Abstract
Quinolinic acid, trigonelline, N^1-methylnicotinamide and niacin contents in various common Japanese foods were determined. Quinolinic acid was distributed widely, and the highest content found in "katsuobushi" (dried bonito) was 5.3mg/100g. Very high correlation between quinolinic acid content and niacin content was observed (r=0.936). Trigonelline was localized in some sea foods, pea and coffee bean. Trigonelline content in coffee bean was extremely high, nearly one percent. Generally speaking, N^1-methylnicotinamide was distributed mainly in the foods of animal origin. The highest content was 3.2mg/100g in dried "wakame" seaweed (Undaria pinnatifida). Quinolinic acid, trigonelline and N^1-methylnicotinamide were proved to be converted into nicotinic acid or nicotinamide after being heated at over 180℃. It was suggested that these compounds in foods were converted into vitamin after high temperature cooking. In addition to quinolinic acid, trigonelline and N^1-methylnicotinamide, some unknown compounds which are converted into nicotinic acid or nicotinamide during high temperature cooking may be present in foods.
