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1.
Optimization of reaction conditions for the production of DAG using immobilized 1,3-regiospecific lipase lipozyme RM IM 总被引:9,自引:3,他引:9
Oils with a high DAG (1,3-DAG) content have attracted considerable attention as a healthful food oil component. In this study,
we report on the synthesis of 1,3-DAG from a mixture of FA, constituted largely of oleic and linoleic acids, using an immobilized
1,3-regioselective lipase from Rhizomucor miehei in a solvent-free system. The kinetics of 1,3-DAG production from FA and glycerol were investigated on the basis of a simplified
model, taking into consideration the acyl migration reaction, the removal of water, and glycerol dissolution in the oil phase
in addition to the esterification reactions. Both the yield of 1,3-DAG and the purity of DAG were evaluated under a variety
of experimental conditions, including reaction temperature, pressure, and amount of enzyme present. When either the reaction
temperature or the amount of enzyme used was increased, the 1,3-DAG production rate increased, but yield remained relatively
constant. The 1,3-DAG yield as well as the purity of DAG gradually decreased because of the enhancement of acyl migration
at later stages of the reaction after the 1,3-DAG concentration reached a maximum. Vacuum was important for attaining high
yields of 1,3-DAG. Under conditions of a high vacuum (1 mm Hg) at 50°C, 1.09 M 1,3-DAG was produced from 1.29 M glycerol and
2.59 MFA in an 84% yield and in 90% purity. 相似文献
2.
Synthesis of MAG of CLA with Penicillium camembertii lipase 总被引:1,自引:0,他引:1
Yomi Watanabe Yuji Shimada Yoshie Yamauchi-Sato Masaaki Kasai Takaya Yamamoto Kentaro Tsutsumi Yoshio Tominaga Akio Sugihara 《Journal of the American Oil Chemists' Society》2002,79(9):891-896
CLA has various physiological activities, and a FFA mixture containing almost equal amounts of cis-9,trans-11 and trans-10,cis-12 CLA (named FFA-CLA) has been commercialized. We attempted to produce MAG of CLA by a two-step successive reaction. The
first step was esterification of FFA-CLA with glycerol. A mixture of FFA-CLA/glycerol (1∶5, mol/mol), 2 wt% water, and 200
units/g of Penicillium camembertii mono-and diacylglycerol lipase was agitated at 30°C to form a homogeneous emulsion. The esterification degree reached 84%
after 10 h. To further increase the degree, the reaction was continued with dehydration at 5 mm Hg. The esterification degree
reached 95% after 24 h (34 h in total), and the reaction mixture contained 50 wt% MAG and 44 wt% DAG. The second step was
glycerolysis of the resulting DAG. The reaction mixture in the first-step esterification was transferred from the reactor
to a beaker and was solidified by vigorous agitation on ice. When the solidified mixture was allowed to stand at 5°C for 15
d, glycerolysis of DAG proceeded successfully, and MAG content in the reaction mixture increased to 88.6 wt%. Hydrolysis of
the acylglycerols was not observed during the second reaction. FA composition in the synthesized MAG was completely the same
as that in the original FFA-CLA, showing that Penicillium lipase does not have selectivity toward FA in the FFA-CLA preparation. 相似文献
3.
Da Xu Lijuan Sun Huayong Chen Dongming Lan Yonghua Wang Bo Yang 《Journal of the American Oil Chemists' Society》2012,89(7):1259-1266
Diacylglycerols (DAG) of conjugated linoleic acid (CLA) were prepared by esterification of glycerol with fatty acids enriched with CLA (FFA–CLA, >95%) in the presence of a novel lipase from Malassezia globosa (SMG1). Lipase SMG1 is strictly specific to mono- and diacylglycerols but not triacylglycerols, which is similar to the properties of lipase from Penicillium camembertii (lipase G 50), but lipase SMG1 showed preference on the production of DAG with the reaction proceeding. Low temperature was beneficial for the conversion of FFA–CLA into acylglycerols, the degree of esterification reached 93.0% when the temperature was 5 °C. The maximum DAG content (53.4%) was achieved at 25 °C. The rate of DAG synthesis increased as the enzyme loading increased. However, at lipase amounts above 240 U/g mixtures, no significant increases in DAG concentration were observed. The molar ratio of FFA–CLA to glycerol and initial water content were optimized to be 1:3 (mol/mol) and 3%. Lipase SMG1 showed no regioselectivity because the contents of 1,3-DAG and 1,2-DAG were 43.1% and 21.2% based on total content of acylglycerols. By calculating the ratio of 9c, 11t-CLA to 10t, 12c-CLA, it was indicated that lipase SMG1 showed a little preference to 10t, 12c-CLA at the sn-1(3) position of monoacylglycerols (MAG), while no selectivity for 9c, 11t-CLA at the sn-2 position of DAG was obviously found. 相似文献
4.
