Hordein Polypeptide Pattern in Relation to Malting Quality and the Varietal Identification of Malted Barley Grain

Abstract

A procedure is described for the extraction of hordein fractions from single seeds of barley and determination of their polypeptide composition by SDS-PAGE. Varietal differences in the hordein polypeptide pattern occur, and on the basis of this character the 28 varieties which are most widely grown in the U.K. can be divided into 11 groups. Whereas several of these groups contain varieties with similar malting quality, other groups contain both good and poor quality varieties. Examination of pilot scale malts and germinating seeds showed little change in the hordein polypeptide pattern during malting or the early stages of germination. Thus the procedure is suitable for use in the identification of malted grain as well as dry seed.

Hordein and Malting Quality in Northern Barleys

“…BAXTER and WAINWRIGHT (1979) suggested that, based on investigations of 16 cultivars, good malting quality was associated with the absence of SHEWRY et al (1980a), although some cultivars had similar hordein patterns, the malting quality characteristics were not always similar. The results from the experiment described in this paper, and those of a previous publication (SHEWRY et al 1980a), indicate that the quality scores can at best only represent an approximate assessment of the various characteristics of a complex property such as malting quality.…”

“…Considerable effort has been directed towards explaining why barley cultivars (Hordeurn vulgare L.) differ in their malting quality and the nature of the role of hordein in the process (BAXTER and WAIN-WRIGHT 1979;SHEWRY et al 1980a;SMITH and SIMPSON 1983;SMITH and LISTER 1983;MAR-CHYLO et al 1986). Barley used for malting must be low in protein as it is released from the protein bodies during germination and envelops the starch granules, rendering them less accessible to amylase ( PAYNE 1983).…”

“…Many authors (e.g., SHEWRY et al 1978aSHEWRY et al , 1980aSMITH and SIMPSON 1983;ROININEN et al 1992) have used hordein banding patterns to identify barley varieties. Little is known, however, of the extent of genetic variation in hordein quality, although it could significantly affect malting quality.…”

Hordein polypeptide patterns in relation to malting quality in Brazilian barley varieties

“…Characteristics of importance for malting quality, which can differ considerably among barley cultivars, include grain size, grain protein concentration, amount of extract obtained from the malt, diastatic power and seed nitrogen (Morgan et al, 1981;Henry, 1990;Weston et al, 1993;Eagles et al, 1995). phoresis is particularly attractive as a screening test to differentiate cultivars (Shewry et al, 1980a;Marchylo, 1987) and to determine malting quality (Baxter & Wainwright, 1979;Shewry et al, 1980a). Hordein has also been investigated through different approaches including RFLP analysis (Shewry et al, 1985;Molnar & McKay, 1991), DNA sequencing (Brandt et al, 1985;Entwistle, 1988;Chernyshev et al, 1989;Vicente-Carbajosa et al, 1992;Kanazin et al, 1993), analysis of the regulatory control of hordein genes , and determination of the mRNA encoded by each locus (Kreis et al, 1983).…”

“…Baxter & Wainwright (1979), after studying the B fraction of hordein proteins from 16 varieties, suggested that potential malting quality is related to variations in this fraction. Shewry et al (1980a) studied 28 barley varieties from United States which could be divided into 11 groups on the basis of hordein band patterns but the authors did not find a clear-cut relationship between B-polypeptides and malting quality. Riggs et al (1983), in a study of 84 varieties, identified 13 groups based on the band patterns of the B-hordeins, but were unable to demonstrate that varieties known to have good potential malting quality exhibited specific or even related band patterns, although two groups contained only poor malting types.…”