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1.
M. A. M. Zeitoun W. E. Neff G. R. List T. L. Mounts 《Journal of the American Oil Chemists' Society》1993,70(5):467-471
Fat blends, formulated by mixing fully hydrogenated soybean oil with nine different commonly used vegetable oils in a ratio
of 1:1 (w/w), were subjected to interesterification (also commonly referred to as rearrangement or randomization) with sodium
methoxide catalyst. Fatty acid composition and triacylglycerol molecular species of each fat blend and the interesterified
product were determined and correlated with the following physical properties: melting, crystallization characteristics and
solid fat content. The differences in the endothermic and exothermic peak temperatures, total heat of fusion and crystallization
(β and β′ crystalline content) and solid fat content among the fat blends clearly showed the effect of the composition of
each oil on the physical properties. Oils that contained a considerable amount of palmitic acid had a favorable influence
on the crystallization and polymorphic form of interesterified fat blends. 相似文献
2.
G. R. List T. L. Mounts F. Orthoefer W. E. Neff 《Journal of the American Oil Chemists' Society》1995,72(3):379-382
Liquid vegetable oils (VO), including cottonseed, peanut, soybean, corn, and canola, were randomly interesterified with completely
hydrogenated soybean or cottonseed hardstocks (vegetable oil trisaturate; VOTS) in ratios of four parts VO and one part VOTS.
Analysis of the reaction products by high-performance liquid chromatography showed that at 70°C and vigorous agitation, with
0.5% sodium methoxide catalyst, the reactions were complete after 15 min. Solid-fat index (SFI) measurements made at 50, 70,
80, 92, and 104°F, along with drop melting points, indicated that the interesterified fats possess plasticity curves in the
range of commercial soft tub margarine oils prepared by blending hydrogenated stocks. Shortening basestocks were prepared
by randomly interesterifying palm or soybean oil with VOTS in ratios of 1:1 or 3:1 or 4:1, respectively. Blending of the interesterified
basestocks with additional liquid VO yielded products having SFI curves very similar to commercial all purpose-type shortening
oils made by blending hydrogenated stocks. Other studies show that fluid-type shortening oils can be prepared through blending
of interesterified basestocks with liquid VO. X-ray diffraction studies showed that the desirable β′ crystal structure is
achieved through interesterification and blending.
Presented at AOCS Annual Meeting & Expo, Atlanta, Georgia, May 8–12, 1994. 相似文献
3.
Silvia Hurtov Tefan Schmidt Jaroslav Zemanovi
Stanislav Sekretr Peter imon 《European Journal of Lipid Science and Technology》1996,98(2):60-65
Random interestification of fat blends, composed from vegetable oil and fully hydrogenated vegetable oil, catalyzed by sodium hydroxide and sodium methoxide, has been investigated. Sodium methoxide was used as a reference catalyst to evaluate the influence and the catalytic efficiency of NaOH on interesterification. Sodium hydroxide was found to be a suitable catalyst for this purpose. The choice of methods suitable for the investigation of interesterification reactions and characterization of the initial fat blends and their interesterified products is described. The randomization was followed by the changes in the triacylglycerol (TAG) composition of the fat blends determined by HPLC and high temperature GLC. This triacylglycerol composition of the original blends and the randomized products with the physical properties such as melting behaviour, crystallization and solid fat content were compared. The results show that the randomization of vegetable oil - fully hydrogenated vegetable oil fat blends in various ratios can be used to produce fats with desired physical and nutritional properties. 相似文献
4.
R. Ap. Ferrari W. Esteves K. D. Mukherjee 《Journal of the American Oil Chemists' Society》1997,74(2):93-96
Steryl ester content of refined and interesterified corn, soybean, and rapeseed oils has been measured via clean-up on a short silica gel column, followed by high performance liquid chromatography with evaporative light-scattering
mass detector. Chemical interesterification, catalyzed by sodium methoxide, led to random positional distribution of fatty
acids in triacylglycerols and some increase in the steryl ester content of all three oils. Enzymatic interesterification,
catalyzed by the immobilized lipase from Rhizomucor miehei (Lipozyme), resulted in a distinct reduction in steryl ester content, but essentially no alteration in positional distribution
of fatty acids in triacylglycerols occurred. Formation of steryl esters during chemical and enzymatic interesterification
was also examined by radioactive tracer technique with [4-14C]β-sitosterol added as marker to refined rapeseed oil and measurement of the radioactive steryl esters formed. Chemical interesterification
of rapeseed oil resulted in moderate formation (10% of total radioactivity) of radioactive β-sitosteryl esters. Enzymatic
interesterification of the oil, catalyzed by Lipozyme, led to little formation of radioactive β-sitosteryl esters, whereas
with the lipase from Candida cylindracea high proportions (>90% of total radioactivity) of 14C-labeled β-sitosteryl esters were formed.