Yomi?Watanabe Yoshie?Yamauchi-Sato Toshihiro?Nagao Satoshi?Negishi Tadamasa?Terai Takashi?Kobayashi Yuji?Shimada
Production of MAG with CLA using Penicillium camembertii mono- and diacylglycerol lipase (referred to as lipase) was attempted for the purpose of expanding the application of CLA.
The commercial product of CLA (referred to as FFA-CLA) is a FFA mixture containing almost equal amounts of 9cis,11trans (9c,11t)-CLA and 10t,12c-CLA. Esterification of FFA-CLA with glycerol without dehydration achieved 84% esterification but produced almost equal amounts
of MAG and DAG. Esterification with dehydration not only achieved a high degree of esterification but also suppressed the
formation of DAG. When a mixture of FFA-CLA/glycerol (1∶2, mol/mol), 1% water, and 200 units/g-mixture of P. camembertii lipase was agitated at 30°C for 72 h with dehydration at 5 mm Hg, the degree of esterification reached 95% and the contents
of MAG and DAG were 90 and 6 wt%, respectively. This reaction system may be applied to the industrial production of MAG with
unstable CLA. 相似文献
5.
The aim of this paper was to develop a process for the production of DAG from butterfat through glycerolysis and short-path
distillation and to evaluate the physical properties of the DAG in comparison with the original butterfat. Chemical glycerolysis
produced a mixture of acylglycerols containing DAG together with MAG and TAG. From the mixture of glycerolysis products, MAG
were removed through three consecutive distillations (vacuum <0.001 mbar) at 150°C. TAG were separated from DAG by distillation
at 210°C, which gave a product with more than 80% DAG in the distillates. Distillation temperatures had significant effects
on acyl migration. The formation of desirable 1,3-DAG was favored at higher temperatures. Under 210°C distillation, the equilibrium
ratio of 6∶4 was obtained between 1,3-DAG and 1,2(2,3)-DAG. The FA profile of the DAG product was relatively similar to the
original butterfat. The total DAG recovery was around 77% in the pilot-scale production. The different patterns of m.p. were
observed between butterfat and the DAG fraction produced as well as the MAG fraction collected. Solid fat content profiles
of the DAG fraction and its mixtures with rapeseed oil possessed trends similar to those of the corresponding butterfat and
its mixtures with rapeseed oil. Compared with butterfat, the DAG fraction behaved differently in its thermal profiles, crystallization
patterns, and rheological properties; for example, the dropping point was 13°C higher for the latter than for the former,
and the crystal pattern was mostly β form for the latter, whereas the former was the β′ form. 相似文献
6.
The purification of tocopherols and phytosterols (referred to as sterols) from soybean oil deodorizer distillate (SODD) was
attempted. Tocopherols and sterols in the SODD were first recovered by short-path distillation, which was named sODD tocopherol/sterol
concentrate (SODDTSC). The SODD-TSC contained MAG, DAG, FFA, and unidentified hydrocarbons in addition to the two substances
of interest. It was then treated with Candida rugosa lipase to convert sterols to FA steryl esters, acylglycerols to FFA, and FFA to FAME. Methanol (MeOH), however, inhibited
esterification of the sterols. Hence, a two-step in situ reaction was conducted: SODDTSC was stirred with 20 wt% water and 200 U/g mixture of C. rugosa lipase at 30°C, and 2 moles of MeOH per mole of FFA was added to the reaction mixture after 16h. The lipase treatment for
40 h in total achieved 80% conversion of the initial sterols to FA steryl esters, complete hydrolysis of the acylglycerols,
and a 78% decrease in the initial FFA content by methyl esterification. Tocopherols did not change throughout the process.
To enhance the degree of steryl and methyl esterification, the reaction products, FA steryl esters and FAME, were removed
by short-path distillation, and the resulting fraction containing tocopherols, sterols, and FFA was treated with the lipase
again. Distillation of the reaction mixture purified tocopherols to 76.4% (recovery, 89.6%) and sterols to 97.2% as FA steryl
esters (recovery, 86.3%). 相似文献
7.
