Effect of variety and environment on the amount of thiamine and riboflavin in cereals and grain legumes
Comprehensive information on B vitamin contents in cereals and grain legumes used for animal feeding is scarce. Thus, the objective of this study was to determine the contents of thiamine and riboflavin uniformly in a selection of cereals and grain legumes. Additionally, the evaluation of varietal and environmental effects on the amounts of both B vitamins was targeted. We analysed contents of thiamine and riboflavin with HPLC in 855 samples of different organically cultivated cereal and grain legume cultivars. Since the sample set was unbalanced, it had to be adapted for further statistical analyses. Data of 541 samples of ten cereal and grain legume cultivars was used to assess the influence of variety and environment with generalized linear models. Cereal grains contained 1.27–3.53 mg thiamine and 0.62–1.58 mg riboflavin/kg DM, which was less than expected from table values. Thiamine and riboflavin contents of grain legumes were mostly comparable with table values. Their thiamine contents ranged from 2.55 to 8.97 mg and their riboflavin contents from 1.00 to 3.84 mg/kg DM. Furthermore, variety, harvest site, and/or year affected B vitamin contents in all cultivars of our sample set. Due to wide variations of the contents of thiamine and riboflavin, we recommend to express values in food- and feed tables as ranges and to mention the number of underlying analysed samples. It must be considered that thiamine contents of cereal grains might be lower than expected from food- and feed tables.