Effect of kappa-carrageenan and NaCl on initial freezing point of egg and surimi

Initial freezing points T-i of egg samples (melange of egg yolk and white, egg yolk, egg white) and surimi mixed with different mass fractions of kapp a -carrageenan (w = 1-10%), NaCl (w = 1-10%), and mixtures of NaCl and kapp a -carrageenan in mass ratio of 4:1 (w = 1-10%) were determined by use of d ifferential thermal analysis (DTA). Samples of surimi were prepeared in lab oratory conditions from Sardina pilchardus. Water content in surimi was 81. 50%, in egg yolk 47.65%, in egg white 88.1%, and in melange it was 64.41% b efore mixing with the added substances. Relations between decrease of the initial freezing point T-i as function of mass fractions w of the added substances were determined by linear regress ion. Coefficients of determination in range of R-2 = 0.94-0.98 for samples of surimi, and R-2 = 0.92-0.98 for samples of egg were obtained. The larges t effect of cryoscopic depression on initial freezing point T-i were exhibi ted by the samples of surimi with added: a) NaCl in the temperature range f rom -0.19 to -11.11 degreesC, b) mixtures of NaCl and kappa -carrageenan (f rom -0.19 to -9.08 degreesC), and c) kappa -carrageenan (from -0.19 to -0.7 2 degreesC). For the samples with pure NaCl the largest decrease of T-i was obtained for: a) egg yolk (from -0.59 to -20.77 degreesC), b) melange (fro m -0.59 to -8.74 degreesC), and c) egg white (from -0.50 to -7.37 degreesC) . The results are compared and discussed with Chang-Tao model for predictio n of T-i for meat.