Milling procedures and air classification of amaranth flours

The different milling characteristics of Amaranthus cruentus, a domestic variety prevailing in Mexico, selected as representative sample, are herein discussed. This was subjected to proximate analysis, which confirmed its good quality. Milling trials were carried out for the preparation of whole flour by means of conventional mills and by combining some of these with the Raymond and Alpine separators for air classification. Results were then compared to those obtained with a Strong-Scott pearler. Grits and bran contained the highest protein concentration. After comparing overall results, it may be concluded that the best operating conditions are the following: a) seed pearling using five passes, in a pearler, with variable yields of approximately 22% containing 36% protein, and b) combining the Miag mill and Raymond air separator, with variable yields of approximately 32% and a protein content of 30-36%. Proximate analysis of the fractions as well as farinographic and amylographic characteristics--different from those of whole wheat and amaranth flours--suggest their use in the preparation of nutritionally-enriched food products.