Colorimetric Determination of Sulfite in "Kanpyo"(Dried Gourd Shavings) and "Konnyaku-seiko"(Devil's-tongue Fine Powder) Using Sulfite Oxidase and Catalase.

A simple and convenient method for colorimetric determination of sulfite in foods based on its conversion to formaldehyde with sulfite oxidase and catalase was developed. Sulfite in a sample was extracted with water and then diluted with methanol. One mL of sample solution containing about 5-10 micrograms of sulfite was taken into a test tube with a ground-glass stopper, and 3 mL of 0.04 mol/L bor…