Seed protein characterisation of eleven species of amaranthus

Abstract

The protein profile and the amino acid composition of eleven amaranth species have been studied. The following species were taken into account: A. viridis, A. powellii, A.muricatus, A. deflexus, A. graecizans, A. blitoides, A. retroflexus, A. blitum, A. albus, A. cruentus and A. hypochondriacus. Seed samples were obtained from wild populations located in the southwest of Spain. The protein profile was studied by gel filtration chromatography and denaturing electrophoresis. Profiles were similar in all taxa, with small variations in the molecular weights and amounts of the main seed proteins. Thus, after gel filtration chromatography six main fractions of around 300 kDa, 180 kDa, 120 kDa, between 40 and 50 kDa, 20 and 30 kDa and below 10 kDa were observed. On the other hand, the electrophoretic analysis showed peptides grouped into three main fractions, between 50 and 64 kDa, 33 and 37 kDa and 18 and 25 kda. The most balanced amino acid compositions were observed in the wild taxa A. muricatus, A. blitum and A. powellii showed the most equilibrated amino acid composition. A. hypochondriacus and A. graecizans showed the most deficient amino acid composition with limitations in five essential amino acids. These results show the potential of wild amaranthus taxa for their introduction as crops or their use in the improvement by hybridization mechanisms of other crops such as A. hypochondriacus.

Keywords

• amaranth
• amino acid composition
• protein profile
• seeds