Production of structured triglycerides rich in n-3 polyunsaturated fatty acids by the acidolysis of cod liver oil and caprylic acid in a packed-bed reactor: equilibrium and kinetics

Páez, B. Camacho; Medina, Alfonso Robles; Rubio, F. Camacho; Moreno, Pedro A. González; Grima, E. Molina

doi:10.1016/s0009-2509(02)00050-7

Cited by 56 publications

(58 citation statements)

References 23 publications

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“…In this case the value of k X for the incorporation of PA to TAGs that fits the experimental results is 0.00315 mol/(h×g lipase) for PA (Table 4), which is similar to those obtained in our laboratory for other oils, fatty acids and lipases [31,36,37].…”

Section: Influence Of the Intensity Of Treatment (Iot = Lipase Amountsupporting

confidence: 87%

“…In previous works the results of acidolysis reactions were correlated to an empirical kinetic model [36,37] and to a kinetic model based on the reaction mechanism [38]; in those works was The curve that fits the experimental results in Fig. 1 corresponds to the equation [31,36,39]: and V the reaction mixture volume. Equation (1) was obtained making mass balances to the dispersion reactor and considering that the reaction rate is given by equation:…”

Section: Influence Of Temperature and Solvent Amountmentioning

confidence: 99%

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Production of triacylglycerols rich in palmitic acid at sn-2 position by lipase-catalyzed acidolysis

Jiménez

Esteban

Robles

et al. 2010

Biochemical Engineering Journal

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This paper studies the synthesis of triacylglycerols (TAGs) rich in palmitic acid (PA) at sn-2 position from palm stearin (PS), a vegetable oil highly rich in PA (60%, but only 12.8% of this is located at sn-2 position). These PA rich TAGs were obtained by lipasecatalyzed acidolysis of this oil with free fatty acids (FFAs) highly rich in PA, such as commercial PA (98% PA) and a FFA extract obtained by saponification of PS (60% PA). PA has a melting point of 63 ºC and during the acidolysis reaction the substrates, highly rich in this acid, must remain liquid; therefore high temperatures or solvents must be used. An important objective of this work was to operate without solvent and at the lowest possible temperature. In this acidolysis reaction four factors were firstly studied: type of lipase, temperature, solvent amount and the intensity of treatment (IOT = lipase amount × reaction time/PS amount). The influence of these variables was studied in a stirred tank reactor (STR). The lipases tested were Novozym 435 from Candida antarctica (immobilized on a macroporous acrylic resin), and lipases QLC (immobilized on diatomaceous earth), and QLM (non immobilized), both from Alcaligenes sp., and the one selected was lipase QLC. According to the manufacturer the optimum temperature for this lipase is 65-70 ºC, which allows it to operate without solvent. The best results with lipase QLC (TAGs with 80% PA, both total and at sn-2 position) were obtained with commercial PA, at 65 ºC, a 3:1 FFA/PS molar ratio (1:1 w/w), without solvent and an IOT = 7 g lipase × h/g PS (for example 2.5 g PS, 2.5 g commercial PA, 0.75 g lipase and 24 h). These results were the basis for establishing the operational conditions to obtain PA rich TAGs with the lipase immobilized in a packed bed reactor (PBR), operating by recirculation of the reaction mixture through the lipase bed. In this system TAGs with 75% PA were obtained at an IOT = 8 g lipase × h/g PS. This result and the apparent kinetic constants obtained in both reactors show that the reaction rate is lower in the PBR than in the STR. Subsequently, PA enriched TAGs were separated from FFAs by two procedures: the first one at room temperature and in presence of hexane and the second one at 65 ºC and without hexane. Using the first procedure, 95% of TAGs in the acidolysis reaction mixture were recovered with a purity of 99%. Using the second one, 98% pure TAGs were obtained with a recovery yield of 80%. Therefore, these highly rich PA TAGs can be obtained by acidolysis of PS and PA rich FFAs in solvent-free media, and then these TAGs also can be purified to 98% in absence of hexane, using only a hydroethanolic KOH solution.3

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Section: Influence Of the Intensity Of Treatment (Iot = Lipase Amountsupporting

confidence: 87%

Section: Influence Of Temperature and Solvent Amountmentioning

confidence: 99%

Production of triacylglycerols rich in palmitic acid at sn-2 position by lipase-catalyzed acidolysis

Jiménez

Esteban

Robles

et al. 2010

Biochemical Engineering Journal

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“…Fractions corresponding to each glyceride type were scraped from the plates and methylated by direct transesterification with acetyl chloride/methanol (1:20) according to the method of Lepage and Roy [16]. These methyl esters were analyzed by capillary GC following the procedure described in [17]. Table 3 shows the molar fraction of caprylic acid incorporated into the triglycerides as a function of the amount of water added and the reaction time.…”