Fast Production of Diacylglycerol in a Solvent Free System via Lipase Catalyzed Esterification Using a Bubble Column Reactor
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Manman Liu Junning Fu Yinglai Teng Zhen Zhang Ning Zhang Yong Wang 《Journal of the American Oil Chemists' Society》2016,93(5):637-648
In this study, diacylglycerols (DAG) were synthesized rapidly (~30 min) in a solvent‐free system via esterification of glycerol with fatty acids (FA, the mixture of 60 wt% palm oil deodorizer distillate and 40 wt% oleic acid) catalyzed by Lipozyme 435 (Novozymes A/S, Copenhagen, Denmark) using a bubble column reactor. The content of DAG, monoacylglycerols (MAG), triacylglycerols (TAG) and free fatty acids (FFA) in the crude product were 57.94 ± 1.60 wt%, 24.68 ± 2.08 wt%, 2.67 ± 1.72 wt% and 14.69 ± 1.22 wt%, respectively under the selected conditions, which were enzyme load of 5.0 wt%, glycerol/FA mole ratio of 7.5, initial water content of 2.5 wt%, reaction temperature of 60 °C, reaction time of 30 min and N2 gas flow of 10.6 cm min?1. The final product containing 91.30 ± 1.10 wt% of DAG was obtained by one‐step molecular distillation at 200 °C. The reusability of Lipozyme 435 was investigated by evaluating the esterification degree (ED) and the DAG content in the crude products in 30 successive runs. The enzyme retained 95.10 % of its original activity during 30 successive runs according to comparison of the ED. The new process showed a very high efficiency in production of DAG with a high purity. The ratio of positional isomers 1,3‐DAG to 1,2 ‐DAG was 2:1 in the final product. The certain plasticity (melting point of 44 °C) and content of unsaturated fatty acids made the product a valuable food ingredient. 相似文献
8.
Low‐Temperature Chemical Synthesis of High‐Purity Diacylglycerols (DAG) from Monoacylglycerols (MAG)
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A chemical method was developed for low‐temperature synthesis of DAG from MAG followed by an easy purification procedure in order to obtain high‐purity DAG. Solvent‐assisted and solvent‐free reaction conditions were used, combined with different catalysts (sodium methoxide, p‐toluenesulfonic acid, methanesulfonic acid, and sulfuric acid). All reactions were performed at 35 and 70 °C. By increasing both acidity and polarity of the catalyst the equilibrium shifts towards the formation of DAG. When using sulfuric acid in solvent‐assisted condition at 70 °C, 88 % conversion was obtained after 20 min of reaction (77 % w/w DAG in the reaction mixture after evaporation of the solvent). After purifying by means of column chromatography, 96 % pure DAG were obtained. The overall yield of DAG was 81 %. 相似文献
9.
Preparation of Highly Pure n-3 PUFA-Enriched Triacylglycerols by Two-Step Enzymatic Reactions Combined with Molecular Distillation
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Daoming Li Weifei Wang Xuehui Li Rabia Durrani Bo Yang Yonghua Wang 《Journal of the American Oil Chemists' Society》2017,94(2):225-233
Highly pure n-3 polyunsaturated fatty acids (PUFA)-enriched triacylglycerols (TAG) have attracted considerable attention due to their nutritional benefits and pharmacological effects. In this study, an alternative approach to the conventional method for the synthesis of highly pure n-3 PUFA-enriched TAG by using a multi-step process was reported. First, glyceride mixtures were synthesized through Novozym 435 [Novozymes A/S (Bagsvaerd, Denmark)] catalyzed esterification of n-3 PUFA-enriched FA and glycerol. Second, partial glycerides in the resulting glyceride mixtures were hydrolyzed to FA by immobilized partial glycerides-selective lipase from Malassezia globosa. The purity of TAG reached 99.84% under the optimized conditions: buffer solution of pH 6.0, water content of 100% (w/w, with respect to the oil mass), enzyme loading of 120 U/g (U/w, with respect to oil mass) and reaction temperature of 30 °C. During hydrolysis, the immobilized SMG1-F278N exhibited good reusability and TAG purity of over 94% was maintained after being used for six cycles. Subsequently, purification of TAG was accomplished by molecular distillation at low temperature (150 °C) and highly pure (99.85%) TAG with 88.73% n-3 PUFA was obtained. The final glyceride mixtures with low acid, peroxide and anisidine value were promising products for medical and dietetic purposes. Compared with the conventional one-step synthesis of n-3 PUFA-enriched TAG by enzymatic esterification or glycerolysis or the two-step method by combined transesterification and ethanolysis, this improved process allows for higher purity of n-3 PUFA-enriched TAG and significant reduction in reaction time. 相似文献
10.
