Effects of Na+, K+ and Ca2+ on gels formed from fish mince containing a carrageenan or alginate

The effects of mixtures of added chloride salts (0-1% NaCl plus 0-1% KCl plus 0-1% CaCl2) on the characteristics of blue whiting muscle gel containing different added gelation agent (iota-carrageenan, kappa-carrageenan, or sodium alginate) were studied by response surface methodology (RSM) and factor analysis (principal component analysis). The salts exhibited independent effects on gel properties. NaCl mainly altered breaking strength in the gels made with iota-carrageenan, the yellowness (b(*)) value in the gels made with kappa-carrageenan, and adhesiveness in the gels made with sodium alginate. KCl mainly affected adhesiveness in the gels made with one of the carrageenans, especially iota-carrageenan; it had no apparent effect on the gels made with sodium alginate. The effect of CaCl2 in all the formulations was mainly to increase elasticity and lightness and decrease the rest of the properties considered. Combined action of the salts did reveal certain significant interactions, such as the interaction between sodium and calcium which affected the folding test value in the gels made with alginate and breaking strength in the gels made with iota-carrageenan, or the interaction between potassium and sodium which affected the redness (a(*)) value in the gels made with iota-carrageenan. Factor analysis showed the main trends in the variables tested, calcium being the salt that exerted the primary influence and contributed to the first two factors in each of the factor analyses. Each of the salts contributed to a separate factor, the only exception being the mixture of CaCl2 and KCl in the formulations that contained iota-carrageenan, in which both salts contributed to factor 1. (C) 2002 Elsevier Science Ltd. All rights reserved.