EFFECT OF FROZEN STORAGE ON PROTEIN DENATURATION AND FATTY ACIDS PROFILE OF THE RED OCTOPUS OCTOPUS MAYA

The fishing industry is based largely on the cold chain to ensure the commercial viability of their products. Octopus is known for its high content of important components of the human diet, such as high-quality protein, nutritional lipid-soluble vitamins and essential ω-3 polyunsaturated fatty acids (∑PUFAs)  that have positive roles in human health. The effect of frozen storage on protein denaturation and lipid oxidation has been the subject of study in fish for several years and continues to be studied. Nevertheless, it is noteworthy that there has been little research done on quality changes in octopus species in the worldwide; in particular for O. maya, the effect of frozen storage on the protein and fatty acid profile has not been previously reported. This study aimed to study the quality changes that occur in the frozen preserved O. maya (943-1250 g) over a period of five months. The study focused on chemical changes to the protein and fatty acid profile. The acceptability of the octopus catch by each fleet was done based on an acceptance-sampling plan. The sample size for the sensory quality inspection was selected using the Inspection Level III, AQL =6.5. Samples from the same batch with an initial temperature of 4^oC were placed in a waterproof-waxed corrugated box for freezing. Each box containing 36 octopuses was frozen in a horizontal plate freezer set at -80^oC until the thermal center of the block reached -18^oC. The results show that essential ω-3 fatty acids were more affected than protein. The increases in formaldehyde (HCHO) and salt soluble nitrogen (SSN) were considered to be indicators of protein denaturation; however, until the fifth month, these compounds were not detectable in the SDS-PAGE pattern. Trimethylamine nitrogen (TMA-N) and total volatile base-nitrogen (TVB-N) increased during frozen storage but both parameters were within the accepted quality standards (Table 1). The total content of PUFAs was the most affected fatty acid group, since ∑PUFAs decreased by 6.07% at the third month and 9.28% at the fifth month. The data provided here might be useful in the future to establish a quality index for frozen stored octopus.