Effect of cultivar, year grown, and cropping system on the content of tocopherols and tocotrienols in grains of hulled and hulless barley

In a three-year period (2000-2002) total tocols (tocopherols and tocotrienols), content of vitamin E and its isomers (alpha-, beta+gamma-, delta-tocopherols and tocotrienols) were assessed in grain of 13 barley genotypes. The highest content of tocols (60.3-67.6 mg kg(-1)) and content of vitamin E (Vitamin E equivalent-18.0-20.1 mg kg(-1)) were determined in the waxy varieties Wanubet, Wabet, and Washonubet. Standard varieties, i.e. of a malting type (Krona and Kompakt), had statistically significantly lower content of tocols (49.9 and 53.6 mg kg(-1)) and vitamin E (15.7-16.1 mg kg(-1)) compared to the waxy varieties. The hulless waxy variety Washonubet had statistically significantly higher total content of tocols (67.6 mg kg(-1)) and alpha- tocotrienols isomer (42.1 mg kg(-1)) versus all other genotypes in the set. Chemical treatment and fertilization statistically significantly increased the content of tocols (by 4.7 mg kg(-1)), vitamin E (by 1.9 mg kg(-1)), isomer alpha-tocopherol (by 0.9 mg kg(-1)) and isomer alpha- tocotrienols (by 3.3 mg kg(-1)). The average values of alpha-tocopherols and alpha-tocotrienols in the set were 6.7 mg kg(-1) and 29.7 mg kg(-1), respectively. Some of the reciprocal lines created by us from the malting and waxy varieties are suitable for food use for high contents of all tocopherols and alpha-tocotrienols.