Chlorophyll in Citron (Citrus medica L.)

Abstract

The variation in the chlorophyll content of citrons was determined at different stages of maturity and at different depths in the mature green fruit. Fruit at different stages of maturity (immature green, mature green, turning ripe, and ripe) was selected from a commercial farm in Adjuntas, Puerto Rico. An examination of the endocarp revealed that it was of a greenish tint in the immature green fruit, greenish yellow in the mature green, completely yellow in the turning ripe, and whitish yellow or cream in the fully ripe fruit. Spectrophotometric determinations were made at different depths of the fruit, showing that the chlorophyll content was highest in the immature green fruit, with the mature green following closely. The chlorophyll content of fruit turning ripe was substantially lower than in the first two stages of maturity but higher than in the ripe fruit. The chlorophyll content of the citron diminishes considerably from one tissue layer to another as one cuts deeper into the fruit. Nevertheless, tissues of immature and mature green fruit contain a good amount of green pigment at greater depths. Because greenness is a characteristic index of quality in candied citron, it is advisable to use immature and mature green fruit for this purpose.