CHEMICAL AND NUTRITIONAL CHARACTERIZATION OF AMARANTHUS (AMARANTHUS-CRUENTUS)

Two samples of Amaranthus cruentus harvested in 1987 (sample A) and 19 90 (sample B) were studied. Whole and refined flours were obtained. Th e whole flours contained 14.6 and 12.6% protein and 6.6 and 7.3 ether extraction, respectively. Both samples contained signfiicant levels of Ca, P, Mg and K. Amaranth oil contained 19% palmitic acid, 3.4% stear ic acid, 3.4% stearic acid, 34% oleic acid and 33% linoleic acid. Doco saenoic acid (C22:1) was present at the level of 9%. The ratio of satu rated to unsaturated fatty acids was approximately 1:3. The level of c rude fiber was 3.7% in the whole flours and 2.4% in the refined ones. Biological protein quality of flours was measured in the rat by the ne t protein ratio (NPR) method. The NPR values of the four materials tes ted ranged from 3.04 to 3.20 (NS), as compared with 4.08 for casein. T hese values are equivalent to 75-78% of the standard protein. Blends o f raw wheat flour and whole amaranth flour fed to rats produced a good complementary effect between proteins, as shown by PER test. Wheat fl our gave a poor PER value of 0.54. However, this figure increased with every increment of amaranth flour reaching a value of 2.15 for the bl end 25:75. The PER for the amaranth diet (0:100) was 1.94 (casein 2.77 ). As expected, the extrusion process applied to the wheat/amaranth an d corn/amaranth mixtures improved-the biological quality of the protei n. The wheat flour diet (100:0) gave a PER value of 1.64. Mixture 90: 10 produced a low non significant increase in the protein quality. Hig her levels of substitution, 30 and 50%, significantly improved the pro tein quality reaching PER values of 2.04 and 2.24 respectively. Corn/a maranth blends produced signficant increases only at the levels of 70: 30 and 50:50. The results of this study show that amaranth seeds are a valuable resource, containing a higher level of protein of better qua lity than cereals like wheat and com and may play an important role in human diets.