Part of doctoral thesis of Roseli Ap. Ferrari to be submitted to Faculdade de Engenharia de Alimentos, Universidade de Campinas,
Campinas, Brazil. 相似文献
5.
Physical and chemical properties of trans-free fats produced by chemical interesterification of vegetable oil blends 总被引:1,自引:0,他引:1
V. Petrauskaite W. De Greyt M. Kellens A. Huyghebaert 《Journal of the American Oil Chemists' Society》1998,75(4):489-493
Fat blends, formulated by mixing a highly saturated fat (palm stearin or fully hydrogenated soybean oil) with a native vegetable
oil (soybean oil) in different ratios from 10:90 to 75:25 (wt%), were subjected to chemical interesterification reactions
on laboratory scale (0.2% sodium methoxide catalyst, time=90 min, temperature=90°C). Starting and interesterified blends were
investigated for triglyceride composition, solid fat content, free fatty acid content, and trans fatty acid (TFA) levels. Obtained values were compared to those of low- and high-trans commercial food fats. The interesterified blends with 30–50% of hard stock had plasticity curves in the range of commercial
shortenings and stick-type margarines, while interesterified blends with 20% hard stock were suitable for use in soft tubtype
margarines. Confectionery fat basestocks could be prepared from interesterified fat blends with 40% palm stearin or 25% fully
hydrogenated soybean oil. TFA levels of interesterified blends were low (0.1%) compared to 1.3–12.1% in commercial food fats.
Presented at the 88th AOCS Annual Meeting and Expo, May 11–14, 1997, Seattle, Washington. 相似文献
6.
G. R. List T. L. Mounts F. Orthoefer W. E. Neff 《Journal of the American Oil Chemists' Society》1997,74(3):327-329
Triglyceride structures of genetically modified soybean oils high in stearic acid were determined by high-pressure liquid
chromatography, and their physical properties were assessed by dilatometry and dropping point. In their natural state, these
oils lack sufficient solids at 10–33°C to qualify as margarine oils. However, after random interesterification, soybean oil
containing 17% stearic acid shows a solid fat index (SFI) profile and dropping point closely matching those of a liquid margarine
oil. Other oils, with stearic acid contents in the range of 20–33%, showed appreciable SFI values at 10°C but lacked sufficient
solids at 21.1–33.3°C. After random interesterification, these oils also exhibited SFI profiles suitable for soft tub margarine,
and their drop points increased from 18–19°C to 36–38°C. 相似文献
7.
M. M. Chakrabarty D. Bhattacharyya 《European Journal of Lipid Science and Technology》1972,74(7):389-393
Directed interesterification reaction in solvents of cottonseed, peanut and cottonseed containing peanut, sesame and safflower oils was investigated with special reference to the influence of amount of sodium methoxide catalyst, oil content in solvent, temperature during the reaction and the nature of solvent on the characteristics of the reaction. The parameters were first studied with cottonseed oil and the conditions that favoured the reaction were adopted for peanut oil and cottonseed oil mixtures. 相似文献
8.
The base-catalyzed transmethylation of soybean oil has been studied under conditions whereby the reaction starts as a single
phase, but later becomes two phases as glycerol separates. Methanol/oil molar ratios of 6∶1 were used at 23°C. The catalysts
were sodium hydroxide (0.5, 1.0, and 2.0 wt%), potassium hydroxide (1.0 and 1.4 wt%), and sodium methoxide (0.5, 1.0, and
1.35 wt%), all concentrations being with respect to the oil. Oxolane (tetrahydrofuran) was used to form a single reaction
phase. The reactions deviated from homogeneous kinetics as glycerol separated, taking with it most of the catalyst. When 1.0
wt% sodium hydroxide was used, the methyl ester content reached 97.5 wt% after 4 h, compared with 85–90 wt% in the two-phase
reaction. Sodium hydroxide (1.0 wt%), sodium methoxide (1.35 wt%), and potassium hydroxide (1.4 wt%) gave similar results,
presumably because the same number of moles was used. The ASTM biodiesel specification for chemically bound glycerol was achieved
after only 3 min when 2.0 wt% sodium hydroxide was used. However, the standard was not achieved after 4 h when 1.0 wt% sodium
hydroxide was used, the MG content being 1.1–1.6 wt%. The use of 2.0 wt% catalyst is commercially impractical. 相似文献
9.
