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1.
J Oleo Sci ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39019620

RESUMO

With increases in consumer demand for fried foods in Japan over the last several decades, the consumption of frying oil has also steadily increased. Fryers used in restaurants to cook large quantities of food are typically cleaned using neutral kitchen detergents at the end of the day after removing the oil from the tank. However, significant amounts of debris can remain in the fryer after cleaning, possibly accelerating oil deterioration and thus reducing the quality of the fried foods. In this study, debris obtained from fryer tanks used in actual restaurants was assessed using scanning electron microscopy-energy dispersive X-ray spectroscopy together with Fourier transform infrared spectroscopy, and were determined to comprise polymerized oil and carbonized organic matter. Experiments using artificially prepared debris confirmed that these materials increased the acid value (AV) of frying oil. Trials in two restaurants serving similar amounts of fried chicken, French fries and doughnuts examined the effects of cleaning the fryer with either an alkaline detergent or a neutral kitchen detergent on debris removal and oil life. The alkaline detergent was found to completely remove debris while the neutral detergent left significant amounts of debris. After cleaning, the fryers were operated with new oil as usual and the deterioration of this oil was monitored by assessing the color difference, AV, carbonyl value and peroxide value. These indices increased 1.3 to 2.0 times faster in the case that the neutral kitchen detergent was used, suggesting that cleaning fryer tanks with an alkaline detergent could contribute to extending the lifetime of frying oil, reducing food losses and thus achieving sustainable development goals.

2.
J Oleo Sci ; 73(1): 55-63, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38171731

RESUMO

Highly pure 2,3-dioleoyl-1-O-alkyl glyceryl ether (DOGE), whose 1-position is a lipase-tolerant ether bond, was chemically synthesized and its detailed regioselectivity and acyl transfer were confirmed. During ethanolysis using immobilized Candida antarctica lipase B (CAL-B) with DOGE as the substrate, monooleoyl-1-O-alkyl glyceryl ethers (MOGEs) and a few 1-alkyl glyceryl ethers were formed upon consumption of the substrate. The structure of MOGE was confirmed using nuclear magnetic resonance spectroscopy and only the isomer of 2-MOGE was formed, indicating that CAL-B has complete α- regiospecificity. During ethanolysis, 3-MOGE was formed via acyl migration. These results indicate that the formation of 1-alkyl glyceryl ethers is not due to the imperfect regiospecificity of CAL-B, but rather due to ethanolysis of the formed 3-MOGE. The ethanolysis rate at the 3-α-position of DOGE was faster and the rate of acyl transfer was slightly slower for chain lengths greater than 14. These results show for the first time that both deacylation at the 3-position and acyl migration from the 2- to 3-position are affected by the structure of 1-position.


Assuntos
Etanol , Éteres de Glicerila , Etanol/química , Lipase/química , Proteínas Fúngicas/química , Enzimas Imobilizadas/química
3.
Front Nutr ; 9: 970837, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36185659

RESUMO

The Röse-Gottlieb method is one of the most widely used methods for extracting lipids from milk samples. However, we found that lipid recovery from liquid infant formula and human breast milk was lower than expected. Better lipid recovery from these liquid matrices was obtained by solid phase extraction using silica gel; ~10% more could be recovered from liquid infant formula and ruminant milk, and 25% more from human breast milk. However, the method is not recommended for lipid extraction from dried whole milk powders.

4.
RSC Adv ; 12(17): 10619-10624, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35425022

RESUMO

Racemic 1-phenylethanols were converted into enantiopure (R)-1-phenylethanols via a chemoenzymatic process in which manganese oxide driven oxidation was coupled with enzymatic biotransformation by compartmentalization of the reactions, although the two reactions conducted under mixed conditions are not compatible due to enzyme deactivation by Mn ions. Achiral 1-phenylethanol is oxidized to produce acetophenone in the interior chamber of a polydimethylsiloxane thimble. The acetophenone passes through the membrane into the exterior chamber where enantioselective biotransformation takes place to produce (R)-1-phenylethanol with an enantioselectivity of >99% ee and with 96% yield. The developed sequential reaction could be applied to the deracemization of a wide range of methyl- and chloro-substituted 1-phenylethanols (up to 93%, >99% ee). In addition, this method was applied to the selective hydroxylation of ethylbenzene to afford chiral 1-phenylethanol.

