Obtención de un Triacilglicérido Estructurado Rico en Ácido gama-linolénico (GLA) por Vía Enzimática

El presente trabajo se desarrolló en tres etapas: (1) reacciones enzimáticas de esterificación con el propósito de preparar un concentrado de GLA a partir del aceite vegetal de Oenothera biennis (EPO). Las variables estudiadas son: relación molar de los sustratos: ácidos grasos de EPO (EPO-FA) y 1-butanol (BtOH); carga de enzima (Candida rugosa); temperatura de operación y adición de tamiz molecular (diferentes tiempos y concentraciones), (2) separación física de las fases de reacción formadas en la etapa anterior: fase butil ésteres y fase rica en GLA, y (3) reacciones enzimáticas de glicerólisis para obtener un triacilglicérido estructurado rico en GLA, monitoreando relación molar de los sustratos (GLA:glicerol), carga de la enzima (Candida antárctica, CALB) y temperatura de operación

Desarrollo de procesos enzimáticos selectivos para aplicaciones nutricionales

76 páginas, 20 figuras. Tesis en español e inglés (Resumen y Conclusiones)Peer reviewe

Lipase-catalyzed glycerolysis of fish oil to obtain diacylglycerols

Copyright (c) 2013 Consejo Superior de Investigaciones Científicas (CSIC)[EN] Diacylglycerols (DAG) rich in n-3 residues were successfully produced by Novozym 435-catalysed glycerolysis of n-3 PUFA rich fish oil. Orbital and magnetic agitations were evaluated in order to minimize mass transfer limitations and thus assure the homogeneity of the reactant mixture. Different temperatures (65, 70, 75, 80, 85 and 90 °C) and speeds (300, 500, 700 and 900 rpm) were tested. Optimal conditions to obtain the highest amount of DAG were: 65 °C, with a substrate molar ratio of 3:1 (oil:glycerol), 500 rpm and 15% enzyme load after 2.5 h, with a yield of 60%.[ES] Diacilglicéridos (DAG) ricos en n-3 fueron producidos en la glicerolisis de aceite de pescado rico en n-3 PUFA catalizada por Novozym 435. Las agitaciones orbital y magnética fueron evaluadas con el propósito de minimizar las limitaciones de transferencia de masa y garantizar la homogeneidad de la mezcla de reactivos. Diferentes temperaturas (65, 70, 75, 80, 85 y 90°C) y velocidades de agitación (300, 500, 700 y 900 rpm) fueron empleadas. Las condiciones óptimas para alcanzar la mayor cantidad de DAG fueron: 65°C, una relación molar de sustratos 3:1 (aceite:glicerol), 500 rpm y 15% de enzima, después de 2.5 h, con un rendimiento de 60%The authors acknowledge a grant from the National Plan of Materials of the Spanish Ministry of Science and Education (ref MAT2007-6662-C02-02), and fellowships for graduate studies of author Baeza (JAE-CSIC grant) and author García (Spanish sabbatical grant).Peer Reviewe

Optimization of structured diacylglycerols production containing ω-3 fatty acids via enzyme-catalysed glycerolysis of fish oil

The main objective of the present work was the production of structured diacylglycerols (DAG) by Novozym 435-catalysed glycerolysis of n-3 PUFA rich fish oil. Different enzyme loads (5, 7, 10, 13 and 15 %, with respect to the total weight of substrates), temperatures (40, 44, 50, 56 and 60 °C) and molar ratios of substrates (1, 1.4, 2, 2.6 and 3, oil/glycerol) were explored by the response surface methodology in order to optimize the reaction system. Temperature showed the highest significant effect (P < 0.05) on the glycerolysis reaction. Good agreement on the experimental data and the second-order polynomial regression was obtained (R 2 = 0.85). Optimal conditions for the production of DAG were established by the model using 15 % enzyme load at 60 °C for a 2:1 (oil/glycerol) substrates molar ratio, reaching a 50 % yield, with 89.37 % n-3 PUFA content, namely, EPA (11.32 %), DPA (8.34 %) and DHA (69.71 %).The authors acknowledge a grant from the National Plan of Materials of the Spanish Ministry of Science and Education (ref MAT2007-6662-C02-02), and fellowships for graduate studies of author Baeza and sabbatical for author García.Peer Reviewe

Kinetics of Transesterification of Safflower Oil to Obtain Biodiesel Using Heterogeneous Catalysis

The kinetics of the transesterification of safflower oil and methanol catalyzed by K2O/NaX was studied and modeled. The influence of the oil-methanol initial molar ratio and amount of catalyst were investigated to achieve a maximum triglycerides conversion (99%) and a final methyl esters content of 94% ± 1. A kineticmodel based on an Eley– Rideal mechanism was found to best fit the experimental data when assuming methanol adsorption as determining step. Other models derived from Langmuir – Hinshelwood – Hougen –Watson (LHHW) mechanisms were rejected based on statistical analysis, mechanistic considerations and physicochemical interpretation of the estimated parameters

Enzyme‐catalysed hydrolysis of phosphatidylcholine for the production of lysophosphatidylcholine

