Maize, wheat, amaranth, rice and soybean were screened for protein content. Alcoholsoluble (A1 and A2) and glutelin (G1 and G2) fractions were isolated and compared in terms of their amino acid and protein compositions. The average proportions of nitrogen content between total alcohol-soluble proteins (TASP) and total glutelins (TGlu) in the pseudocereals amaranth and soybean were about 1.8:26.9 and 14.9:12.3 respectively. In the cereals maize and wheat these proportions were 47.8:33.2 and 44.7:31.2 respectively. The sum of essential amino acids was 47.6 and 60.3 g per 100 g protein in amaranth and soybean respectively. The highest contents of methionine, lysine and arginine were found in the pseudocereals. The relatively high content of essential amino acids shows that pseudocereals could be used as a nutrient substitute for cereals.

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Intrinsic fluorescence (IF), surface hydrophobicity (S(o)), electrophoresis, amino acid analysis, circular dichroism (CD), and differential scanning calorimetry (DSC) were used to study folded and unfolded soluble proteins from Amaranthus hypochondriacus (A. h.) and soybean (S). Globulin (Glo) and albumin subfractions (Alb-1 and Alb-2) were extracted from A. h. and S and denatured with urea. Electrophoretic and functional properties indicated a significant correlation between soluble protein fractions from soybean and amaranth. The protein fractions shared some common electrophoretic bands as well as a similar amino acid composition. The larger percent of denaturation in protein fractions, which is associated with enthalpy and the number of ruptured hydrogen bonds, corresponds to disappearance of alpha-helix. The obtained results provided evidence of differences in their secondary and tertiary structures. The most stable was Glo followed by the Alb-2 fraction. Predicted functional changes in model protein systems such as pseudocereals and legumes in response to processing conditions may be encountered in pharmaceutical and food industries. These plants can be a substitute for some cereals.

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Polyphenols, phenolic acids, fibres and antioxidant capacity were determined in water, acetone and methanol extracts of buckwheat, rice, soybean, quinoa and 3 amaranth cultivars. Their antioxidant activities were comparatively assessed by total radical-trapping antioxidative potential (TRAP), ferric ion-reducing antioxidant power (FRAP), cupric-reducing antioxidant capacity (CUPRAC) and nitric oxide (NO • ) assays, which comprised of contributions from polyphenols and phenolic acids (especially from the most abundant ferulic acid). The correlation coefficients between polyphenols and antioxidant activities of cereal and pseudocereal methanol extracts with FRAP, NO • , CUPRAC and TRAP were 0.99, 0.97, 0.96 and 0.77, respectively. The weakest correlation was with dietary fibres, an average one exhibited with tannins and marked correlation was shown with the phenolics. All the applied methods have shown that pseudocereals have higher antioxidant activity than some cereals (rice and buckwheat) and can be successfully replaced by cereals in case of allergy.