CONTENTS OF LIMONOIDS AND LIMONIN 17-BETA-D-GLUCOPYRANOSIDE IN FRUIT TISSUE OF VALENCIA ORANGE DURING FRUIT-GROWTH AND MATURATION

The amounts of limonoate A-ring lactone (LARL), nomilin, deacetylnomilin, and limonin 17-beta-D-glucopyranoside (LG) in the fruit tissue of Valencia oranges were measured during fruit growth and maturation. The LARL content (milligrams per fruit) in fruit tissue (flesh plus peel) increased sharply from June to September and then decreased gradually thereafter. The LARL concentration in the flesh dropped below 35 ppm when the fruit reached its normal maturity and its harvest season began. LG in the flesh began to appear in September of the fruit-set year, and its content increased until July of the following year. The amount of total limonin (LARL + LG) in fruit tissue continued to increase from July of the fruit-set year until around March of the following year and was fairly constant thereafter. The ratios of LG to total limonoid glucosides in fruit tissue ranged from 0.15 to 0.55. The accumulation patterns of nomilin and deacetylnomilin differed from those of limonin.