Tocochromanol concentration, protein composition and baking quality of white flour of South African wheat cultivars.

摘要

Vitamin E has antioxidant properties and consists of four tocopherols and four tocotrienols ( alpha , beta , gamma and delta ), collectively called tocochromanols. This study was carried out to determine the tocopherol and tocotrienol concentration in white flour of 10 South African wheat cultivars grown in 3 environments, sourced from 2 breeding programmes alpha - and beta -tocopherols; alpha - and beta -tocotrienols were found in significant concentrations. The concentration of the tocochromanols in the white flour (4.87-11.73 mg kg-1) was much lower than that in whole flour of soft wheat (74.3 mg kg-1) and durum wheat (60.6 mg kg-1). The concentration of tocochromanols was strongly influenced by genotype, the environment and the interaction between the two. Cultivars originating from one breeding programme had a significantly higher concentration (9.12 mg kg-1) of tocochromanols than from the other breeding programme (5.28 mg kg-1). All of the cultivars had good baking quality characteristics (such as high loaf volume, protein content and wet gluten content). Loaf volume was significantly positively influenced by the sodium dodecyl sulphate (SDS) insoluble small polymeric and small and large monomeric proteins, as well as the SDS soluble large polymeric proteins. White flour could therefore be a complementary source of vitamin E in the diet, and selection for increased tocochromanol concentration can lead to increased nutritional value of bread wheat flour without a penalty to baking quality.