Bread protein quality

Patent flour has two classes of use. It can be used to make whiter bread or where very high protein content is required. The use of patent flour to make bread seems to be dying out. Its use does, however, remain popular in South Wales. There are various examples of products where patent flour is used for its protein quality, e.g. filo pastry and West Indian patties. Both of these products are brown so the colour of the flour is not important. 

Cottonseed, peanut, sesame seed, and soybean flours, when used as supplements, add to the quality of the protein. The improvement of protein quality was due to the flours compensating for limiting amino acids. Supplementation using various flours improved total protein, amino acid content and some physical characteristics in akamu, yeast bread and sugar cookies. 

Wheat <Dairy products> starch, protein, moisture, ash, hardness, damaged starch, a-amylase activity, amino add, color value, ratio of contaminated bran, bread making quality, discrimination of cultivar... 

From PER and net protein ratio (NPR) tests, Palamidis and Markakis (12) later also found that the PER of bread mix (ingredients) or bread mix with 4% nonfat dry milk (NFDM) were 0.75 or 1.17, as compared to 0.46 or 0.75 for their corresponding breads, respectively. The findings also clearly show that baking can damage the nutritive quality of bread protein significantly and that fortification of NFDM can raise the PER of bread mix and wheat (white) bread. 

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. 

Payne P.I. Genetics of wheat storage proteins and the effect of allelic variation on bread-making quality. Artnu. Rev. Plant Physiol. 38 141-153, June 1987. 

Singh, N. K., R. Donovan, and F. MacRitchie. 1990. Use of sonication and size-exclusion high-performance liquid chromatography in the study of wheat flour proteins. II. Relative quantity of glutenin as a measure of bread-making quality. Cereal Chemistry 67 161-170. 

Bushuk, W., and E MacRitchie. 1989. Wheat proteins Aspects of structure that determine bread-making quality. In Protein quality and the effects of processing, ed. R. Dixon Phillips and J. W. Finley, 345-369. New York Marcel Dekker. 

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. 

One property of the flour that is controlled by the miller is the extraction rate. Wholemeal flour has a 100% extraction rate, with brown, white and patent white having progressively reduced extraction rates. One obvious difference is the colour. Another is that the quality of the protein increase towards the middle of the wheat berry from which patent flour is produced. Thus, patent flour is sometimes used not to produce whiter bread but in products like hlo pastry or West Indian patties where the strength that patent flour gives is important and the colour is irrelevant. 

While any type of flour can be made in a wholemeal form some products probably can not be made from wholemeal flour. The problems are that although all the wheat protein is present the quality of the protein is lower towards the outside of the wheat berry. This effect would render the making of products requiring very high extensibility, e.g. filo pastry, very difficult. The other problem is that the bran particles tend to burst gas bubbles, reducing the amount of lift. Despite the above, wholemeal bread flour is common and wholemeal self raising flour can be made. 

In theory, analytical testing ought to be able to answer all pertinent questions but, unfortunately, it can not. While measuring the protein content will discriminate between a low protein flour and a high protein flour, the protein content will not necessarily guarantee that a given flour will make a satisfactory loaf of bread. The problem is that it is much easier to measure the quantity of protein present rather than its quality. 

Field Pea Flours in Bread Products. Legume flours, particularly soy, have long been incorporated into wheat-based products, both for their functional effects and for protein fortification. In general, increasing the levels of legume flours results in decreased loaf volume, lower crumb grain quality, and adverse flavor characteristics in the baked bread (Table III). 

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