A Compositional Study of Amaranth Grain

Abstract

The chemical composition of ten amaranth seed samples was determined. The saccharide content was determined using gas chromatography and high performance liquid chromatography. Sucrose was the major sugar followed by raffinose. Inositol, stachyose, and maltose were found in small amounts in most of the samples. Autolysis for 16 hr at pH 5.0 and 6.5 resulted in decreased sucrose and raffinose concentrations. Maltose was liberated by autolysis at pH 6.5 but not at pH 5.0. Inositol increased after autolysis. It was concluded that invertase, amylase, and phytase occur in the grain. Physicochemical properties of isolated amaranthus starch were measured and compared with analogous values reported for wheat starch. The lipids from representative amaranth grain varieties were analyzed for fatty acid composition. Squalene was present in the oil in large amounts, compared to other grains. The amino acid composition of the grain was used to calculate the chemical score (73) and the nitrogen to protein conversion factor (5.85). Leucine was found to be the limiting amino acid. Tannin and vitamin levels typical of other grains were detected. Mineral and proximate compositions were similar to previously reported values.