Assessment of thiamine content in some dairy products and rice milk

The levels of thiamine were compared between different types of milk, fermented milk products and rice milk. The analysed products were mainly from the markets, so vitamin analysis may be a good parameter for the quality of commercial food. Thiamine concentrations were determined by high performance liquid chromatography (HPLC) using a reversed-phase C-18 column with fluorescence detector. The average thiamine contents were 0.46 mu g/mL for ultra high temperature (UHT), 0.39 mu g/mL for pasteurized and 0.38 mu g/mL for chocolate milk. Unprocessed cow milk had average thiamine concentration of 0.47 mu g/mL. The highest thiamine content (11.95 mu g/mL) was found in rice milk. Sour cream samples had higher concentration of thiamine (0.54 mu g/mL) than yogurt (0.45 mu g/mL) and sour milk (0.47 mu g/mL). In the opened UHT milk packages, which were stored in refrigerator for 10 days, significant thiamine loss was not observed. Investigated products contained appropriate amounts of thiamine and had satisfactory nutritional value with respect to vitamin B-1.