Behavior of certain tropical fruits during the dewatering-impregnation soaking process in sucrose solutions.

摘要

Kinetics of the dewatering-impregnation soaking process (DISP) of three tropical fruits, pawpaws (Carica papaya), mangoes (Mangifera indica) and bananas (Musa acuminata), were compared. All the experiments were carried out in a thermostated water bath system, with an initial sucrose concentration at 50 g sucrose/100 g soaking solution and temperatures varying between 30 and 60℃. Fruit was cut into pieces of 9 mm in thickness and 31 mm in diameter. Fruit behaviour in DISP was characterized by waterloss, solute intake and loss of fruit solutes over 300 min. A fruit/solution ratio of 1/6.5 allowed fruit solute transfers (vitamin, mineral salts, acids) toward the soaking solution to be evaluated by direct measurements of vitamin concentration, conductivity and pH of the solution. The lower the initial sugar content of fruit, the higher the solute gain. For the three fruits and for the operating conditions tested, losses in vitamin C evaluated from concentrated solution were less than 5 mg/100 g initial product. Those losses were most important during mango treatment. Finally, it was shown that an increase of temperature favoured mass transfers.