PROBLEM TO BE SOLVED: To provide a method for producing low-salt soy sauce by using an ion exchange membrane which has sufficient ion exchange performance and durability and is hardly deteriorated in ion exchange performance even if an electrodialyzer is operated for a long time.SOLUTION: There is provided a method for producing low-salt soy sauce by reducing the salt content in soy sauce by electrodialysis, wherein the electrodialysis is carried out by using an ion exchange membrane including a copolymer (P) comprising a vinyl alcohol-based polymer component (A), a vinylene-based polymer component (B) and a polymer component (C) having an ionic group as constituent components as a cation exchange membrane and/or an anion exchange membrane.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2016,JPO&INPIT【課題】十分なイオン交換性能及び耐久性を有すると共に、電気透析装置を長時間運転してもイオン交換性能が低下しにくいイオン交換膜を用いる減塩醤油の製造方法を提供する。【解決手段】電気透析により醤油中の塩分を減少させる減塩醤油の製造方法において、該電気透析を、ビニルアルコール系重合体成分(A)、ビニレン系重合体成分(B)及びイオン性基を有する重合体成分(C)を構成成分とする共重合体(P)を含有するイオン交換膜を、カチオン交換膜及び/又はアニオン交換膜として用いて行う、減塩醤油の製造方法。【選択図】図3
