Influence of Water and Glycerol Contents on the aw of Fish Pastes

Abstract

The influence of fish water content on the characteristics of water activity (aw) of reduced paste was studied. Two fish species were used: a fat species, mackerel (Scomber japonicus marplatensis), and a lean species, Brazilian sandperch (Pseudopercis semifasciata). Glycerol (from 15 to 50%) was used to decrease aw of the cooked fish paste. The possible influence of sex on the water and lipid contents of mackerel was also studied. According to the results of the statistical analyses there are not significant differences on water and lipid contents of male and female mackerel. Relationships of aw versus percent added glycerol were determined. Water content of raw materials was used as parameter as is common in products of reduced aw. Due to the extreme values of water content (54.12% and 77.89%) in mackerel, two relationships of aw versus percent added glycerol were obtained, and for Brazilian sandperch one relationship was obtained.