Zhong-Ming Wang Jin-Suk Lee Ji-Yeon Park Chuang-Zhi Wu Zhen-Hong Yuan 《Korean Journal of Chemical Engineering》2007,24(6):1027-1030
This paper describes an attractive method to make biodiesel from soybean soapstock (SS). A novel recovery technology of acid
oil (AO) from SS has been developed with only sulfuric acid solution under the ambient temperature (25±2 °C). After drying,
AO contained 50.0% FFA, 15.5% TAG, 6.9% DAG, 3.1% MAG, 0.8% water and other inert materials. The recovery yield of AO was
about 97% (w/w) based on the total fatty acids of the SS. The acid oil could be directly converted into biodiesel at 95 °C
in a pressurized reactor within 5 hours. Optimal esterification conditions were determined to be a weight ratio of 1 : 1.5
: 0.1 of AO/methanol/sulfuric acid. Higher reaction temperature helps to shorten the reaction time and requires less catalyst
and methanol. Ester content of the biodiesel derived from AO through one-step acid catalyzed reaction is around 92%. After
distillation, the purity of the biodiesel produced from AO is 97.6% which meets the Biodiesel Specification of Korea. The
yield of purified biodiesel was 94% (w/w) based on the total fatty acids of the soapstock. 相似文献
11.
Yomi?Watanabe Yoshie?Yamauchi-Sato Toshihiro?Nagao Takaya?Yamamoto Kentaro?Tsutsumi Akio?Sugihara Yuji?Shimada
We attempted to produce MAG of CLA through lipase-catalyzed esterification of a FFA mixture containing CLA (referred to as
FFA-CLA) with glycerol. Screening of lipases showed that MAG-CLA was produced efficiently at 5°C with Penicillium camembertii, Rhizopus oryzae, and Candida rugosa lipases. Among them, C. rugosa lipase was selected because the lipase is widely used as a catalyst for oils and fats processing. The reaction was conducted
with agitation of a 300-g mixture of FFA-CLA/glycerol (1∶5, mol/mol), a 200-U/g mixture of C. rugosa lipase, and 2% water. When the reaction was conducted at 30°C, the esterification scarcely proceeded, owing to inhibition
of the reaction by glycerol. But the reaction at 5°C eliminated the inhibition and produced MAG efficiently: The degree of
esterification reached 93.8% after 58 h, and MAG content in the reaction mixture was 88.4 wt%. To reduce the reaction time,
the reactor was connected with a vacuum pump after 24 h, and the reaction was continued with dehydration at 5 mm Hg. The degree
of esterification reached 94.7% after 24 h of dehydration (48 h in total), and MAG content increased to 93.0 wt%. Candida rugosa lipase acted a little more strongly on cis-9, trans-11 CLA than on trans-10,cis-12 CLA, but the contents of the two isomers in MAG obtained from a 48-h reaction were the same as the contents in FFA-CLA. 相似文献
12.
Production of MAG by a lipase-catalyzed reaction is known to be effective at low temperature. This phenomenon can be explained
by assuming that synthesized MAG are excluded from the reaction system because MAG, which have low m.p., are solidified at
low temperatures. Consequently, MAG are efficiently accumulated and do not serve as the precursor of DAG. If this hypothesis
is correct, the critical temperature for MAG production, defined as the highest temperature at which DAG synthesis is repressed,
should depend on the m.p. of the MAG. Esterification of FFA with glycerol using Candida rugosa, Rhizopus oryzae, and Penicillium camembertii lipases produced MAG efficiently at low temperatures. However, Candida lipase showed very low esterification activity at high temperatures (>20°C), and Rhizopus lipase produced not only MAG but also DAG even at low temperatures. Meanwhile, P. camembertii lipase catalyzed synthesis of MAG only from FFA and glycerol at low temperatures, although the enzyme catalyzed synthesis
of DAG from MAG in addition to synthesis of MAG at high temperatures. We thus studied the effect of temperature on esterification
of C10−C18 FFA with glycerol using Penicillium lipase as a catalyst and determined the critical temperatures for production of MAG. The critical temperature for production
of each MAG showed a linear correlation with m.p. of the MAG, which supported the hypothesis. In addition, because the m.p.
of MAG are estimated from that of the constituent FA, the optimal temperature for production of MAG can be predicted from
the m.p. of the FFA used as a substrate. 相似文献
13.
