Seasonal Changes in Organic Acid Levels in Satsuma Mandarin Fruit

Abstract

The first rapid increase of organic acid concentration in very young satsuma mandarin fruit (C. unshiu Marc.) may be related to transformation of sugars into malic acid via the addition of CO₂ to pyruvate. The decrease in organic acid concentration after the maximum is caused by both the dilution from fruit enlargement and an actual reduction in the absolute amount of citric acid. Differences in the characteristics of maturity among strains of satsuma mandarin are associated more with changes in the absolute amounts of citric acid in the pulp than with its concentrations. The late-maturing Fukuhara attained a maximum in its absolute amount of citric acid later in the season than the early-maturing satsuma strains.