5.
J Agric Food Chem ; 67(29): 8191-8196, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31282662

RESUMO

Conversion of free fatty acids into monoacylglycerol gives rise to new structural properties, particularly amphipathic property. Therefore, monoacylglycerols are widely used in pharmaceutical and food industries and are also reported to facilitate better absorption into the human body. A functional fatty acid when transformed into a monoacylglycerol will possibly conserve both the original functionality and amphipathic property. The compound 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was generated from oleic acid by Pseudomonas aeruginosa PR3 and was known to contain antimicrobial activities against a broad range of food-borne and plant pathogenic bacteria. Here, we attempted to convert DOD into its monoacylglycerol form using lipase for producing an amphipathic antibacterial agent. Consequently, the monoacylglycerol of DOD (DOD-MAG) was successfully produced by coincubating DOD, glycerol, and lipase at 30 °C. The maximum conversion yield reached 70% after 12 h of incubation. Antibacterial activity of DOD-MAG was enhanced by 8 times from the original activity of DOD against food-borne bacteria.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Monoglicerídeos/química , Ácidos Oleicos/química , Ácidos Oleicos/farmacologia , Pseudomonas aeruginosa/química , Antibacterianos/metabolismo , Microbiologia de Alimentos , Ácidos Oleicos/metabolismo , Pseudomonas aeruginosa/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
6.
Artigo em Inglês | MEDLINE | ID: mdl-28684067

RESUMO

Plasma n-3 fatty acids are important as the supplying pool of n-3 fatty acids to various tissues including the brain, although the relationship between dietary n-3 fatty acids and their molecular species in the plasma are not fully clarified. We investigated the intestinal absorption of docosahexaenoic acid (DHA) derived from fish roe phospholipid (Roe-PL) and compared it with fish oil triacylglycerol and free DHA using unanesthetized lymph-cannulated rats. The DHA absorption from intraduodenally administered three samples were not significantly different, whereas Roe-PL administration resulted in a significantly higher level of DHA in the phospholipid fraction than the other two samples administrations. DHA in Roe-PL at the sn-2 position was less hydrolyzed by pancreatin than by purified phospholipase A2 in vitro and simultaneous administration of free DHA and lysophosphatidylcholine did not produce the same results as the Roe-PL administration. Our results indicate that dietary DHA-containing phospholipid is effective to increase the systemic DHA incorporated into phospholipids via intestinal absorption and biosynthesis.


Assuntos
Ácidos Docosa-Hexaenoicos/metabolismo , Óleos de Peixe/farmacologia , Absorção Intestinal/efeitos dos fármacos , Linfa/metabolismo , Lisofosfatidilcolinas/farmacologia , Triglicerídeos/farmacologia , Animais , Masculino , Ratos , Ratos Wistar
7.
J Oleo Sci ; 66(6): 585-590, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28515379

RESUMO

An indirect enzymatic analysis method for the quantification of fatty acid esters of 2-/3-monochloro-1,2-propanediol (2/3-MCPD) and glycidol was developed, using the deuterated internal standard of each free-form component. A statistical method for calibration and quantification of 2-MCPD-d5, which is difficult to obtain, is substituted by 3-MCPD-d5 used for calculation of 3-MCPD. Using data from a previous collaborative study, the current method for the determination of 2-MCPD content using 2-MCPD-d5 was compared to three alternative new methods using 3-MCPD-d5. The regression analysis showed that the alternative methods were unbiased compared to the current method. The relative standard deviation (RSDR) among the testing laboratories was ≤ 15% and the Horwitz ratio was ≤ 1.0, a satisfactory value.


