useful. This chapter has reviewed these methods, with special emphasis... 

Ford, J.E. and Hewitt, D, (1979). Protein quality in cereals and pulses. 3. Bioassays with rats and chickens on sorghum, barley and field beans. Influence of polyethylene glycol on digestibility of the protein in high tannin grain. J. 

We have referred above to the nutritional quality of cereal protein. Much energy has been expended in attempting to modify the amino acid composition using various breeding techniques. Protein of Z. mays, for example, is noto-... 

Mixtures of beans and cereals have a protein quality which comes close to that of meat, milk, and other animal proteins. The highest protein quality is usually achieved in mixtures comprised of 50% bean protein and 50% cereal protein because the amino acid patterns of the two types of foods complement each other. Some examples of food combinations utilizing this principle are corn tortillas and refried beans, baked beans and brown bread, and rice and beans. 

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

Protein Quality of Grains. The people of southeastern Asia whose diets consist mainly of rice are usually short of stature, but the children of those who Immigrated to the United States are often taller than their parents. It appears that the higher quantity and quality of protein in the American diet is largely responsible for the taller children, because cereal grains alone do not provide sufficient amounts of lysine and other amino acids needed for optimal growth. Fig. C-39 shows the lysine and protein content of the major grains in comparison with cow s milk. 

The nutritional quality of diets based on cereals may be improved by adding higher quality protein in the form of (1) animal products or (2) legumes, both of which contain proportionately more lysine than grains. Other means of overcoming the problems of protein quality in cereal products are described in the sections that follow. 

New and Improved Varieties of Grains. Some of the limitations in the protein quality of the most important cereal grains have been overcome by cross-breeding them with mutant varieties so as to obtain new hybrids which have higher contents of both lysine and protein. Fig. C-40 shows how the new high-lysine and high-protein varieties compare with some of the older, more common varieties of the major grains. 

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