Leslie Kleiner Luis Vázquez Casimir C. Akoh 《Journal of the American Oil Chemists' Society》2012,89(11):1999-2010
Stearidonic acid (SDA, 18:4 ω-3) content of modified soybean oil (MSO) containing?~25?% SDA, was increased by lipase-catalyzed hydrolysis. Four non-immobilized powdered lipases, Lipase AY 30 (Candida rugosa), Lipase G 50 (Penicillium camembertii), Lipomod? 34P-L034P (Candida cylindracea [rugosa]), Lipomod? 36P-L036P (Rhizopus oryzae), and an immobilized lipase, Lipozyme RM IM (Rhizomucor miehei) were assessed, at various incubation times, for their ability to hydrolyze MSO and specificity toward SDA. The SDA enriched products contained triacylglycerols (TAG), diacylglycerols (DAG) and monoacylglycerols (MAG). Lipase 34P-L034P exhibited specificity towards SDA, while Lipase AY was able to discriminate against it. The highest total SDA content (40.9?mol%) was obtained with Amano AY lipase at 4?h incubation (66.2?% hydrolysis). Unhydrolyzed TAG, 1,3-DAG, 2,3(1)-DAG, and MAG contained 37.7 (56.4 at the sn-2 position), 41.6, 51.5 (54.9 at the sn-2 position), and 49.9?% SDA, respectively. Amano AY lipase was also used to hydrolyze previously SDA-enriched TAG (48.7?% SDA) obtained from low temperature crystallization of MSO. The highest total SDA content (62.7?mol%) was obtained at 12?h incubation (85.9?% hydrolysis). The SDA contents of unhydrolyzed TAG, 1,3-DAG, 2,3(1)-DAG, and MAG were 58.7 (65.7 at the sn-2 position), 71.2, 70.2 (52.9 at the sn-2 position), and 59.4?%, respectively. 相似文献
14.
Acid oil is a by-product in the neutralization step of vegetable oil refining and is an alternative source of biodiesel fuel.
A model substrate of acid oil, which is composed of TAG and FFA, was used in experiments on the conversion to FAME by immobilized
Candida antarctica lipase. FFA in the mixture of TAG/FFA were efficiently esterified with methanol (MeOH), but the water generated by the esterification
significantly inhibited methanolysis of TAG. We thus attempted to convert a mixture of TAG/FFA to FAME by a two-step process
comprising methyl esterification of FFA and methanolysis of TAG by immobilized C. antarctica lipase. The first reaction was conducted at 30°C in a mixture of TAG/FFA (1∶1, wt/wt) and 10 wt% MeOH using 0.5 wt% immobilized
lipase, resulting in efficient esterification of FFA. The reaction mixture after 24 h was composed of 49.1 wt% TAG, 1.3 wt%
FFA, 49.1 wt% FAME, and negligible amounts of DAG and MAG (<0.5 wt%). The reaction mixture was then dehydrated and used as
a substrate for the second reaction, which was conducted at 30°C in a solution of the dehydrated mixture and 5.5 wt% MeOH
using 6 wt% immobilized lipase. The activity of the lipase increased gradually when the reaction was repeated by transferring
the enzyme to a fresh substrate mixture. The activity reached a maximum after 6 cycles, and the content of FAME achieved was
>98.5 wt% after a 24-h reaction. The immobilized lipase was very stable in the first-and second-step reactions and could be
used for >100 d without significant loss of activity. 相似文献
15.