Assuntos
Calibragem/normas , Ensaios Enzimáticos/métodos , Compostos de Epóxi/análise , Ésteres/análise , Ácidos Graxos/análise , Análise de Alimentos/métodos , Glicerol/análogos & derivados , Propanóis/análise , Gorduras Insaturadas na Dieta/análise , Glicerol/análise , Análise de Regressão
8.
J Oleo Sci ; 65(11): 923-928, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27733742

RESUMO

Crude soybean and rapeseed oils were subjected to the method to determine FA distributions in TAG using Candida antarctica lipase B, giving similar results to those for refined oils. Minor components in crude oils, such as percentages of FFA or phospholipids were indicated not to affect 1(3)-selective transesterification by the lipase and FA compositional analysis of the resulting 2-MAG fraction significantly. Phospholipids were confirmed not to contaminate the 2-MAG fraction. Oxidized soybean oil with a PV of 10 meq/kg also gave similar results to the ones for refined oil. The method was confirmed to be applicable for crude oils and oxidized oils with a PV smaller than 10 meq/kg without prior purification of TAG.


Assuntos
Ácidos Graxos/análise , Proteínas Fúngicas/química , Lipase/química , Óleos de Plantas/análise , Óleo de Soja/análise , Triglicerídeos/análise , Biocatálise , Brassica rapa , Candida , Esterificação , Etanol/química , Estrutura Molecular , Monoglicerídeos/análise , Ácido Oleico/química , Óleo de Brassica napus , Glycine max
9.
J Oleo Sci ; 65(7): 557-68, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27321120

RESUMO

A collaborative study was conducted to evaluate an indirect enzymatic method for the analysis of fatty acid esters of 3-monochloro-1,2-propanediol (3-MCPD), 2-monochloro-1,3-propanediol (2-MCPD), and glycidol (Gly) in edible oils and fats. The method is characterized by the use of Candida rugosa lipase, which hydrolyzes the esters at room temperature in 30 min. Hydrolysis and bromination steps convert esters of 3-MCPD, 2-MCPD, and glycidol to free 3-MCPD, 2-MCPD, and 3-monobromo-1,2-propanediol, respectively, which are then derivatized with phenylboronic acid, and analyzed by gas chromatography-mass spectrometry. In a collaborative study involving 13 laboratories, liquid palm, solid palm, rapeseed, and rice bran oils spiked with 0.5-4.4 mg/kg of esters of 3-MCPD, 2-MCPD, and Gly were analyzed in duplicate. The repeatability (RSDr) were < 5% for five liquid oil samples and 8% for a solid oil sample. The reproducibility (RSDR) ranged from 5% to 18% for all oil samples. These RSDR values were considered satisfactory because the Horwitz ratios were ≤ 1.3% for all three analytes in all oil samples. This method is applicable to the quantification of 3-MCPD, 2-MCPD, and Gly esters in edible oils.


Assuntos
Compostos de Epóxi/análise , Glicerol/análogos & derivados , Lipase/metabolismo , Óleos de Plantas/química , Plantas Comestíveis/química , alfa-Cloridrina/análise , Candida/enzimologia , Compostos de Epóxi/metabolismo , Glicerol/análise , Glicerol/metabolismo , alfa-Cloridrina/metabolismo
10.
Lipids ; 51(8): 913-22, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27023203

RESUMO

The regioisomers of the di- and mono-oleate of monochloropropanediol (MCPD) have been synthesized and subsequently hydrolyzed with pancreatic lipase and pancreatin to estimate the intestinal digestion and absorption of these compounds after their intake. The hydrolysates were analyzed by HPLC using a corona charged aerosol detection system, which allowed for the separation and detection of the different regioisomers of the MCPD esters. The hydrolysates were also analyzed by GC-MS to monitor the free MCPD. The results indicated that the two acyl groups of 2-MCPD-1,3-dioleate were smoothly hydrolyzed by pancreatic lipase and pancreatin to give free 2-MCPD. In contrast, the hydrolysis of 3-MCPD-1,2-dioleate proceeded predominantly at the primary position to produce 3-MCPD-2-oleate. 2-MCPD-1-oleate and 3-MCPD-1-oleate were further hydrolyzed to free 2- and 3-MCPD by pancreatic lipase and pancreatin, although the hydrolysis of 3-MCPD-2-oleate was 80 % slower than that of 3-MCPD-1-oleate. The intestinal absorption characteristics of these compounds were evaluated in vitro using a Caco-2 cell monolayer. The results revealed that the MCPD monooleates, but not the MCPD dioleates, were hydrolyzed to produce the free MCPD in the presence of the Caco-2 cells. The resulting free MCPD permeated the Caco-2 monolayer most likely via a diffusion mechanism because their permeation profiles were independent of the dose. Similar permeation profiles were obtained for 2- and 3-MCPDs.


