bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of free fatty acids in palm oil by near‐infrared reflectance spectroscopy
Authors: Man Y. B. Che , Moh M. H.
Published: May 2007

A near‐infrared (NIR) spectroscopy calibration was developed for the determination of free fatty acids (FFA) in crude palm oil and its fractions based on the NIR reflectance approach. A range of FFA concentrations was prepared by hydrolyzing oil with 0.15% (w/w) lipase in an incubator at 60°C (200 rpm). Sample preparation was performed in Dutch cup, and the spectra were measured in duplicate for each sample. The optimized calibration models were constructed with multiple linear regression analysis based on C=O overtone regions from 1850–2050 nm. The best wavelength combinations were 1882, 2010, and 2040 nm. Multiple correlation coefficients squared (R2) were: 0.994 for crude palm oil, 0.961 for refined‐bleached‐deodorized (RBD) palm olein, and 0.971 for RBD palm oil. Calibrations were validated with an independent set of 8–10 samples. R2 of validation were 0.997, 0.943, and 0.945, respectively. The developed method was rapid, with a total analysis time of 5 min, and environmentally friendly, and its accuracy was generally good for raw‐material quality control.
A modified method for determining free fatty acids from small soybean oil sample sizes
Authors: Rukunudin I. H. , White P. J. , Bern C. J. , Bailey T. B.
Published: May 2007

A modification of the AOCS Official Method Ca 5a‐40 for determination of free fatty acids (FFA) in 0.3 to 6.0‐g samples of refined and crude soybean oil is described. The modified method uses only about 10% of the weight of oil sample, alcohol volume, and alkali strength recommended in the Official Method. Standard solutions of refined and crude soybean oil with FFA concentrations between 0.01 and 75% were prepared by adding known weights of oleic acid. The FFA concentrations, determined from small sample sizes with the modified method, were compared with FFA percentages determined from larger sample sizes with the Official Method. Relationships among determinations obtained by the modified and official methods, for both refined and crude oils, were described by linear functions. The relationship for refined soybean oil had an R2 value of 0.997 and a slope of 0.99±0.031. The values for crude soybean oil are defined by a line with R2=0.9996 and a slope of 1.01±0.013.
31P nuclear magnetic resonance phospholipid analysis of anionic‐enriched lecithins
Authors: Glonek Thomas
Published: May 2007

Phosphorus‐31 nuclear magnetic resonance provides well‐dispersed, quantifiable phospholipid profiles of commercial and laboratory anionic lecithin preparations. Seventeen phospholipids were determined in commercial soybean lecithins. Lecithin refinement to produce anionic‐enriched lecithins may be monitored precisely.
Assessment of quality changes in frozen sardine (Sardina pilchardus) by fluorescence detection
Authors: Aubourg Santiago P. , Sotelo Carmen G. , Pérez‐Martín Ricardo
Published: May 2007

The formation of fluorescent compounds was tested as a quality assessment during the frozen storage of sardine at −18°C (up to 24 mon) and at −10°C (up to 120 d). The fluorescence ratio between two excitation/emission maxima (393/463 and 327/415 nm) was studied in the aqueous (δFaq) and organic (δFor) extracts after Bligh and Dyer extraction of the white muscle. Fluorescence results were compared to common quality indices [total volatile base‐nitrogen (TVB‐N); conjugated dienes; thiobarbituric acid index (TBA‐i); and free fatty acids (FFA)]. δFaq showed good correlations with storage time (r=0.80 and r=0.72 at −18 and −10°C, respectively) and TBA‐i (r=0.92 and r=0.81). Principal‐component analysis grouped δFaq with quality indices that are sensitive for the assessment of fish damage during frozen storage at both temperatures (TBA‐i and FFA at −18°C; BVT‐N, TBA‐i, and FFA at −10°C). According to these results, fluorescence detection of interaction compounds in the aqueous phase can provide an accurate method to assess quality differences during frozen storage of fish.
Lipid oxidation in herring (Clupea harengus) light muscle, dark muscle, and skin, stored separately or as intact fillets
Authors: Undeland Irgrid , Ekstrand Bo , Lingnert Hans
Published: May 2007

