RESUMEN
There has been an increase in interest in the application of ω-3 PUFAs, especially EPA and DHA, in the development of various food products owing to their myriad health benefits. However, most fish oils do not contain more than 30% combined levels of EPA and DHA. In this study, through the urea complexation procedure, the production of EPA and DHA concentrate in their free fatty acids (FFAs) form was achieved from an enzymatic oil extracted from common kilka (Clupeonella cultriventris caspia). To gain the maximum value of EPA and DHA, the response surface methodology (RSM), which is an effective tool to categorize the level of independent variables onto the responses of an experimental process, was also used. Different variables including the urea-fatty acids (FAs) ratio (in the range of 2-6, w/w), the temperature of crystallization (in the range of -24-8 °C), and the time of crystallization (in the range of 8-40 h) were investigated by response surface methodology (RSM) for maximizing the EPA and DHA contents. Following the model validation, the levels of the variables at which the maximum desirability function (0.907 score) was obtained for response variables were 5:1 (urea-FAs ratio), -9 °C (the temperature of crystallization), and 24 h (the time of crystallization). Under these optimal conditions, increases of 2.2 and 4.4 times in the EPA and DHA concentrations were observed, respectively, and an increase in the concentrations of EPA and DHA from 5.39 and 13.32% in the crude oil to 12.07 and 58.36% in the ω-3 PUFA concentrates were observed, respectively. These findings indicate that the urea complexation process is efficient at optimizated conditions.
Asunto(s)
Ácidos Grasos Omega-3 , Aceites de Pescado , Urea , Urea/química , Ácidos Grasos Omega-3/química , Aceites de Pescado/química , Ácidos Docosahexaenoicos/química , Ácidos Docosahexaenoicos/análisis , Ácido Eicosapentaenoico/química , Ácido Eicosapentaenoico/análisis , Animales , CristalizaciónRESUMEN
This study aimed to evaluate the impact of various oil extraction procedures on yield, color properties, fatty acid profile and oxidative stability of common Kilka (Clupeonella cultriventris caspia) oil. The supercritical fluid extraction (SFE) with carbon dioxide, than other techniques (wet reduction, ammonia and enzymatic extractions), showed the highest oil yield (96.94%), the best oxidative and color characteristics, with 0.68 mg KOH/g oil, 2.62 meq O2/kg oil, 6.5 and 5.36 in terms of acid value (AV), peroxide value (PV), yellowness and redness, respectively, and have the highest total of unsaturated fatty acids average (10.33), especially the omega-3 family. Furthermore, the oil obtained by SFE had the best oxidative parameters; AV, PV and thiobarbituric acid values, during the whole 90 days of storage time at 4 °C. Therefore, the SFE is the most effective procedure at obtaining the oil from common Kilka tissue than other methods studied in this research.