RHEOLOGICAL AND MICROSTRUCTURAL CHANGES IN GELS MADE FROM HIGH AND LOW-QUALITY SARDINE MINCE WITH ADDED EGG-WHITE DURING FROZEN STORAGE

This paper examines the influence of freezing temperature (-40 degrees C or -18 degrees C) and frozen storage temperature (-18 degrees C or -12 degrees C) on gels made from two different sardine minces (M1, hig h functional quality; M2, low functional quality), with the addition o f egg white as a gel enhancing ingredient. To characterize the washed mince, proximate analyses and protein functionality were determined. F reezing at either -40 degrees C or -18 degrees C caused no drastic cha nges in gel structure. Throughout the course of frozen storage of all samples, a decrease in the water holding capacity (WHC) was detected, along with an increase in the amount of protein soluble in 8 M urea. A t 90 days the gels frozen at -40 degrees C exhibited numerous ice micr o-crystals; however, they did not affect the external appearance of th e gel and had hardly any effect on gel strength, shear strength, hardn ess, cohesiveness or elasticity. On the other hand, at 90 days the gel s frozen at -18 degrees C and stored at either temperature exhibited l arge, macroscopically visible ice crystals. In these samples, gel stre ngth and shear strength increased while hardness decreased. No definit e changes attributable to mince quality were detected during frozen st orage.