This study was conducted in the intention to identify and determine the fatty acid profile in freshwater fishes and marine fishes available at Malaysian wet market as well as its deterioration kept in ice storage up t...This study was conducted in the intention to identify and determine the fatty acid profile in freshwater fishes and marine fishes available at Malaysian wet market as well as its deterioration kept in ice storage up to 21 days. Three freshwater fishes： Oreochromis sp. commonly known as Tilapia, Monopterus alba commonly known as Belut, Pangasius hypothalamus commonly known as Patin and marine fish Rastrellinger kanagurta commonly known as Kembung, Thunnus tonggol commonly known as Tongkol and Epinephelus sp. commonly known as Kerapu with average weight of 500-600 g were tested with storage time of 1, 3, 6, 9, 12, 15. 18 and 21 days kept ice storage. The Fatty Acid Methyl Ester （FAMEs） were prepared using one step method and were identified by using gas chromatograph Agilent 6890N equipped with flame ionization detector. Separation was performed by injecting 1μL of a sample into the capillary column DB-225MS column （30 m length × 0.250 mm diameter × 0.25 μm film thickness）. The fatty acids peaks were indentified using Agilent Technologies software 5988-5871EN and comparing their retention time against the authentic standard Supelco 37 Component FAME Mix. Statistical results showed that palmitic acid （CI6：0） were the major fatty acids among the saturated fatty acids （SFA） while oleic acid （C 18：1 n9） were the major monounsaturated fatty acids （MUFA） detected in each sample studied. Both linoliec acid （C 18：2n6） and arachadonic acid （C20：4n6） were predominant in total omega-6 polyunsaturated fatty acids （PUFA）. The essential fatty acids show prominent in ecosapentanoic acid （C20：5n3） and docosahexanoic acid （C22：6n3）. During ice storage polyunsaturated fatty acids （PUFA） and monounsaturated fatty acids （MUFA） decrease as the time of storage increase. There is significant decrease in polyene index （PI） index of all the species throughout the storage time, The PI in freshwater fishes decrease by 70% in Tilapia, 90.1% in Belut and 90.9% in Patin, while for marine fishes, PI in Kembung decreases by 67.8%, 85.7% in Kerapu and 65.93% in Tongkol during kept in ice storage. During ice storage, the percentage of EPA, DHA and ALA decrease in Tilapia （55.36%, 13.86% and 75.41%）, Belut （78.55%, 87.74 % and 74.53%） and Patin （82.45%, 40.0% and 82.10%）, respectively. The same result were also observed in the marine fishes where the percentage ofEPA, DHA and ALA decrease in Kembung （94.27%, 49.03% and 88.52%）, in Kerapu （73.03%, 88.18% and 38.73%） and Tongkol （70.05%, 38.24% and 57.14%）, respectively.展开更多
文摘This study was conducted in the intention to identify and determine the fatty acid profile in freshwater fishes and marine fishes available at Malaysian wet market as well as its deterioration kept in ice storage up to 21 days. Three freshwater fishes： Oreochromis sp. commonly known as Tilapia, Monopterus alba commonly known as Belut, Pangasius hypothalamus commonly known as Patin and marine fish Rastrellinger kanagurta commonly known as Kembung, Thunnus tonggol commonly known as Tongkol and Epinephelus sp. commonly known as Kerapu with average weight of 500-600 g were tested with storage time of 1, 3, 6, 9, 12, 15. 18 and 21 days kept ice storage. The Fatty Acid Methyl Ester （FAMEs） were prepared using one step method and were identified by using gas chromatograph Agilent 6890N equipped with flame ionization detector. Separation was performed by injecting 1μL of a sample into the capillary column DB-225MS column （30 m length × 0.250 mm diameter × 0.25 μm film thickness）. The fatty acids peaks were indentified using Agilent Technologies software 5988-5871EN and comparing their retention time against the authentic standard Supelco 37 Component FAME Mix. Statistical results showed that palmitic acid （CI6：0） were the major fatty acids among the saturated fatty acids （SFA） while oleic acid （C 18：1 n9） were the major monounsaturated fatty acids （MUFA） detected in each sample studied. Both linoliec acid （C 18：2n6） and arachadonic acid （C20：4n6） were predominant in total omega-6 polyunsaturated fatty acids （PUFA）. The essential fatty acids show prominent in ecosapentanoic acid （C20：5n3） and docosahexanoic acid （C22：6n3）. During ice storage polyunsaturated fatty acids （PUFA） and monounsaturated fatty acids （MUFA） decrease as the time of storage increase. There is significant decrease in polyene index （PI） index of all the species throughout the storage time, The PI in freshwater fishes decrease by 70% in Tilapia, 90.1% in Belut and 90.9% in Patin, while for marine fishes, PI in Kembung decreases by 67.8%, 85.7% in Kerapu and 65.93% in Tongkol during kept in ice storage. During ice storage, the percentage of EPA, DHA and ALA decrease in Tilapia （55.36%, 13.86% and 75.41%）, Belut （78.55%, 87.74 % and 74.53%） and Patin （82.45%, 40.0% and 82.10%）, respectively. The same result were also observed in the marine fishes where the percentage ofEPA, DHA and ALA decrease in Kembung （94.27%, 49.03% and 88.52%）, in Kerapu （73.03%, 88.18% and 38.73%） and Tongkol （70.05%, 38.24% and 57.14%）, respectively.
