Low-ammonium-salt fermented condiment and preparation method thereof

The invention relates to a low-ammonium-salt fermented condiment and a preparation method thereof, and belongs to the technical field of food processing. The preparation method comprises the following steps: performing microfiltration treatment on a fermented seasoning stock solution to obtain a microfiltration permeate; and carrying out nanofiltration treatment on the microfiltration permeate liquid to obtain the low-ammonium-salt fermented condiment. According to the preparation method, the characteristics of ion selectivity and relatively low rejection rate of monovalent salt of a nanofiltration membrane are utilized, and under the matching of proper pressure and temperature conditions, most of ammonium salts in the fermented seasoning are removed, so that the low-ammonium-salt fermented seasoning is obtained, and the content of the ammonium salts is less than or equal to 20%. The preparation method is mild in operation condition, ammonium salt and other bioactive substances can be effectively separated, t