Effects of modified starches on the freezing rate and gel characteristics of surimi from silver carp(Hypophthalmichthys molitrix)

For silver carp(Hypophthalmichthys molitrix)surimi with four kinds of modified starch or the conventional cryoprotectant(4% sucrose+4% sorbitol),the freezing rate,thermal properties parameters during freezing phase transition and gel characteristics at -20 and -80 ℃ were measured in order to compare the cryoprotective effects of additives during freezing.The results indicated that the freezing rate of surimi at -80 ℃ was significantly higher than that at -20 ℃.The additives could significantly reduce the freezing rate and the freezing phase transition enthalpy of surimi,and improve water-holding capacity of frozen surimi gel.Higher water-holding capacity was obtained in surimi with modified starch,compared with that of surimi with the conventional cryoprotectant(P<0.05).The freezing rate of surimi with 4% sucrose(Z)+4% cross-linking esterification starch(CES)was similar to that of surimi with 4% sucrose(Z)+4% acetic acid esterified starch(AAES),and both were lower than that of the other groups at -80 ℃(P<0.05).There was no visible difference in gel strength betweeen surimi with 4% Z+4% AAES and surimi with the conventional cryoprotectant.Meanwhile,their gel strength was higher than that of the other groups at -20 and -80 ℃,respectively(P<0.05).Therefore,4% Z+4% AAES appeared to be a promising alternative cryoprotectant of the conventional cryoprotectant in frozen surimi industry,due to its notable effectiveness on the prevention of surimi quality changes during freezing.