Lipid oxidation on tambaqui (Colossoma macropomum) fillets smoked with rosemary (Rosmarinus officinalis)

Abstract

The tambaqui (Colossoma macropomum) is a higher produced native species of fish in Brazil. His flesh has excellent flavor and juiciness due to the presence of high levels of lipids in their composition. This characteristic makes their fillets more susceptible to oxidative reactions that damage lipids, producing taste and odor of rancidity. Natural compounds with antioxidant properties like rosemary (Rosmarinus officinalis) are used to prevent oxidation. The aim of this study was to evaluate the effect of different levels of rosemary addition on lipid oxidation and composition of smoked fillets of tambaqui stored at 10ºC. A completely randomized design with six levels of rosemary addition (zero, 0.1%, 0.2%, 0.4%, 0.8% and 1.6%/kg of fillet) and two times of lipid oxidation evaluation (I and II) was used. The fillets were subjected to a brine containing rosemary, as treatments. The fillets were salted for 20 minutes and smoked during 4 hours. The composition was determined by standard methodology and lipid oxidation by thiobarbituric acid reactive substances (TBARS), the results were expressed as mg of malonaldehyde / kg of fillet, according to the standard curve y = 0.272 x - 0.200 (R² = 0.991). There was significant increase in moisture (P<0.05) caused by the addition of rosemary, while the levels of lipids and TBARS values ​​did not differ (P>0.05) between treatments. It concludes that the addition of rosemary in brine before smoking, until 1.6% level was not effective in controlling lipid oxidation in fillets of tambaqui. Other levels should be tested to determine an optimal value.