Light muscle, dark muscle, and skin from herring (Clupea harengus) were stored separately or as intact fillets at −18°C. After 0, 2, 8, 12, and 18 wk, all tissues were analyzed for conjugated dienes (A234) and lipid hydroperoxides. In tissues stored separately, total absorbance at 268 nm (A268) and lipid‐soluble fluorescent oxidation products (FP) were also monitored. Further, prior to storage these tissues were subjected to measurement of total lipids, lipid classes, fatty acid pattern, α‐tocopherol, iron, copper, selenium, and total aqueous pro‐oxidative activity. When light muscle, dark muscle, and skin were stored as intact fillets, the following ranking order was seen for A234 and levels of lipid hydroperoxides at the end of the storage period: skin > dark muscle > light muscle. The corresponding ranking order for tissues stored separately was: dark muscle > skin > light muscle, whereas for A268 and FP the orders were: dark muscle > light muscle > skin and light muscle > dark muscle > skin, respectively. The compositional data obtained indicate the highest level of pro‐oxidants in dark muscle and the highest level of polar lipids in light muscle. These observations reveal that pro‐oxidants, to a greater extent than lipid composition, influence the increase in A234, hydroperoxides, and A268, whereas the reverse seems to be true for the increase in FP. The results also point to the strong influence from oxygen contact and tissue interactions on the progress of lipid oxidation in herring during storage.
Temperature effects on tocopherol composition in soybeans with genetically improved oil quality
Authors: Almonor G. O. , Fenner G. P. , Wilson R. F.
Published: May 2007

Tocopherol, a natural antioxidant, typically accounts for a small percentage of soybean (Glycine max L. Merr.) oil. Alleles that govern the expression of polyunsaturated fatty acids in soybean germplasm are influenced by temperature. However, little is known about the environmental influences on tocopherol expression. The objective of this study was to assess the influence of temperature on tocopherol composition in soybean germplasm that exhibit homozygous recessive and dominant alleles that govern the predominant ω‐6 and ω‐3 desaturases. The control cv. Dare and three low‐18:3 genotypes (N78‐2245, PI‐123440, N85‐2176) were grown under controlled‐temperature environments during reproductive growth. Analysis of crude oil composition at various stages of seed development revealed a strong negative correlation between total tocopherol content and growth temperature. The relative strength of this correlation was greater in the germplasm that exhibited homozygous alleles governing the ω‐6 desaturase than those governing the ω‐3 desaturase. The decline in total tocopherol with reduced temperature was attributed predominantly to loss of γ‐tocopherol. However, γ‐tocopherol concentration also was directly related to 18:3 concentration in all genotypes. Thus, low‐18:3 oils contained both a lower content and a lower concentration of γ‐tocopherol. Although the biochemical basis for this observation is unknown, the antioxidant capacity of γ‐tocopherol appeared to be directly associated with changes in oil quality that were mediated more by genetic than by environmental influences on 18:3 concentration. Another aspect of this work showed that low‐18:3 soybean varieties should be expected to contain more α‐tocopherol, especially when grown under normal commercial production environments. This condition should be regarded as another beneficial aspect of plant breeding approaches to the improvement of soybean oil quality.
Specific determination of malonaldehyde by N‐methyl‐2‐phenylindole or thiobarbituric acid
Authors: Inoue Tadamichi , Ando Ken , Kikugawa Kiyomi
Published: May 2007