Section: Identification Of Reaction Products and Estimation Of The Momentioning

confidence: 99%

Modeling the effect of free water on enzyme activity in immobilized lipase-catalyzed reactions in organic solvents

Páez

Medina

Rubio

et al. 2003

Enzyme and Microbial Technology

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The influence of water content on the lipase-catalyzed acidolysis of triolein (glycerol-trioleate, TO) and caprylic acid (CA) in hexane, using an immobilized enzyme was studied. An adequate water content (R W ) ranged from near zero to 0.1 g of water/g of dry enzyme. Over these values there was a decrease in the rate of incorporation of CA into triglyceride. This decrease was attributed to the progressive flooding of the carrier's pores, in which the enzyme was immobilized. The flooding reduced the number of the enzyme molecules at the water-hexane interface and therefore, hindered the accessibility of the hydrophobic substrates (TO and CA) to the enzyme. A simple physical model based on a characterization of the immobilized enzyme particle by mercury porosimetry was developed. The model agreed well with both the experimental data and the prior published data. The model may partly explain the observed inhibition when using low molecular weight alcohols and carboxylic acids in immobilized lipase-catalyzed processes.

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“…The IOT is the lipase amount × reaction time/POS amount (limiting reagent) and it is a useful parameter for the scaling up of enzymatic reactions [32,27]. The habitually used lipase amount ranges between 10% and 25% of the amount of reaction mixture.…”

Section: Influence Of the Intensity Of Treatment (Iot)mentioning

confidence: 99%

Production of triacylglycerols rich in palmitic acid at position 2 as intermediates for the synthesis of human milk fat substitutes by enzymatic acidolysis

Jiménez

Esteban

Robles

et al. 2010

Process Biochemistry

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This paper studies the synthesis of triacylglycerols (TAGs) rich in palmitic acid (PA) at position 2, from palm oil stearin (POS), a vegetable oil highly rich in this acid (60%). The developed process consists of two steps: (1) obtaining PA enriched free fatty acids (FFAs), and (2) enrichment of POS in PA by acidolysis of this oil with PA enriched FFAs, catalyzed by lipase Novozym 435. In step (1) two PA enriched FFA mixtures were obtained: one by saponification of POS, and a PA concentrate (75.1% PA) obtained by crystallization at low temperature in solvents. The latter was obtained carrying out two crystallizations in acetone at -24 and -20 ºC, from which PA was recovered in the solid phases with a total yield of 84%. These PA enriched FFA mixtures were used in step (2) of acidolysis of POS, along with commercial PA (98% PA). In this acidolysis step four factors were studied: temperature, hexane/reaction mixture ratio, FFA/POS molar ratio and the intensity of treatment (IOT = lipase amount × reaction time/POS amount). The best results (TAGs with 79% PA and 75% PA at position 2) were obtained with commercial PA, at 37 ºC, 10 mL hexane/g reaction mixture, a FFA/POS molar ratio 3:1 (1:1 w/w) and an IOT = 9.6 g lipase × h/g POS (for example 48 h, 10 g lipase and 50 g POS). PA enriched TAGs were purified neutralizing the FFAs by KOH hydroethanolic solutions and extracting the TAGs with hexane. In this way 99% pure acylglycerols (TAG+DAG) were obtained; the recovery yield of this purification step was 95%. The experiments carried out with POS demonstrated that it is possible to use only this oil (60% PA, 23% PA at position 2) as a source of PA to obtain a TAG with 70.7% PA and 70.5% PA at position 2. This process consists of four steps:(1) saponification of POS, (2) crystallization of FFAs to obtain PA enriched FFAs (75.1% PA), (3) acidolysis of POS with these FFAs, catalyzed with Novozym 435, to produce PA enriched TAGs at position 2 (70.5% PA) and (4) purification of TAGs to obtain approximately 95% purity and yield. These PA enriched TAGs could be used to obtain structured TAGs rich in PA at position 2 and in oleic acid at positions 1 and 3 (OPO), which is the principal TAG of human milk fat.

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Production of structured triglycerides rich in n-3 polyunsaturated fatty acids by the acidolysis of cod liver oil and caprylic acid in a packed-bed reactor: equilibrium and kinetics

Cited by 56 publications

References 23 publications

Production of triacylglycerols rich in palmitic acid at sn-2 position by lipase-catalyzed acidolysis

Production of triacylglycerols rich in palmitic acid at sn-2 position by lipase-catalyzed acidolysis

Modeling the effect of free water on enzyme activity in immobilized lipase-catalyzed reactions in organic solvents

Production of triacylglycerols rich in palmitic acid at position 2 as intermediates for the synthesis of human milk fat substitutes by enzymatic acidolysis

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