Boleslaw Kowalski Katarzyna Tarnowska Eliza Gruczynska Witold Bekas 《European Journal of Lipid Science and Technology》2004,106(10):655-664
A mixture of beef tallow and rapeseed oil (1:1, wt/wt) was interesterified using sodium methoxide or immobilized lipases from Rhizomucor miehei (Lipozyme IM) and Candida antarctica (Novozym 435) as catalysts. Chemical interesterifications were carried out at 60 and 90 °C for 0.5 and 1.5 h using 0.4, 0.6 and 1.0 wt‐% CH3ONa. Enzymatic interesterifications were carried out at 60 °C for 8 h with Lipozyme IM or at 80 °C for 4 h with Novozym 435. The biocatalyst doses were kept constant (8 wt‐%), but the water content was varied from 2 to 10 wt‐%. The starting mixture and the interesterified products were separated by column chromatography into a pure triacylglycerol fraction and a nontriacylglycerol fraction, which contained free fatty acids, mono‐, and diacylglycerols. It was found that the concentration of free fatty acids and partial acylglycerols increased after interesterification. The slip melting points and solid fat contents of the triacylglycerol fractions isolated from interesterified fats were lower compared with the nonesterified blends. The sn‐2 and sn‐1,3 distribution of fatty acids in the TAG fractions before and after interesterification were determined. These distributions were random after chemical interesterification and near random when Novozym 435 was used. When Lipozyme IM was used, the fatty acid composition at the sn‐2 position remained practically unchanged, compared with the starting blend. The interesterified fats and isolated triacylglycerols had reduced oxidative stabilities, as assessed by Rancimat induction times. Addition of 0.02% BHA and BHT to the interesterified fats improved their stabilities. 相似文献
10.
Esters of carboxylic acids including 2-methylhexanoic, 2-methylbutyric, 2,2-dimethyl-4-pentenoic, palmitic, and oleic acids
were tested as substrates in methoxide-catalyzed interesterification and transesterification. The aliphatic acid esters participated
in the ester-ester interchange upon addition of catalytic sodium methoxide. Their isopropyl esters also produced methyl esters
on heating with sodium methoxide. The esters of α-methyl-substituted acids did not participate in the ester-ester interchange.
Their isopropyl esters did not react with methoxide to produce methyl esters. However, upon addition of methanol with sodium
methoxide, their methyl esters were produced. These results indicate that the first step in interesterification is possibly
that methoxide abstracts the α-hydrogen of an ester to form a carbanion. Interesterification is then likely completed via a Claisen condensation mechanism involving the β-keto ester anion as the active intermediate. The β-keto ester anion contains
positively charged ketone and acyl carbons that are active sites for nucleophilic attack by anions such as methoxide and glycerinate,
which would produce a methyl ester or rearrange acyls randomly. On the other hand, transesterification is a nucleophilic substitution
by methoxide at the acyl carbon in the presence of methanol. 相似文献
11.
Phosphorus in oil. Production of molybdenum blue derivative at ambient temperature using noncarcinogenic reagents 总被引:2,自引:0,他引:2
Enzo A. Tosi Ampelio F. Cazzoli Luis M. Tapiz 《Journal of the American Oil Chemists' Society》1998,75(1):41-44
The determination of phosphorus content in crude and degummed oils, especially soybean oil, is commonly used to monitor the
efficiency of the degumming process. Techniques for phosphorus determination are based on calcination of the oil in the presence
of zinc or magnesium oxide, followed by phosphomolybdate formation, a subsequent reduction and a spectrophotometric determination
of the final product, molybdenum blue. Several reducing agents have been employed, all of which need heating to develop color,
and then cooling before the absorbance is measured. The objective of this study was to investigate the use of potassium antimonyl
tartrate as a catalyst for the phosphomolybdate reduction with ascorbic acid at room temperature, to evaluate the useful life
of reagents, comparative kinetics of molybdenum blue formation (with and without catalyst addition) and the extent of phosphorus
recovery, and to compare these results with those from AOCS Official Method Ca 12–55. 相似文献
12.
J. Kurashige N. Matsuzaki H. Takahashi 《Journal of the American Oil Chemists' Society》1993,70(9):849-852
The bioreactor system to interesterify edible oils and fats at an ultra-micro aqueous phase of 100 ppm and less was investigated.
