Study of a Method to Control the Amount of Sodium Chloride and Citric Acid in Pickled Fruit Products

Abstract

Pickles are typical of processed foods that use salt in their manufacture. We examined a method for assuring the quality of the end product by controlling the use of salt in the manufacturing process. In this study, we used the process for producing Japanese pickled plums as a model, and investigated how the amount of sodium chloride in the finished plum product could be controlled by the addition of salt and the type of salt that was used. We also examined how the amount of citric acid could be controlled by immersing the plums in a salt solution. Our results indicated that the amount of sodium chloride that transferred into the fruit changed according to the difference between the sodium chloride concentration in the fruit and that in the salt water. By adjusting the amount of salt and using different types of salt so as to vary the sodium chloride concentration of the liquid in which the plums were immersed, we showed that it is possible to control the amount of sodium chloride in the finished plum product. On the other hand, although the citric acid concentration also changed according to the difference between the citric acid concentration in the fruit and that in the liquid, relative to the sodium chloride, the rate of transfer was low. By making the difference between the concentration of the citric acid in the plums and that in the liquid sufficiently great, however, we found that we were able to control the citric acid concentration to a satisfactory degree.