Yoshinori?Hirota Toshihiro?Nagao Yomi?Watanabe Masaharu?Suenaga Seiichi?Nakai Aktohiro?Kitano Akio?Sugihara Yuji?Shimada
Soybean oil deodorizer distillate (SODD) contains steryl esters in addition to tocopherols and sterols. Tocopherols and sterols
have been industrially purified from SODD but no purification process for steryl esters has been developed. SODD was efficiently
separated to low b.p. substances (including tocopherols and sterols) and high b.p. substances (including 11.2 wt% DAG, 32.1
wt% TAG, and 45.4 wt% steryl esters) by molecular distillation. The high b.p. fraction is referred to as soybean oil deodorizer
distillate steryl ester concentrate (SODDSEC). We attempted to purify steryl esters after a lipase-catalyzed hydrolysis of
acylglycerols in SODDSEC. Screening of industrially available lipases indicated that Candida rugosa lipase was most effective. Based on the study of several factors affecting hydrolysis, the reaction conditions were determined
as follows: ratio of SODDSEC/water, 1∶1 (w/w); lipase amount, 15 U/g reaction mixture; temperature, 30°C. When SODDSEC was
agitated for 24 h under these conditions, acylglycerols were almost completely hydrolyzed and the content of steryl esters
did not change. However, study with a mixture of steryl oleate/trilinolein (1∶1, w/w) indicated that about 20% of constituent
FA in steryl esters were exchanged with constituent FA in acylglycerols. Steryl esters in the oil layer obtained by the SODDSEC
treatment with lipase were successfully purified by molecular distillation (purity, 97.3%; recovery, 87.7%). 相似文献
16.
Akiko Kawashima Yuji Shimada Toshihiro Nagao Akihiro Ohara Tsugio Matsuhisa Akio Sugihara Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2002,79(9):871-877
γ-Linolenic acid (GLA) has the physiological functions of modulating immune and inflammatory responses. We produced structured
TAG rich in 1,3-dicapryloyl-2-γ-linolenoyl glycerol (CGC) from GLA-rich oil (GLA45 oil; GLA content, 45.4 wt%), which was
prepared by hydrolysis of borage oil with Candida rugosa lipase having weak activity on GLA. A mixture of GLA45 oil/caprylic acid (CA) (1∶2, w/w) was continuously fed into a fixed-bed
bioreactor (18×180 mm) packed with 15 g immobilized Rhizopus oryzae lipase at 30°C, and a flow rate of 4 g/h. The acidolysis proceeded efficiently, and a significant decrease of lipase activity
was not observed in full-time operation for 1 mon. GLA45 oil contained 10.2 mol% MAG and 27.2 mol% DAG. However, the reaction
converted the partial acylglycerols to structured TAG and tricaprylin and produced 44.5 mol% CGC based on the content of total
acylglycerols. Not only FFA in the reaction mixture but also part of the tricaprylin and partial acylglycerols were removed
by molecular distillation. The distillation resulted in an increase of the CGC content in the purified product to 52.6 mol%.
The results showed that CGC-rich structured TAG can efficiently be produced by a two-step process comprising selective hydrolysis
of borage oil using C. rugosa lipase (first step) and acidolysis of the resulting GLA-rich oil with CA using immobilized R. oryzae lipase (second step). 相似文献
17.
Enzymatic Production of Monoacylglycerols (MAG) and Diacylglycerols (DAG) from Fish Oil in a Solvent-Free System 总被引:2,自引:0,他引:2
Maria Manuela Camino Feltes Pierre Villeneuve Bruno Baréa Nathalie Barouh J. Vladimir de Oliveira Débora de Oliveira Jorge Luiz Ninow 《Journal of the American Oil Chemists' Society》2012,89(6):1057-1065
Mono- (MAG) and diacylglycerols (DAG) are of nutritional interest. MAG and DAG containing eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were produced in a solvent-free system via glycerolysis of menhaden oil catalyzed by Novozym 435. The effect of the molar ratio of glycerol to oil, enzyme concentration, and reaction temperature on MAG and DAG production was assessed. The optimal temperature was in the range of 55–70 °C for production of both acylglycerols. The increase in the substrates molar ratio led to a decrease in MAG and DAG content. The enzyme concentration was fixed at the lowest level evaluated (5%, by weight of substrates). High content of MAG (25% by weight) and DAG (41% by weight) containing, respectively, 12.46% EPA and 11.16% DHA, and 14.57% EPA and 13.70% DHA, were produced after 24 h at 70 °C, with 5% of lipase (by weight of substrate) and a glycerol-to-oil molar ratio of 1:1. For this reaction, a molar triacylglycerol (TAG) conversion of about 60% was achieved at equilibrium (10 h). 相似文献
18.
