Stability of fried fish crackers as influenced by packaging material and storage temperatures

Abstract

The objective of the study was to determine the stability of fried fish crackers during storage at different temperatures. The physicochemical properties and lipid stability were examined at 25, 40 and 60°C for three months. Fried fish crackers were packed into two types of packaging with four different layers; (i) polyethylene terephthalate-polyethylene-aluminium-linear low density polyethylene (PET-PE-ALU-LLDPE), and (ii) oriented polypropylene-polyethylene-metallized polyethylene terephthalate-linear low density polyethylene (OPP-PE-MPET-LLDPE). The linear expansion and oil absorption in control fried fish cracker was 75.67 ± 5.86% and 27.86 ± 0.79%, respectively. The initial moisture of cracker ranged from 4.41 to 5.40% and decreased to 2.76 to 3.75%. There were also reductions in water activity of crackers from 0.503 to 0.243. For color, the loss occurred gradually within the storage time from 64 to 47% (L*), from 27 to 19% (b*), and increased from 4 to 9% (a*) due to lipid degradation. For both packaging, the hardness of crackers decreased significantly at 25°C and 40°C, but increased at 60°C. Regardless of temperatures and types of packaging, crispiness increased significantly throughout the storage. This textural changes were possible cause by a decrease in moisture content. The lipid yield of the cracker was not stable within the storage time and the concentration of conjugated dienes and thiobarbituric acid reactive substances (TBARS) showed a gradual increase. These results showed that fried fish crackers in the storage study had undergone lipid oxidation where changes in physical and chemical properties were observed.