| 摘要 |
PURPOSE:To produce a soy having low salt content and excellent taste and flavor in high productivity, by treating a soy with a semi-permeable membrane having sulfonic acid group, thereby separating and removing salt selectively at a high rate of permeation under a relatively low pressure even in the case of a soy having high salt concentration. CONSTITUTION:A soy having low salt content can be produced by treating a soy with a semipermeable membrane having sulfonic acid group. The semipermeable membrane having sulfonic acid group is preferably a composite semipermeable membrane composed of (A) a skin layer having solute-separation activity and consisting of (i) a sulfonated polyaryl ether obtained by sulfonating a polyaryl ether composed of the unit of formula I (R is -CO- or -SO2-) or (ii) a sulfonated polyaryl ether obtained by sulfonating a linear polyaryl ether copolymer composed of the recurring unit of formula I and the recurring unit of formula II (R' is C-C bond or bivalent group) and (B) an ultrafiltration membrane integrated with the layer A and acting as the supporting membrane of the layer B. |
