Occurrence of Bound Salt in Freeze-concentrated Soy Sauce

Abstract

  Part of the salt in soy sauce formed no eutectic H₂O•2NaCl crystals at sub-zero temperatures and remained in a freeze-concentrated product. NMR line width of ²³Na was broader in the concentrated soy sauce than in the material. A broad line width of ²³Na was also observed in an aqueous solution of NaCl and a non-diffusible soy sauce fraction. The data indicate that part of the salt in soy sauce interacted with its non-diffusible fraction and that such bound salt formed no eutectic crystals.