Effect of different salts on dewatering and properties of yellowtail barracuda surimi

摘要

Washing is an important process for surimi production, in which undesirable components in fish mince are removed, while myofibrillar proteins are concentrated. However, dewatering is less effective for some fish species. The use of appropriate salt can be a means to increase dewatering and simultaneously improve the gelling property of surimi. The impact of 0.45% NaCl containing CaCl2 or MgCl2 at various levels (0, 4, 8, 12, 16, and 20mM) as the third washing media on dewatering of washed mince and gel-forming ability of surimi produced from yellowtail barracuda (Sphyraena flavicauda) was investigated. When CaCl2 or MgCl2 was incorporated into the washing media, the contents of Ca or Mg ions in washed mince increased (p < 0.05), whereas the pH of washed mince slightly decreased (p < 0.05). At the same concentration, a higher dewatering of mince was observed when CaCl2 was used, compared with MgCl2 (p < 0.05). Differential scanning calorimetry indicated that the stability of myosin decreased when higher concentrations of both salts were used (p < 0.05), while no difference in the stability of actin was obtained. Washing mince with 0.45% NaCl containing 20mM MgCl2 yielded increases in breaking force of the gel of resulting surimi for both one-step and two-step heating processes by 46% and 33%, respectively, compared with the control (without CaCl2 or MgCl2 incorporation in washing media). The whiteness of the gel slightly decreased when the mince was washed with MgCl2 (p < 0.05). Microstructure revealed that a gel possessing a fine network with improved water-holding capacity was formed when the third media containing 0.45% NaCl and 20mM MgCl2 was used. The use of 0.45% NaCl containing 20mM MgCl2 was recommended to increase dewatering efficacy and improve gel strength of surimi from yellowtail barracuda by rendering a fine and ordered gel network.