RESUMEN
This study aimed to selectively enrich stearidonic acid (SDA) together with γ-linolenic acid (GLA) in Echium plantagineum oil by urea complexation. The complexation process at room temperature was carried out replacing common organic solvents, such as hexane and ethanol, by alternative compounds, included in Green Solvent and Food Grade categories, adapting this process towards the principles of Green Chemistry. This substitution was also intended to avoid the generation of the toxic compound ethyl carbamate. Among all the solvents studied, the mixture propionic acid and α-pinene provided the best results, leading to a final product comprised of â¼99% of PUFA, with â¼45% SDA (â¼14% in the original oil), and without apparition of ethyl carbamate. The procedure was tested on other raw materials (salmon and microalgae oils). The solvent was efficiently recuperated from the liquid phase (â¼87% recovery) and reutilized once with almost identical results.
Asunto(s)
Ácidos Grasos Omega-3 , Uretano , Ácidos Grasos Omega-3/química , Aceites de Plantas/química , Semillas/química , Solventes , Urea/química , Uretano/análisisRESUMEN
Concentration of polyunsaturated fatty acids ethyl esters (FAEE) by urea complexation from Echium oil was studied. Different variables involved in the process were investigated: amount and particle size of urea, solvent volume and ratio (hexane/ethanol), load of FAEE and reaction time. Hence, the main goal was to optimize SDA concentration (%) and yield (%) of stearidonic acid (SDA, 18:4 ω-3) and other bioactive FAEE. Similar behaviors were observed in fractionation between α-linolenic (ALA)-linoleic (LA), and γ-linolenic (GLA)-stearidonic (SDA) acids, attributed to similarities on their chemical structures, due to the position of the double bonds. At laboratory scale, the optimal conditions were 3 g urea (powder), 3.6 mL of hexane, 0.54 mL of ethanol and 800 mg of FAEE, during 20 h at 25°C. A scaling-up at pilot plant was carried out twice, obtaining more than 100 g of a final product, with ~29% SDA concentration and ~78% yield. Besides, after two washings with water, ethyl carbamates (urethanes) were not detected in the final product. Thus, a mixture of FAEE with about 85% of bioactive fatty acids with anti-inflammatory properties was obtained, which can be a high added-value product with great potential for the synthesis of functional lipids and nutraceuticals.
Asunto(s)
Echium/química , Ácidos Grasos Omega-3/análisis , Aceites de Plantas/química , Urea/química , Antiinflamatorios , Ésteres/análisis , Ésteres/química , Etanol/química , Ácidos Grasos Omega-3/química , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/química , Hexanos/química , Tamaño de la Partícula , Solventes/química , Factores de Tiempo , Uretano , AguaRESUMEN
The aim of this work was to produce diacylglycerols (DAG) and monoacylglycerols (MAG) with a high content of polyunsaturated fatty acids (PUFA). Rhizomucor miehei lipase mediated-hydrolysis of sardine oil was conducted at several water activities. The system was mechanistically modeled to predict the time evolution of the concentration of triacylglycerols, DAG, MAG and free fatty acids (FFA) and the concentration of saturated, mono- and polyunsaturated fatty acids. The release of the first fatty acid from the triacylglycerol was independent on the unsaturation degree. Contrary, the hydrolysis of the second one was highly affected by the degree of unsaturation, PUFA being the fatty acids that showed the highest resistance to hydrolysis. MAG percentage was maximum (7mol%) at lower water activities, while DAG content was favored at higher water activities (35mol%), achieving a 2-fold concentration of DHA.
Asunto(s)
Aceites de Pescado/metabolismo , Lipasa/metabolismo , Animales , Ácidos Grasos , Ácidos Grasos Insaturados , Peces , Glicéridos , Hidrólisis , Rhizomucor , TriglicéridosRESUMEN
The concentration of polyunsaturated fatty acids by formation of urea adducts from three different sources was studied to elucidate the formation of ethyl carbamates in the course of these procedures. Two different methodologies were performed: with ethanol at high temperature and with hexane/ethanol mixtures at room temperature. It was proved that the amount of urethanes generated at high temperature was higher than at room temperature. Besides, subsequent washing steps of the PUFA fraction with water were efficient to remove the urethanes from the final products. The methodology at room temperature with 0.4mL ethanol and 3g urea provided good relationship between concentration and yield of the main bioactive PUFA, with the lowest formation of ethyl carbamates in the process.
Asunto(s)
Ácidos Grasos Insaturados/química , Urea/química , Uretano/químicaRESUMEN
In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO2 membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO2 nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration. INDUSTRIAL RELEVANCE: The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced.