INFLUENCE OF DRYING METHODS ON PROTEIN CONTENT AND AMINO ACID COMPOSITION OF THREE FORAGE LEGUMES

Abstract

Forage samples of alfalfa (Medicago sativa L. ’Beaver’), sainfoin (Onobrychis viciaefolia Scop. ’Melrose’), and cicer milkvetch (Astragalus cicer L. ’Oxley’) were dried either in a forced-draft forage dryer, drying oven, or a microwave oven. The dry matter content, protein content, and amino acid composition were determined but the air-drying methods resulted in significant losses of dry matter compared with microwave drying, suggesting that the latter method is preferable for dry-matter determinations. Interactions between species and drying method were significant for some of the amino acid contents, but not for the limiting amino acids — methionine, isoleucine, and valine. Since protein scores, reflecting protein quality, and protein content of the three legumes were not affected by drying methods, any one of the drying methods would be satisfactory. However, large numbers of forage samples can be handled most conveniently in a forced-draft dryer.