The adsorption of lecithin, together with lipase onto a carrier, was effective for conducting the interesterifying reaction
efficiently for oils and fats in micro aqueous phase.
To improve the handling properties of palm oil at rather low temperature, palm oil was blended with canola or soybean oil,
and then these blended oils were modified by enzymatic selective interesterification in a solvent-free, ultra-micro aqueous
bioreactor system with an immobilized lipase that had 1,3-positional specificity. The effects of enzymatic interesterification
were confirmed by triglyceride determination, by solid fat content profiles and by cloud point profiles, which were also compared
to products of chemical interesterification. The improvement in the fluidity of blended oils with canola oil by the enzymatic
reaction was bigger than with soybean oil, and chemical interesterification had no effects on the fluidity of blended oils. 相似文献
13.
R. O. Feuge L. P. Codifer H. J. Zeringue 《Journal of the American Oil Chemists' Society》1981,58(6):718-722
The titration of cyclopropenes in cottonseed and other oils with hydrogen bromide was improved by changes in the preparation
of the sample and the titration. Methanolysis of the oil under selected conditions with a large excess of alkaline catalyst
(sodium methoxide or tetramethylammonium hydroxide) yielded methyl esters free of oxidation products and partial glycerides
and eliminated the need for treatment with a large amount of activated alumina, which disproportionates methyl esters. The
color indicator, 4-phenylazodi-phenylamine, exhibited great sensitivity in toluene at 25 C. The best procedure consisted of
titrating methyl esters with hydrogen bromide at 60–65 C to just past the end-point, cooling to about 25 C, and back-titrating
with aniline in toluene. With 10- to 2-g samples containing less than 1% cyclopropenes, reproducibility usually was within
±0.003% of the average value. 相似文献
14.
G. R. List E. A. Emken W. F. Kwolek T. D. Simpson H. J. Dutton 《Journal of the American Oil Chemists' Society》1977,54(10):408-413
The sodium methoxide-catalyzed random interesterification of liquid soybean oil-soy trisaturate blends was explored as a possible
route to zerotrans margarine oils. Lipase hydrolysis of the rearranged fats showed that with 0.2% catalyst, interesterification is complete
within 30 min at 75-80 C. The glyceride structures of natural and randomized soybean oil-soy trisaturate blends are presented,
and relationships between their structure and physical properties are discussed. Organoleptic evaluations showed that randomization
of the glyceride structure had no adverse effects on flavor and oxidative stability. Flavor evaluations made against a commercially
hardened tub margarine oil showed that interesterified oil had comparable initial and aged flavor scores. X-ray diffraction
studies demonstrated that randomized soybean oil-soy trisaturate blends possess the beta-prime crystal structure desirable
for use in margarine production. Dilatometric data indicate that random interesterification of 20% by weight of soy trisaturate
into the glyceride structure of soybean oil provides a product having a solid fat index suitable for use in a soft tub margarine.
Presented at the AOCS Meeting, Chicago, September 1976. 相似文献
15.
Linshang Zhang Guolong Yang Jingnan Chen Yanlan Bi Shuai Chen Dandan Tan Jing Fu Dan Peng 《Journal of the American Oil Chemists' Society》2015,92(4):513-521
The effects of water content, acid value, and peroxide value on interesterification catalyzed by potassium glycerolate (in situ KOH/glycerol) were investigated using lard as a model fat. SEM analysis of KOH/glycerol powder showed that numerous 0.5‐ to 5‐μm porous structures were formed and may play an important role in the interesterification reaction. Water content (up to 10 %, oil weight) and peroxide value (4.29 and 7.11 mmol/kg) significantly extended the induction period of interesterification but complete randomization was still achievable. However, when the acid value reached 5.13 mg KOH/g, complete deactivation of the catalyst was observed at 1 % catalyst content (by oil weight). The sn‐2 fatty acid composition of fully randomized lard was similar to that of non‐randomized lard. Interesterification resulted in substantial rearrangement of the triacylglycerol species and alteration of thermal behaviors. The interesterified lard exhibited a predominant β′ polymorph, as opposed to the dominating β‐form crystals found in the original lard. 相似文献
16.
