EN 15652:2009

Foreword
1 Scope
2 Normative references
3 Principle
4 Reagents
5 Apparatus
6 Procedure
7 Calculation
8 Precision
9 Test report
Annex A (informative) - Typical chromatogram
Annex B (informative) - Precision data for acid-,
        enzymatic- and acid/alkaline hydrolysis
Annex C (informative) - Comparison between three
        different ways of hydrolysis
Bibliography

by high performance liquid chromatography (HPLC) by three different ways of hydrolysis, acid hydrolysis (A),enzymatic hydrolysis (B) or acid/alkaline hydrolysis (C).The method has been validated in interlaboratory tests on fortified and non-fortified samples such as breakfastcereal powder, chocolate cereals, cooked ham, green peas, lyophilized green peas with ham, lyophilized soup,nutritive orange juice, milk powder and wheat flour, at levels from 0,5 mg/100 g to 24 mg/100 g. For furtherinformation on the validation data, see Annex B.A and B give similar results for niacin. In options A and B niacin is calculated as the sum of nicotinamide andnicotinic acid, and expressed as nicotinic acid [1]. Option C gives higher results than A and B for niacin withnon-supplemented cereals, but similar results for other products. In option C, niacin is calculated andexpressed as nicotinic acid after transformation of nicotinamide into nicotinic acid [2].Option A is faster and cheaper than B and C.Option B is used if an exact quantification of nicotinamide and nicotinic acid is needed. This cannot be donewith option A, because there is a slight transformation of nicotinamide into nicotinic acid during the acidhydrolysis.Option C quantifies total niacin. The alkaline hydrolysis is able to liberate other forms giving higher results forniacin, which in some foods such as maize and cereals are not normally biologically available, see [3], [4] and[5].Information on a comparison between the three different ways of hydrolysis is given in Annex C.