Reactivity of a commercially available test kit (LPO‐586), based on N‐methyl‐2‐phenylindole, toward aldehydes was characterized and compared with that of thiobarbituric acid (TBA). In hydrochloric acid, LPO‐586 produced a violet pigment with malonaldehyde (MA) but not with other tested aldehydes. In methane sulfonic acid, LPO‐586 produced the violet pigment with MA and 4‐hydroxynonenal (HNE), but not with other tested aldehydes. Pigment formation with MA was not inhibited by other aldehydes, but that with HNE was inhibited by alka‐2,4‐dienals. TBA produced a red pigment with MA but not with other tested aldehydes in hydrochloric acid or in acetate with ethylenediaminetetraacetic acid (EDTA). Both the LPO‐586 test in hydrochloric acid and the TBA test in hydrochloric acid or in acetate with EDTA can be used for specific measurement of MA in oxidized lipid samples.
Selective oxidations of methyl ricinoleate: Diastereoselective epoxidation with titaniumIV catalysts
Authors: Foglia Thomas A. , Sonnet Philip E. , Nunez Alberto , Dudley Robert L.
Published: May 2007

Conditions were developed for the selective epoxidation of the double bond of methyl ricinoleate (1) with ethylmethyldioxirane (EMDO) to give the homoallylic epoxyalcohol, methyl (Z)‐9,10‐oxido‐12‐hydroxyoctadecanoate (2) in high yields but in poor enantiomeric excess. The diastereomeric ratio for epoxyalcohol 2 was improved modestly when t‐butyl‐hydroperoxide, coupled with a titanium catalyst and a d‐tartrate ligand, was used as oxidizing agent. Reaction of 1 with excess EMDO resulted in the concomitant epoxidation of the double bond and oxidation of the hydroxy group of 1 to give methyl (Z/it)‐9,10‐oxido‐12‐oxo‐octadecanoate (4), along with methyl 8‐(5‐hexylfuran‐2‐yl)octanoate (5). Alternatively, ketoepoxide 4 was prepared by dioxirane oxidation of methyl 12‐oxo‐(Z)‐9‐octadecene (3) or by treating epoxyalcohol 2 with sodium hypochlorite. The ketoepoxide 4 is acid‐labile and rearranges with loss of water to give furan 5 in high yield.
Structure and performance of soy hull carbon adsorbents as affected by pyrolysis temperature
Authors: Gnanasambandam Ravin , Mathias M. , Proctor A.
Published: May 2007

Soy hulls were evaluated as a source of adsorbent carbon for vegetable oil processing. Soy hull carbon was prepared by burning ground soy hulls (<100 mesh) at 300, 400, 500, or 700°C in a muffle furnace. The structure of the soy hull carbon was studied by scanning electron microscope (SEM), X‐ray diffraction (XRD), and Fourier‐transform infrared spectroscopy (FTIR). Crude soy oil was processed with the soy hull carbon products at 2% (w/w) in the laboratory under commercial bleaching conditions. Free fatty acids (FFA), peroxide value, phospholipid phosphorus (PLP), and lutein content of the treated samples were determined. SEM of the samples revealed particle size ranging from 1 to 2 mm. Increasing the pyrolysis temperature resulted in expansion and disruption of cellular structure. FTIR spectra of the carbon samples showed major differences in peak intensities at 3600 to 3200, 1600, and 1450 cm−1 due to pyrolysis temperature. XRD revealed a predominantly amorphous structure with increasing pyrolysis temperature, which also resulted in an increased alkaline surface. Soy hull carbon decreased the FFA content of oil samples compared to that of crude oil, with the exception of carbon that was prepared at 300°C (P<0.05). A similar trend was observed in the adsorption of peroxides; however, no trends were observed in the adsorption of PLP or lutein. Higher pyrolysis temperature decreased randomness of the carbon and imparted a certain degree of structural order. This may be beneficial in providing physical access of the adsorbate molecule to the adsorbent surface.
Kinetics of catalytic transfer hydrogenation of some vegetable oils
Authors: Naglič Mateja , Šmidovnik Andrej , Koloini Tine
Published: May 2007