K. J. Moulton Sr. S. Koritala K. Warner 《Journal of the American Oil Chemists' Society》1985,62(12):1698-1701
Soybean oil was partially hydrogenated in a continuous system with copper and nickel catalysts. The hydrogenated products
were evaluated for flavor and oxidative stability. Processing conditions were varied to produce oils of linolenate contents
between 0.4 and 2.7%, as follows: oil flow, 0.6–2.2 liters/hr; reaction temperature, 180–220 C; hydrogen pressure, 100–525
psig, and catalyst concentration, 0.5–1% copper catalyst or 0.1% nickel catalyst.Trans unsaturation varied from 8 to 20% with copper catalyst and from 15.0 to 27% with nickel catalyst. Linolenate selectivity
was 9 with copper catalyst and 2 with nickel catalyst. Flavor evaluation of finished oils containing 0.01% citric acid (CA),
appraised initially and after accelerated storage at 60 C, showed no significant difference between hydrogenated oils and
nonhydrogenated oil. However, peroxide values and oxidative stability showed that hydrogenated oils were more stable than
the unhydrogenated oil. CA+TBHQ (tertiary butylhydroquinone) significantly improved the oxidative stability of test oils over
oils with CA only, but flavor scores showed no improvement. Dimethylpolysiloxane (MS) had no effect on either flavor or oxidative
stability of the oils. 相似文献
17.
Preparation of laurel oil alkanolamide from laurel oil 总被引:1,自引:1,他引:1
Hakan Kolancilar 《Journal of the American Oil Chemists' Society》2004,81(6):597-598
A low-temperature synthesis of laurel oil alkanolamides directly from laurel oil and ethanolamine was carried out in essentially
quantitative yields. The ethanolamine/laurel oil molar ratio used was 10∶1. Even though amine served as a catalyst in the
reaction, we used sodium methoxide at a ratio of 0.2–2% as a second catalyst. The reaction was complete in 1–9 h at room temperature.
The identity of the amide was confirmed by IR and 13C NMR spectroscopy. 相似文献
18.
Variables Affecting the Production of Standard Biodiesel 总被引:2,自引:0,他引:2
Sonam Mahajan Samir K. Konar David G. B. Boocock 《Journal of the American Oil Chemists' Society》2007,84(2):189-195
Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must
be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and
European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes
soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for
producing standard biodiesel from low-acid-number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent,
were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents
of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration,
cosolvent volume, and reaction time. The alcohol-to-oil molar ratio must be at least 14, and the sodium hydroxide concentration
should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume
of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of
the reactions. 相似文献
19.
M. A. Jackson J. W. King G. R. List W. E. Neff 《Journal of the American Oil Chemists' Society》1997,74(6):635-639
Enzymes can frequently impart more selectivity to a reaction than chemical catalysts. In addition, the use of enzymes can
reduce side reactions and simplify post-reaction separation problems. In combination with an environmentally benign and safe
medium, such as supercritical carbon dioxide (SC-CO2), enzymatic catalysis makes supercritical fluids extremely attractive to the food industry. In this study, randomization
of fats and oils was accomplished with an immobilized lipase in flowing SC-CO2. Triglycerides, adsorbed onto Celite, are solubilized in CO2 and carried over 1–10 g immobilized lipase derived from Candida antarctica. The degree of randomization and rate of triglyceride throughput could be controlled by CO2 pressure and flow rate and quantity of enzyme used. The dropping points and solid fat indices of the resulting randomized
oils were compared to oils that were randomized by conventional methods with sodium methoxide. Reversed-phase high-performance
chromatography with flame-ionization detection was used to quantitate changes in triglyceride composition of various substrates,
such as palm olein and high-stearate soybean oil. The resultant randomized oil mixtures have properties, e.g., solid fat index,
that make them potential candidates for incorporation into traditional margarine formulations. 相似文献
20.
Hiroaki Konishi William E. Neff Timothy L. Mounts 《Journal of the American Oil Chemists' Society》1993,70(4):411-415
Chemical interesterification reaction conditions that provide regioselectivity regarding fatty acid positions in triacylglycerol
have been investigated. Sodium methoxide-catalyzed ester interchange between soybean oil and methyl stearate was performed
in hexane at low reaction temperature,i.e., 30 to 60°C. The results showed regioselectivity was obtained at 30°C. The ester interchange at 1,3-carbons progressed 1.7
times faster than at 2-carbon of the glycerol moiety of triacylglycerol at 24 h. Preheating of the mixture of reactant and
catalyst at 60°C for 15 min promoted catalyst activation to accelerate the interesterification while maintaining regioselectivity.
This method is believed to be feasible for modification of edible fats and oils.
Presented at the American Oil Chemists’ Society’s Annual Meeting, May 10–14, 1992, Toronto, Canada. 相似文献