Miller Magazine Issue: 136 April 2021

73 MILLER / aprıl 2021 COVER STORY The result was more than satisfactory. The vitamin D3 was found to have lost none of its activity even after a year of storage. The amount of cholecalciferol added re- mained constant throughout the test period. The ELCOvit raw material therefore proved its suitability and can be used in flour fortification programmes. The weak point is analysis Positive as this result is: when implementing the study, the Mühlenchemie team encountered unexpected diffi- culties. In the course of the research project, it emerged that it is a major challenge to measure vitamin D reliably in flour. The biggest problem is the very small amount of the micronutrient added. In quantitative determina- tion, even well-known, accredited laboratories came up against their limits. The results of the analyses requested by Mühlenchemie showed wide fluctuations and did not permit reliable conclusions as to the extent of degrada- tion of the vitamin D. Only one institute specializing primarily in flour analy- sis was able to determine the amount of cholecalciferol so precisely that it was possible to make a reliable as- sessment of the storage life of ELCOvit D 3 100. But only a very few laboratories worldwide have such a high level of expertise. Simplified procedure with indirect determination In order to make measurement of the vitamin D 3 pres- ent in flour possible nevertheless, Mühlenchemie recom- mends an alternative procedure in which the sensitive substance is determined in the premix instead of the flour. Since vitamin D 3 is present in an exponential form in the concentrated premix, quantitative determination is easier in this starting material. Moreover, the micro- nutrient premix contains no wheat flour, and this further enhances the validity of the analysis. After it has been checked, in an initial step, that the vitamin content of the premix conforms to the specifica- tion, a sample of the fortified flour is analyzed. Here, too, a pragmatic modification is made: instead of the chole- calciferol, another constituent of the premix such as iron or zinc is used as the reference substance. These min- erals are contained in much larger quantities and can be determined much more easily by laboratories than vitamin D 3 . Micronutrient premixes for flour fortification must have a high level of homogeneity in order to ensure uniform and adequate fortification. The iron or zinc values de- termined therefore permit reliable conclusions as to the amount of cholecalciferol present: if the content of the chosen mineral is within the prescribed range, the re- quired amount of vitamin D 3 will be present too. A further test series to simulate use in tropical countries The present study demonstrates that ELCOvit D 3 100 has excellent stability when stored un- der temperate climatic conditions. But since the results may differ when the product is used in hot, humid zones, Mühlenchemie will conduct further stability tests simulating the conditions prevailing in the tropics during the rainy sea- son. In this way it will be possible to assess the reaction of vitamin D under more extreme environmental conditions. It is also hoped that the practical research series will help to create greater awareness of the proper way to handle premixes among their users.