[Background] Production of lysophosphatidylcholine (LPC) via enzyme-catalysed hydrolysis was studied. Three enzymeswereemployed to conduct the reactions at different temperatures. The starting material, phosphatidylcholine (PC), was dispersed inwater (system A) and in ethanol (system B) to define the reaction mixture to carry out the trials.[Results] It was found that themedia employed and the type of biocatalyst (free or immobilized), clearly determine the kinetics of the reactions. PC was well dissolved in ethanol but an opaque emulsion was obtained when it was dissolved in water. Immobilized PLA1 and Novozym 435 were able to convert PC into LPC in ethanol, with yields of 50% and 58.51%, respectively, after 48 h at 50 ¿C. The highest degree of hydrolysis (70%) was reached with Lipase PS after 48 h at 60 ¿C in water.[Conclusions] Both reaction media enabled fairly good yields but water was better. The present work proposes a simple reaction scheme compared with other reports in the literature where different substrates, additives and polar solvents have been employed. LPC has interesting properties as a bioemulsifier, which led us to develop new methods for its production.We thank Professor Garcia's team for the support given during the present work, and the National Council for Science and Technology of Mexico (CONACyT) for financial support through the grant 129334. The authors acknowledge the financial support of the National Plan of Materials of the Spanish Ministry of Science and Education (ref. MAT2007‐6662‐C02‐02), to the CSIC (Spain) for the JAE pre‐doctoral fellowship to author Baeza, and to the Spanish Ministry of Science and Education for a sabbatical grant for author Garcia.Peer Reviewe

Cooking treatments effect on bioactive compounds and antioxidant activity of quintonil (Amaranthus hybridus) harvested in spring and fall seasons

This study investigated the effects of cooking treatments (boiling and steaming) and season of the year (spring and fall) on vitamin C content, total phenolics content (TPC), total flavonoids content (TFC), antioxidant activity and scavenging of nitric oxide (NO•), and superoxide radical (O2–). After cooking, a significant decrease in vitamin C was observed (50 and 48.8% for boiling and 21 and 27.9% for steaming in spring and fall, respectively). TPC and TFC increased during steaming from 145–1480 mg GAE/kg and 348.6–797.2 mg QE/kg, respectively. DPPH values ranged from 2806–3801 μmol TE/kg and was affected by season whereas ORAC ranged from 1231.3–36,167.2 μmol TE/kg and was affected by cooking. The ability to scavenge NO• and O2–, were not affected by neither cooking nor season. However, the inhibition of O2– was higher for quintonil steamed in spring

Lipase-catalysed enrichment of γ-linolenic acid from evening primrose oil in a solvent-free system

The enrichment of γ-linolenic acid (GLA) was carried out in a solvent-free system by lipase-catalysed esterification of free fatty acids from evening primrose oil (EPO-FA) and 1-butanol (BtOH). The lipase employed to conduct this study was a free preparation of Candida rugosa. Variables evaluated were: substrate molar ratio (1:4, 1:6, 1:8, 1:10 and 1:12, EPO-FA:BtOH), temperature (10, 20, 30, 40, 50 and 60 °C), and enzyme loading (5, 10, 15 and 20 %, based on the total weight of substrates). GLA was highly enriched in the non-esterified fatty acid fraction since C. rugosa showed very low selectivity for this fatty acid. We were able to increase the content of GLA to ca. 70 wt.% under the following optimal conditions: 30 °C, 10 % enzyme loading and a 1:10 molar ratio (EPO-FA:BtOH), after 24 h. An additional set of experiments was conducted whereby the amount of water was controlled by addition of molecular sieves to the reaction mixture. The latter experiments produced a higher GLA concentrate (83.74 wt.%), under the optimal conditions described above and by adding 10 % molecular sieves (based on the total weight of substrates) after 36 h.This research was supported by the Rural Development Administration (Korea, project number PJ009247) and CSIC (Spain) for the JAE pre‐doctoral fellowship to author Baeza.Peer Reviewe

Nutritional and bioactive characteristics of Ayocote bean (Phaseolus coccienus L.): An underutilized legume harvested in Mexico

Nutritional composition, content of phenolic compounds and antioxidant properties of the four Mexican varieties of Ayocote beans (Phaseolus coccineus L.) were studied. Ayocote beans were found to be a promising source of proteins, carbohydrates, fibre and minerals. Sucrose (55.6–62.2 g/kg) and stachyose (24–24.4 g/kg) were considered as the major sugar and oligosaccharide, respectively. Glutamic acid was the most abundant amino acid (32.2 to 35.8 g/kg), while cysteine was present at the lowest concentration (2.3–2.4 g/100 kg). Purple variety contains the highest amount of total phenolic compounds (2075.9 mg GAE/kg), total flavonoids (1612.9 mg QE/kg) and total anthocyanins (1193.2 mg CGE/kg). This variety also exhibited the most effective antioxidant activities, which were evaluated by DPPH (17,040 µmol TE/kg) and ORAC (51,620 µmol TE/kg). The results obtained reveal a high potential for wider use of Ayocote bean as a remarkable source of bioactive compounds and health-promoting food