Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Abstract

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.

Keywords:

• Lysine
• Prolamins
• Storage proteins
• Threonine

Acknowledgment

This work was financed by grants to R.A.A. from Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil (01/13904-8). C.V.H. and R.A.A. wish to thank Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil) for the scholarship and fellowship received, respectively. The authors also wish to thank R.R. Ferreira for the technical assistance and fruitful discussions, F.C.A. Tavares (ESALQ/USP) for allowing L.H. Gomes and M.V.M. Lourenço to scan the SDS gels and use the Kodak Digital Science 1D software. Many thanks are also due to Dr. M. L. C. Vieira and Dr. M. H. P. Fungaro for helping in the similarity analyses.