Determination and distribution of ascorbic acid in three tropical fruits

An iodimetric titration was applied for determination of ascorbic acid (AA) in three tropical fruits: araca (Eugenia sp), acerola (Malphigia sp), and orange (Citrus sinenses). According to superficial color the fruits were classified as immature (green), medium maturity (green-yellowish), and mature (yellow or red). The fruits were frozen to minimize AA oxidation. The AA contents of araca showed a gradient of concentration between the upper part and the down part of the fruit. The concentration in the upper part (C1) was always lower than the concentration in the down part of the fruit (C2). Similar behavior was observed for acerolas and oranges, which presented a mean concentration in the upper part of 17.7 mg g(-1) and 0.612 mg L-1 and in the down part of 19.6 mg g(-1) and 0.665 mg L-1, respectively. It can be concluded that the three fruits presented a heterogeneous distribution of AA and the variation was more pronounced for immature fruits, i.e. fruits less suitable for ingesting.