Estela Hernández-Martín Charles G. HillJr Cristina Otero 《Journal of the American Oil Chemists' Society》2009,86(5):427-435
Quasi-quantitative selective production of diacylglycerols (DAG) rich in polyunsaturated fatty acids (PUFA) was demonstrated
using a Penicillium camembertii lipase. Under optimal initial conditions [60 °C, 10% (w/w) biocatalyst based on total reactants, 5:1 molar ratio of free
conjugated linoleic acid (CLA) to hydroxyl groups in partial glycerides consisting of ca. 90% (w/w) monoacylglycerols (MAG)
and ca. 10% (w/w) diacylglycerols (DAG)], reaction for only 4.5 h gave 98.62% DAG and 1.38% MAG. The DAG contained >95% unsaturated
fatty acid residues. Predominant DAG were LnLn, LnL and LL, although LO and LP were also significant (Ln = linolenic; L = linoleic;
O = oleic; P = palmitic). Effects of the acylating agent (free CLA), solvent, and temperature on undesirable side reactions
were determined. Reaction selectivities were similar in n-hexane and solvent-free media. The re-esterified products contained less than 7% saturated fatty acids and a higher ratio
of unsaturated to saturated fatty acid residues (19.00) than the precursor soybean oil (5.22). The biocatalyst retained 55%
of its initial activity after use in three consecutive reaction/extraction cycles. 相似文献
19.
The present study investigated the metabolic fate of dietary TAG and DAG and also their digestion products in the stomach
and small intestine. A diet containing 10% TAG or DAG oil, enriched in 1,3-DAG, was fed to Wistar rats ad libitum for 9 d. After 18 h of fasting, each diet was re-fed ad libitum for 1 h. The weights of the contents of the stomach and small intestine were measured, and the acylglycerol and FFA levels
were analyzed by GC at 0, 1, and 4 h after the 1-h re-feeding. The amounts of re-fed diet ingested and the gastric and small
intestinal content were not different between the two diet groups. In the TAG diet group, the main products were TAG and DAG,
especially 1(3),2-DAG. In addition, 1,3-DAG and 1(3)-MAG were present in the stomach, and the 1,3-DAG levels increased over
time after the re-feeding period. In the DAG diet group, the main products in the stomach were DAG, MAG, FFA, and TAG. There
were significantly greater amounts of 1,3-DAG, 1(3)-MAG, and FFA in the DAG diet group in the stomach compared with the TAG
diet group. The amount of FFA in the stomach relative to the amount of ingested TAG plus DAG in the DAG diet group was higher
than that in the TAG diet group. Acylglycerol and FFA levels were considerably lower in the small intestine than in the stomach.
These results indicate that, in the stomach, where acyl migration might occur, the digestion products were already different
between TAG and DAG oil ingestion, and that DAG might be more readily digested by lingual lipase compared with TAG. Furthermore,
almost all of the dietary lipid was absorbed, irrespective of the structure of the acylglycerol present in the small intestine. 相似文献
20.
Jia Luo Zeping Wang Shangzhi Deng Fan Zhang Guirong Bao Junni Mao Wenjing Yang 《Journal of the American Oil Chemists' Society》2020,97(6):603-614
Direct glycerolysis of novel edible Sacha Inchi (Plukenetia volubilis L.) seed oil (PvLO) into diacylglycerols (DAG) and monoacylglycerols (MAG) was studied over solid Na2SiO3 with or without microwave assistance. The glycerolysis yield was calculated by qualitative and semiquantitative analyses of 1H NMR, 13C NMR, and FT-IR spectra. The yields of ~33% 1, 3-DAG, ~16% 1, 2-DAG, ~40% 1-MAG, and ~2.3% 2-MAG were achieved after 16 hours at 120 °C in three consecutive cycles using acetone, with an interesterification rate of 92%. The modified oil showed enhanced gelation ability at low temperatures. The yield of 1, 2-DAG can be increased by adding acetone as solvent. The fatty acid compositions and unsaturated structure of lipids were less destroyed after alkaline glycerolysis. However, more α-linolenic and linoleic acids were transferred to the sn-2 position of glyceryl skeleton. The oxidative stability of the modified oil was still controllable. In summary, this work provides a feasible method to convert polyunsaturated plant oils into oils rich in DAG and MAG with less destructive impact on the olefinic structure of oil. Also, it provides a useful example of how to quickly evaluate the influence of chemical modification on the chemical structure of plant oils by using various spectral technologies. 相似文献