It is well-known that the fruit of Citrus Natsudaidai tastes more bitter, being increased naringin content in its juice by heating and this fact is one of the greatest reason that manufacturing of Citrus Natsudaidai make not so rapid progress.
Many papers have been reported on removal of this bitterness but neither works accomplished sufficiently their purposes as yet. And this experiment was carried out to get a clue to perfect removal of this bitterness by finding out the mechanism of increasing of naringin content in juice.
(1) Naringin content in juice increased with the progress of ripening stage.
(2) By means of affecting pectinase on the fruit texture naringin was extracted more easily from the texture.
(3) Dipping the fruit texture in hot water, naringin in the texture was almost extracted into dipping water but in the case of existence of <Ca>^<＋＋> in dipping water, if it was hot, extraction of narigin from the texture was inhibited.
From mentioned above, close relation was recognized between naringin and pectic substances in the fruit texture and it is assumed that insoluble pectic substances masked a part of naringin and inhibit to dissolve it into juice. Considering from this aspect, the fact that naringin content in juice increase by treatments such as heating, freezing and crushing of the fruit texture is able to be explain reasonably.