Variability in chemical composition of spring barley genetic sources

Seed samples of 110 spring barley genotypes (year 2003, location Piestany) were evaluated from two aspects: malting quality and dietary fibre content which has many health-promoting effects. For malting quality assessment, total starch and protein level and beta-amylase (beta-AMS) activity was determined. It is necessary low protein and high starch level as well as high beta-AMS activity. Resistant starch and beta-glucan level were estimated as components of functional foods. Barley genotypes were divided into six year-periods: period of Hana landrace populations ( 1900-1929), period of Valticky (1930-1939), barley of period 1946-1964, period of Diamant (1965-1971), Diamant serie (1972-1985) and period of short-stemmed, high yielded cultivars ( 1986-2003). Content of beta-glucan and resistant starch and beta -amylase activity were estimated by kits (Megazyme, Ireland), total starch by the polarimetric method in accordance with STN 46 1011-37 and protein value was determined by Dumas method. In 1900-1929 years, average of total starch and protein level were 56.9% and 15%, respectively. In 1986-2003 years, starch was increased to 59% and protein was decreased to 13.1%. Average activity of beta -amylase in each period was more than 800 units/g. It shows evidence of standard or picked malting quality. There were obtained negative correlation between starch and protein level and positive correlation between starch level and beta -amylase activity. From the aspect of low protein, high total starch value and high beta -amylase activity, best genotypes were: Jubilant, Kompakt, Karat, Nitran, and Slovensky kvalitny. All of these genotypes have beta -amylase activity above 1000 units/g. All examinated barley genotypes were rich in beta -glucan level (above 4%). Highest levels (above 5%) of this dietary fibre were found in genotype: Merkur, Orbit, Zlatan, Karat, Atlas and Perun. There were little differences among A, B and C malting quality as well as among six year-period beta-glucan level. In comparison with other cereals, resistant starch in spring barley is lower than in wheat, rye and triticale and on the other hand higher than in oat. Its level ranged about 2.4% and there were small differences between individual barley genotypes.