Orthophenylphenol (OPP) content in lemon peels was reduced to less than half of its original content with the procedure used to remove bitter substances. OPP content in peels decreased little after dipping them in water. The increment of OPP content in marmalade was proportional to the ratio of peeled pieces of lemon. OPP content of lemon marmalade prepared by an ordinary procedure from lemons containing 2.3 ppm of OPP on whole basis was 0.39 ppm, about 17% of the initial amount of OPP being present in the final product.
1Present address: Department of Brewing and Fermentation, Tokyo University of Agriculture, Sakuraoka, Setagayaku, Tokyo, Japan.