Effect of soaking with hydrogen peroxide and carbonate/bicarbonate buffer solutions on chemical composition and protein extractability of desalted cod

Abstract

Cod salted with various combinations of NaCl, KCl, MgCl2 and CaCl2 were soaked for the first 24 h with a 0.2 M carbonate buffer solution (pH 9.5) or for the first 5 h with 1% hydrogen peroxide (pH 7.16). Chloride, ions and ash content in muscle were measured during the soaking process. After soaking, the composition of soluble muscle protein extracted in NaCl 0.86 M was determined by SDS-PAGE. The divalent, cation content was not affected by the salting and soaking processes. The protein extractability was low, especially when H2O2 was used. The use of alkaline buffer solution produced better protein functional quality. When the alkaline solution was used for soaking, the soluble fraction was constituted of a larger variety of proteins. Actin was soluble only when MgCl2 and KCl were used for salting and the alkaline solution for soaking. The use of carbonate/bicarbonate buffer solution for soaking could therefore be useful to improve the functional quality of muscle protein of desalted cod.