Assuntos
Ésteres/análise , Glicerol/análogos & derivados , Mucosa Intestinal/metabolismo , Lipase/metabolismo , Pancreatina/metabolismo , alfa-Cloridrina/química , Células CACO-2 , Cromatografia Líquida de Alta Pressão , Ésteres/química , Cromatografia Gasosa-Espectrometria de Massas , Glicerol/química , Humanos , Hidrólise , Absorção Intestinal
11.
J Oleo Sci ; 65(4): 291-302, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26972465

RESUMO

The positional distributions of fatty acids (FAs) in milk fat containing short- and medium-chain FAs were analyzed by sn-1(3)-selective transesterification of triacylglycerols (TAGs) with ethanol using immobilized Candida antarctica lipase B (CALB), in a collaborative study conducted by 10 laboratories. The mean C4:0, C6:0, and C8:0 FA contents, when analyzed as propyl esters (PEs) using gas chromatography (GC) with a DB-23 capillary column, were found to be 3.0, 2.0, and, 1.3 area%, respectively. Their reproducibility standard deviations were 0.33, 0.18, and 0.19, respectively. The mean C4:0, C6:0, and C8:0 contents at the sn-2 position were 0.3, 0.4, and 1.0 area%, respectively. Their reproducibility standard deviations were 0.17, 0.11, and 0.19, respectively. The reproducibility standard deviations of C4:0, C6:0, and C8:0 FAs at the sn-2 position were either the same as or smaller than those for milk fat, although the FA contents at the sn-2 position were smaller than those in the milk fat. Therefore, it was concluded that the CALB method for estimating the regiospecific distribution is applicable to TAGs containing short- and medium-chain FAs. When estimating the short-chain (SC) FA contents in fats and oils by GC, it is better to analyze SCFAs as PEs or butyl esters, and not as methyl esters, in order to prevent loss of SCFAs during the experimental procedure because of their volatility and water solubility. This study also revealed that the stationary phase of the GC capillary column affected the flame ionization detector (FID) response of SCFAs. The theoretical FID correction factor (MWFA / active carbon number / atomic weight of carbon) fitted well with the actual FID responses of C4:0-C12:0 FAs when they were analyzed as PEs using a DB-23 column; however, this was not the case when the GC analysis was performed using wax-type columns.


Assuntos
Ensaios Enzimáticos/métodos , Gorduras/química , Ácidos Graxos/análise , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Leite/química , Animais , Enzimas Imobilizadas , Etanol , Ácidos Graxos Voláteis/análise , Colaboração Intersetorial , Reprodutibilidade dos Testes , Triglicerídeos
12.
J Oleo Sci ; 64(12): 1251-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26632945

RESUMO

The recovery of short-chain fatty acids (FAs) in milk fat (MF) is improved when the analysis of the FA composition of MF by gas chromatography (GC) is conducted with the propyl or butyl ester derivatives, instead of the methyl esters. However, this approach complicates the detection of minor FAs, such as the minor positional isomers of 16:1, which represent <0.2% of the total content. In addition, the standards of these minor esters are not commercially available. In this study, with the aim to identify minor FAs, the fatty acid propyl esters (FAPEs) of MF were fractionated by Ag-ion solid phase extraction (Ag(+)-SPE) and analyzed by GC using a DB-23 capillary column. FAPEs were successfully fractionated mainly according to the degree of unsaturation by adjusting the elution conditions of the Ag(+)-SPE, and the minor FAPEs were easily determined without the aid of standard compounds. For example, by comparison of the GC profile of the saturated Ag(+)-SPE fraction with that of the original MF, minor FAs, such as iso-, anteiso-, and saturated FAs of 15:0 and 17:0, were expected to be eluted in this order. In addition, 16:1 propyl ester was co-eluted with iso 17:0 propyl ester under the GC conditions used in this study, as confirmed by the detection of the corresponding molecular ions (296 and 312, respectively) by GC-MS. Moreover, 9c,11t-conjugated linoleic acid was found to elute between 18:3 and 20:0. To the best of our knowledge, this is the first report suggesting that the peak observed before that of cis-12:1 corresponds to trans-12:1. In conclusion, Ag(+)-SPE fractionation of FAPEs contributed to the identification of minor FAs in MF without the use of standard compounds.


