AVERAGE MOLECULAR-WEIGHT AND GASTROINTEST INAL ABSORPTION OF A NATURAL FOOD COLOR GARDENIA BLUE

The natural coloring matter (blue color) produced from an aqueous extr act of gardenia fruits (Gardenia augusta MERR.) and the decomposed pro tein was found to be of a mean molecular weight of 15600 +/- 400, base d on the measurements of the osmotic pressure. The absorption from the gastrointestinal tract of this natural coloring matter was examined b y testing the stability of the color in the gastrointestinal tract, by observing the absorption, both in vitro and in situ, and by conductin g histopatholgical examinations of the gastrointestinal tract and othe r related organs in mice which had received the color for five months. The results showed that the color was very stable at the pH levels of the gastrointestinal tract and in the presence of digestive enzymes a nd enterococci. No evidence of the gastrointestinal absorption was obt ained.