Nonwheat cereals

Most publications dealing with HPLC of cereals report on wheat. However, the results obtained for wheat are not necessarily valid for other cereals. As with wheat, research on nonwheat cereals usually deals with identification of varieties or cultivars and the evaluation of processing quality of the different varieties. 

This book is not intended to provide full coverage of all the cereals or to review all the literature in the area of cereal chemistry. This would be an impossible task and would prove detrimental to the coherence of the text. If significant contributions are not mentioned, this does not mean that their importance is not appreciated. The book is meant only to be a link with the knowledge that already exists in books and journals that has been advanced by the efforts of many. Much of the discussion is centered on wheat because most basic research has been carried out on this cereal and some of the most enlightened concepts have emerged from this work. However, these concepts are readily applicable to other cereals. When other cereals are relevant to the discussion, they are introduced. In order partly to rectify what may be perceived as an imbalance, a chapter devoted to nonwheat cereals is included. 

The relationships between cereal composition and functionality are discussed in Chapter 11. Together with knowledge of the genetic control of cereal components, these relationships lead naturally to the discussion in Chapter 12 of approaches to modifying functionality. Some selected aspects of nonwheat cereals are discussed in Chapter 13. Presently, much emphasis is given to health considerations of diets Chapter 14 covers some of the health-related topics in discussions of cereals. 

Also, the presence of compounds beneficial to health (phytochemicals) has been better elucidated, and these are found in greater concentrations in cereals such as barley and oats. As a result of these new findings, research is tending to shift toward greater efforts to study nonwheat cereals. This is reflected in an increasing proportion of publications on these cereals. Some of the areas where conceptual ideas are being applied or may be needed will be briefly mentioned in this chapter. 

One of the questions posed in Chapter 1 was "Why does dough from cereals other than wheat not have viscoelastic properties " It is well established that the gluten proteins of wheat are responsible for the viscoelastic properties of wheat flom dough (see Chapter 6). The requirements for a protein (or any polymer) to exhibit viscoelasticity are discussed in Chapter 14. One of these is that the protein should be above its glass transition temperature (Tg). Zein, the prolamin protein of maize, is found to contribute viscoelastic properties to a zein-starch dough when the temperature is raised above its Tg at that water content (Bushuk and MacRitchie 1989 Lawton 1992). This shows that it is possible to obtain viscoelastic properties with nonwheat cereal proteins. 

Production of aerated products from nonwheat cereals has been a goal for a long time. Utilization of nonwheat cereals such as sorghum would be enhanced if they could produce breads with consumer acceptance close to that of wheat breads. This would also create a niche market for the fraction of the population that is gluten intolerant (see Chapter 14). Success has been limited. 

Although rye is used for bread-making, its dough viscoelastic properties are much inferior to those of wheat. Nevertheless, because its proteins do show properties more similar to wheat than do other nonwheat cereals, a detailed study of them seems to be justified to determine how they differ from wheat proteins. This could lead to better understanding of the requirements for dough viscoelasticity of nonwheat cereals. 

Gluten intolerance and the question cf viscoelastic properties for nonwheat cereals... 

These products must contain at least 20% protein with a quality at least 95% that of case in (a major protein in cow s milk). The supplemental protein may be supplied by flours or meals made from nonwheat, cereals or oilseeds such as soybeans, peanuts, sunflower seeds, and cottonseeds. 

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