Assuntos
Cromatografia Gasosa/métodos , Ésteres/isolamento & purificação , Gorduras/química , Ácidos Graxos Voláteis/isolamento & purificação , Leite/química , Extração em Fase Sólida/métodos , Animais , Cátions/química , Bovinos , Fracionamento Químico/métodos , Ácidos Graxos Voláteis/análise , Cromatografia Gasosa-Espectrometria de Massas , Isomerismo , Ácidos Linoleicos Conjugados/análise , Ácidos Linoleicos Conjugados/isolamento & purificação , Prata
13.
J Oleo Sci ; 64(11): 1193-205, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26521812

RESUMO

The positional distributions of fatty acids (FAs) in fats and oils are principally analyzed by selectively transesterifying the target triacylglycerols (TAGs) at the 1(3) position using Pseudozyma (Candida) antarctica lipase, followed by recovering the resulting 2-monoacylglycerols (MAGs) by chromatography. FA compositions were measured by gas chromatography (GC) after methylating target TAGs and 2-MAGs. The method was collaboratively evaluated by 12 laboratories by analyzing the positional FA distributions in soybean, palm, and sardine oils. The maximum reproducibility relative standard deviations for the major FAs and those at the sn-2 positions of soybean, palm, and sardine oils were 4.41% and 3.92% (18:3n-3), 4.48% and 3.82% (18:0), and 8.93 and 8.24% (14:0), respectively. The values at the sn-2 position were always low. Therefore, these results indicated that the variations were mainly caused by the FA analysis procedure, i.e., the methylation and GC analyses, rather than the enzymatic transesterification and chromatography utilized to prepare 2-MAGs from the target oil.


Assuntos
Ensaios Enzimáticos/métodos , Ácidos Graxos/análise , Óleos de Peixe/química , Proteínas Fúngicas/química , Lipase/química , Óleos de Plantas/química , Óleo de Soja/química , Triglicerídeos/química , Cromatografia Gasosa , Esterificação , Monoglicerídeos , Óleo de Palmeira
14.
J Oleo Sci ; 64(10): 1057-64, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26369594

RESUMO

We developed a novel, indirect enzymatic method for the analysis of fatty acid esters of 3-monochloro-1,2-propanediol (3-MCPD), 2-monochloro-1,3-propanediol (2-MCPD), and glycidol (Gly) in edible oils and fats. Using this method, the ester analytes were rapidly cleavaged by Candida rugosa lipase at room temperature for 0.5 h. As a result of the simultaneous hydrolysis and bromination steps, 3-MCPD esters, 2-MCPD esters, and glycidyl esters were converted to free 3-MCPD, 2-MCPD, and 3-monobromo-1,2-propanediol (3-MBPD), respectively. After the addition of internal standards, the mixtures were washed with hexane, derivatized with phenylboronic acid, and analyzed by gas chromatography-mass spectrometer (GC-MS). The analytical method was evaluated in preliminary and feasibility studies performed by 13 laboratories. The preliminary study from 4 laboratories showed the reproducibility (RSD R ) of < 10% and recoveries in the range of 102-111% for the spiked 3-MCPD and 2-MCPD in extra virgin olive (EVO) oil, semi-solid palm oil, and solid palm oil. However, the RSDR and recoveries of Gly in the palm oil samples were not satisfactory. The Gly content of refrigerated palm oil samples decreased whereas the samples at room temperature were stable for three months, and this may be due to the depletion of Gly during cold storage. The feasibility studies performed by all 13 laboratories were conducted based on modifications of the shaking conditions for ester cleavage, the conditions of Gly bromination, and the removal of gel formed by residual lipase. Satisfactory RSDR were obtained for EVO oil samples spiked with standard esters (4.4% for 3-MCPD, 11.2% for 2-MCPD, and 6.6% for Gly).


