Processing of oilseeds to meal and protein flakes

The prime consideration during processing of oilseeds to meals and flakes, i.e. toasting or cooking, is the time‐temperature‐moisture content relationship. Protein dispersibility decrease of any of these variables, but there is a threshold value for each variable below which the denaturation rate is very slow. In general, denaturation of protein is measured by its water dispersibility, i.e., denaturation increases as protein water solubility decreases. Choice of the extraction process for oilseeds depends primarily on the oil content of the seed and the allowable protein denaturation during preparation for extraction. Seeds with oil contents up to 30% may be extracted directly in percolation extractors, with minimum protein denaturation. Higher oil content seeds must be prepressed with some denaturation or they can be extracted by an immersion process such as centrifuge battery to minimize protein denaturation. The desolventizing operation is the most critical in fixing the degree of protein denaturation, since all three pertinent variables are near or above their threshold values. The selection of the proper processing units to desolventize completely the meal but maintain desired limits will be discussed. Subsequent heat treatment after the desolventizing process may be used to denature the protein or may be minimized to prevent much further denaturation. Prompt cooling is necessary before storage to preserve the required protein denaturation values. Classification and sizing may be required to meet the meal specifications.