Effect of Cultivar, Year Grown, and Cropping System on the Content of Tocopherols and Tocotrienols in Grains of Hulled and Hulless Barley

Abstract

In a three-year period (2000–2002) total tocols (tocopherols and tocotrienols), content of vitamin E and its isomers (α-, β+γ-, δ-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 α- 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 α-tocopherol (by 0.9 mg kg⁻¹) and isomer α- tocotrienols (by 3.3 mg kg⁻¹). The average values of α-tocopherols and α-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 α-tocotrienols.