Assuntos
Ensaios Enzimáticos/métodos , Compostos de Epóxi/análise , Glicerol/análogos & derivados , Azeite de Oliva/química , Óleos de Plantas/química , Propanóis/análise , alfa-Cloridrina/análise , Candida/enzimologia , Ésteres , Estudos de Viabilidade , Cromatografia Gasosa-Espectrometria de Massas , Glicerol/análise , Halogenação , Lipase , Óleo de Palmeira , Temperatura
15.
J Oleo Sci ; 64(6): 617-24, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26028327

RESUMO

It is revealed that binding position of fatty acid in triacylglycerol (TAG) deeply relates to the expression of its function. Therefore, we investigated the binding positions of individual trans-octadecenoic acid (trans-C18:1) positional isomers, known as unhealthy fatty acids, on TAG in partially hydrogenated canola oil (PHCO), milk fat (MF), and beef tallow (BT). The analysis was carried out by the sn-1(3)-selective transesterification of Candida antarctica Lipase B and by using a highly polar ionic liquid capillary column for gas chromatography-flame ionization detection. Trans-9-C18:1, the major trans-C18:1 positional isomer, was selectively located at the sn-2 position of TAG in PHCO, although considerable amounts of trans-9-C18:1 were also esterified at the sn-1(3) position. Meanwhile, trans-11-C18:1, the major isomer in MF and BT, was preferentially located at the sn-1(3) position. These results revealed that the binding position of trans-C18:1 positional isomer varies between various fats and oils.


Assuntos
Gorduras/química , Ácidos Graxos Monoinsaturados/química , Ácidos Esteáricos/química , Triglicerídeos/química , Animais , Sítios de Ligação , Bovinos , Cromatografia Gasosa/métodos , Ionização de Chama , Hidrogenação , Isomerismo , Leite/química , Óleo de Brassica napus , Ácidos Graxos trans/química
16.
Lipids ; 50(5): 483-92, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25860691

RESUMO

Euglena gracilis produces wax ester under hypoxic and anaerobic culture conditions with a net synthesis of ATP. In wax ester fermentation, fatty acids are synthesized by reversing beta-oxidation in mitochondria. A major species of wax ester produced by E. gracilis is myristyl myristate (14:0-14:0Alc). Because of its shorter carbon chain length with saturated compounds, biodiesel produced from E. gracilis wax ester may have good cold flow properties with high oxidative stability. We reasoned that a slight metabolic modification would enable E. gracilis to produce a biofuel of ideal composition. In order to produce wax ester with shorter acyl chain length, we focused on isozymes of the enzyme 3-ketoacyl-CoA thiolase (KAT), a condensing enzyme of the mitochondrial fatty acid synthesis pathway in E. gracilis. We performed a gene silencing study of KAT isozymes in E. gracilis. Six KAT isozymes were identified in the E. gracilis EST database, and silencing any three of them (EgKAT1-3) altered the wax ester amount and composition. In particular, silencing EgKAT1 induced a significant compositional shift to shorter carbon chain lengths in wax ester. A model fuel mixture inferred from the composition of wax ester in EgKAT1-silenced cells showed a significant decrease in melting point compared to that of the control cells.


Assuntos
Acetil-CoA C-Aciltransferase/genética , Euglena gracilis/enzimologia , Ácidos Mirísticos/química , Ácidos Mirísticos/metabolismo , Acetil-CoA C-Aciltransferase/metabolismo , Clonagem Molecular , Euglena gracilis/genética , Fermentação , Inativação Gênica , Isoenzimas/genética , Isoenzimas/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Temperatura de Transição
17.
Springerplus ; 1(1): 67, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23420098

RESUMO

Conjugated linoleic acid l-menthyl ester was hydrolyzed in water by the lipase from Candida rugosa with the addition of an organic solvent. The degree of hydrolysis (yield) greatly improved when a tertiary alcohol, such as t-butyl alcohol, was added. However, the addition of a less polar solvent, such as hexane, decreased the degree of hydrolysis, and some water-miscible solvents, such as acetone, caused inactivation of the lipase. With the addition of t-butyl alcohol, the reaction mixture formed a one- or two-phase system, and the mixing ratio of substrates and t-butyl alcohol determined the number of phases. Although the degree of hydrolysis at 10 d was higher in the one-phase system, the initial reaction rate was generally lower. Meanwhile, the reaction was much faster in the two-phase system while maintaining a moderate degree of hydrolysis.

