Barley high-lysine

The proteins of different cereal flours vary in their amino acid composition (Table 15.10). Lysine content is low in all cereals. Methionine is also low, particularly in wheat, rye, barley, oats and corn. Both amino acids are significantly lower in flour than in muscle, egg or milk proteins. By breeding, attempts are being made to improve the content of all essential amino acids. This approach has been successful in the case of high-lysine barley and several corn cultivars. 

Hiproly This high-lysine barley is derived from a mutant and possesses a better essential... 

A diet based exclusively on cereals only provides about 50% of the protein requirement for growing infants. The most limiting amino acid in all cereals is lysine (Chapter 17). The second limiting amino acid for maize is tryptophan, whereas it is threonine in the rest of cereals. The high-lysine cereal types of maize, sorghum, and barley possess better nutritional value due to improved protein quality or essential amino acid balance (Anonymous, 1988, Balaravi et al. 1976). 

Balaravi, S.P., Bansal, H.C., Eggum, B.O., andBhaskaran, S. 1976. Characterisation of induced high protein and high lysine mutants in barley. J. Sci. FoodAgric. 27 545-552. 

Merola, J., Fontanel, P., Pons, A., and Blanco, J.L. 1987. Breeding for high-lysine barley The effects of mutant high lysine ris0 1508 in five european commercial varieties. Barley Genetics Newsletter. 17 35-39. 

L-Lysine< Lys 2,6-diaminocaproic add, H2N-(CH2)<-CH(NH2)-C00H, a basic proteogenic, essential amino acid, Af, 146 2, m.p 224 °C (d), [0] - 25.9° (e = 2 in 5 M HQ),-r 13.5° ( c = 2, water). The proteins of cereals (wheat, barley, rice) and other vegetable foodstuffs are rather poor in Lys. Children and young growing animals have a particularly high requirement for Lys, since it is needed for bone formation. Like threonine, Lys does not take part in reversible transamination. 

RP-HPLC of storage proteins can also predict quality in other cereals. In barley, RP-HPLC of hordeins [112,224] and high-MW glutelins [225] can reveal malting quality. In maize, Paulis et al. [226] showed by RP-HPLC that there are more y-zeins in quality protein maize than in normal maize this relates to lysine content and nutritional quality. RP-HPLC can relate protein composition to kernel hardness, density, and vitreosity of both normal maize and quality protein maize genotypes [227-229]. Differences between alcohol-soluble proteins of hard and soft endosperm of normal and quality protein maize show that the zein distribution influences kernel texture and hardness [230-232]. 

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