Studies on changes in flour tocopherols following ageing and treatment of the flour with chlorine dioxide

The tocopherols in freshly milled flour were measured using two‐dimensional chromatography. Total tocopherols were in the range 1500–1600 μg/100 ml, but only 17–18% of this was α‐tocopherol. Aerobic storage for 190 days caused a reduction of all tocopherols by 62–67%. Treatment of the flour with chlorine dioxide at the usual commercial level caused a comparable reduction, averaging 58%; ϵ‐tocopherol was rather less affected than α‐tocopherol. Studies in human volunteers indicated that a daily supplement greater than 10 mg of tocopherol was needed to bring about a significant change in the level of α‐tocopherol in the blood. When bread made from untreated and chlorine dioxide‐treated flour was fed to groups of volunteers in a double‐blind crossover trial for 50 days on each type of bread, no significant correlation could be found between blood tocopherol levels and the type of bread consumed. To examine whether a longer period of time on the diet was necessary, the blood tocopherol levels of thirteen English students who had habitually consumed bread made from treated flour were compared with those of thirteen French students, matched for age, who had for several years consumed French bread which is made from untreated flour. The analyses were carried out in Birmingham and in Paris by the same investigator. No significant differences in tocopherol levels were found. It is concluded that the consumption of bread made from flour treated with chlorine dioxide will have no significant effect upon the blood level of α‐tocopherols under the dietary conditions at present prevailing in Britain.