A pitfall in determining the globulin/albumin ratio in amaranth grains.

In amaranth grains (Amaranthus hypochondriacus L. and Amaranthus cruentus L.), there were two albumin (Alb) fractions, Alb-1 and Alb-2; Alb-1 was extracted with water or 0.5 M NaCl, and Alb-2 was extracted with water after extracting Alb-1 and globulin. The amount of Alb-2 comprised about 30% of the total albumin and globulin content. Little or no measurable protein corresponding to the amaranth Alb-2 was extracted from seeds of buckwheat (Fagopyrum esculentum Moench), quinoa (Chenopodium quinoa L.), or barley (Hordeum vulgare L. cv Sekitorisai-1). That the globulin/albumin ratio (G/A) in amaranth grains has been conflicting among investigators probably accounts for the consideration of Alb-2 during extraction. We here report the revised G/A ratio of 0.3-0.4.