18.
J Oleo Sci ; 60(8): 445-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21768746

RESUMO

Commercially available conjugated linoleic acid (CLA) is a mixture of two main isomers. Fractionation of the two isomers was performed by a lipase-catalyzed esterification of CLA with L-menthol. In this study, a GC analytical method was developed to simultaneously determine the degree of esterification and fatty acid (FA) compositions of CLA in the free fatty acid (FFA) and ester forms without separation of the FFA and the ester. The methylation of the oil phase of the reaction mixture was performed using trimethylsilyldiazomethane in a mixture of toluene/methanol. Only FFA was quantitatively methylated, whereas the other compounds were little changed. A GC analysis using a polar column was performed to simultaneously determine the degree of esterification and the fatty acid compositions.


Assuntos
Cromatografia Gasosa/métodos , Ésteres/química , Ácidos Graxos/análise , Ácidos Linoleicos Conjugados/química , Metilação , Fatores de Tempo
19.
N Biotechnol ; 28(1): 7-13, 2011 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-20709631

RESUMO

Docosahexaenoic acid (DHA)-rich oil has been industrially produced by selective hydrolysis of tuna oil with a lipase that acts weakly on DHA. The free fatty acids (FFAs) generated in this process as by-products contain a high DHA concentration (46wt%) but are treated as industrial waste. This study attempted to reuse these by-product FFAs using a one-pot process, and succeeded in producing triacylglycerols (TAGs) through the esterification of the by-product FFAs with glycerol using immobilized Rhizomucor miehei lipase. Regiospecific analysis of the resulting TAGs showed that the content of DHA at the sn-1(3) position (51.7mol%) was higher than the content of DHA at the sn-2 position (17.3mol%). The DHA distribution in TAGs synthesized in this study was similar to the DHA distribution in TAGs from seal oil.


Assuntos
Química Orgânica/métodos , Ácidos Docosa-Hexaenoicos/metabolismo , Óleos de Peixe/metabolismo , Lipase/metabolismo , Triglicerídeos/química , Triglicerídeos/síntese química , Atum/metabolismo , Animais , Candida/enzimologia , Ácidos Docosa-Hexaenoicos/química , Enzimas Imobilizadas/metabolismo , Esterificação , Glicerol/metabolismo , Hidrólise , Rhizomucor/enzimologia , Estereoisomerismo , Temperatura , Fatores de Tempo , Triglicerídeos/metabolismo
20.
N Biotechnol ; 26(1-2): 23-8, 2009 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-19481187

RESUMO

Candida antarctica lipase has generally been known to be nonregiospecific. This report, however, showed that its regiospecificity was linearly correlated to the index of polarity of the reaction mixture, which was calculated based on the dielectric constant of the components. Thus, it was strongly indicated that the regiospecificity depended on the polarity of the environment; the higher the polarity, the stricter the regiospecificity. The highest 1(3)-regiospecificity was obtained in the transesterification of oil with ethanol among other alcohols investigated. Although methanol, which is more polar than ethanol, was expected to give highest regiospecificity, it was fatal to the lipase. The transesterification of oil with ethanol (1:10, wt/wt) at 30 degrees C for three hours efficiently accumulated 2-monoacylglycerols without significant fatty acid (FA) specificity. Thus, it was successfully applied to regiospecifically analyze FA composition of triacylglycerols containing saturated and unsaturated FAs of C4-C24.


Assuntos
Lipase/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Esterificação/efeitos dos fármacos , Etanol/farmacologia , Ácidos Graxos/análise , Proteínas Fúngicas , Hexanos/farmacologia , Lipase/metabolismo , Estereoisomerismo , Especificidade por Substrato/efeitos dos fármacos , Triglicerídeos/química
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