Separation, fractionation, and reconstitution

A direct approach to determining composition-functionality relationships begins by separating the different chemical components. Once the components have been isolated—say, from a cereal flour—it is possible to proceed in two main ways. The first is to add the component in different amounts to the flour and measure the response in terms of some parameter of functionality. This approach has been used for elucidating the effects of lipids and proteins of wheat flour. 

The second approach that can be used is to interchange corresponding components between different flours. An example is illustrated in Table 11.1. Flours from two wheat varieties, one of better quality (A) than the other (B), were each separated into three fractions gluten, starch, and solubles. The fractions of each flour were interchanged and bake-test loaf 

For the two flours, each separated into three fractions, the number of possible combinations is 2 = 8. The eight combinations are shown in Table 11.1. It should be noted that the first two combinations are simply the three components of each flour reassembled. It is vital that the functional properties found for the reconstituted flours be the same as those of the original flours. Only if this can be established can the results for the interchanges be considered to be reliable. An inspection of Table 11.1 shows that the gluten protein component is responsible for the differences in loaf volume. 

---