[Composition and stability of fatty acids from deboned cachama and sardine meat during freezer storage]

Free fatty acids from total lipids and phospholipids in minced fish flesh from three sizes of Cachama (Colossoma macropomum) and Sardine (Sardinella anchovia) were evaluated. Cachama's most abundant unsaturated fatty acids from the total lipid fraction were: C18:1 (31-38%); C18:2, n-6 (13-15%); and C20:4, n-6 (3-5%), while in sardine were the follows: C18:1; C20:5 n-3 (12-24%) and C22: 6,n-3 (7-24%). C20:5, n-3 increased with the size and C22:6,n-3 decreased. The variance analysis indicated that percentage of polyunsaturated fatty acids of n-6 series in the total lipids of cachama and n-3 series in sardine were affected by the storage temperature from -10C to -20 degrees C (p < 0.01). Storage time had effect on the stability of sardine fatty acids (p-0.01) and cachama (p < 0.05). Sardine minced flesh presented the highest value of free fatty acids at-10 degrees C during the second month of storage (620 mg%) while cachama at the fourth month (230 mg%). TBA- value in sardine increased at -10 degrees C from 5.5 to 23 mg of malonaldehyde in fourth months while in cachama these value were almost the same (2-6 mg-kg) during the storage period at -10 degrees C and -20 degrees C.