Catalytic transfer hydrogenation of corn, peanut, olive, soybean, and sunflower oils has been studied with aqueous sodium formate solution as hydrogen donor and palladium on carbon as catalyst. Kinetic constants and selectivity have been determined under intensive stirring in the presence of stabilizing agents. Hydrogenation reactions followed first‐order kinetics with respect to fatty acids. Besides good selectivity and short reaction time, this method offers safe and easy handling. The presence of linolenic acid retards the migration of double bonds, which explains why soybean oil is the most appropriate for this hydrogenation process.
Inhibition of tubulin guanosine‐5′‐triphosphatase by lipid peroxides: Protective effects of vitamin A derivatives
Authors: Kawakami Misako , Ward Larry , Doi Hiroshi
Published: May 2007

Lipid peroxidation of cellular proteins has been postulated to be involved in cellular aging. Given the importance of the cytoskeleton in cellular function, it is a prime candidate as a potential target for the deleterious effects of lipid peroxides. In this study, the effects of lipid peroxides on microtubule assembly have been studied in an in vitro assay system, as have the protective effects of the vitamin A group (β‐carotene, retinal, and retinol). The assay was based on tubulin guanosine‐5′‐triphosphatase (GTPase) activity, which is associated with all steps of microtubule assembly. Soybean lecithin was utilized as the starting point to generate lipid peroxides. Its selection was based on the high proportion of phospholipids in the cellular membrane. Lipid peroxides were generated by photooxidation of lecithin, dissolved in methanol, in the presence of 0.004% methylene blue at 4°C for 8 h. Lipid peroxides (1.0 mg/mL) inhibited tubulin GTPase by 49%, relative to the control. Vitamin A derivatives (retinol, retinal, and β‐carotene) all had the ability to protect against the inhibitory effects of lipid peroxides, presumably owing to their antioxidant activities. This protective effect was more pronounced when utilizing a 30‐min, as opposed to a 15‐min, reaction time. This suggests a relatively slow rate of reaction between the peroxide and vitamin A group. These studies present a mechanism for the ability of vitamin A to inhibit aging of the cell.
Enzymatic glyceride synthesis in a foam reactor
Authors: Yeh Yu‐Chih , Gulari Erdogan
Published: May 2007

We report the results of our study on Rhizomucor miehei lipase‐catalyzed lauric acid‐glycerol esterification in a foam reactor. A satisfactory yield of glyceride synthesis can be achieved with an unusually high initial water content (50% w/w). We found that product formation could be regulated by controlling foaming. Foaming was a function of the air flow rate, reaction temperature, pH value, ionic strength, and substrate molar ratio. Monolaurin and dilaurin, which constituted nearly 80% of the total yield, were the two dominant products in this reaction; trilaurin was also formed at the initial stages of the reaction. A study of pH and ionic strength effects on an independent basis revealed that they affect the interfacial mechanism in different manners. On varying the ratio of lauric acid and glycerol, only a slight change in the degree of conversion was detected and the consumption rate of fatty acid was approximately the same.
Synthesis of monoterpene esters by alcoholysis reaction with Mucor miehei lipase in a solvent‐free system
Authors: Chatterjee T. , Bhattacharyya D. K.
Published: May 2007

The syntheses of geranyl acetate and citronellyl acetate by alcoholysis reaction catalyzed by immobilized lipase from Mucor miehei was studied for the first time in a solvent‐free system. Reactions were carried out at a terpene alcohol/acyl donor molar ratio of 1:5 with Lipozyme at 10% of the total weight of the reactants in a solvent‐free system. Incubations were carried out at 55 to 60°C for ethyl and butyl acetates as acyl donors, whereas for methyl acetate the incubation temperature was 40 to 45°C. Excess concentration of acyl donor increases the percentage of geranyl acetate and citronellyl acetate, while excess of terpene alcohol concentration decreases the same. Yields from 75 to 77% molar conversion (90 to 98% conversion, w/w) were obtained after 8 to 28 h of reaction time.
Reactions of olive oil and glycerol over immobilized lipases
Authors: Coteron A. , Martinez M. , Aracil J.
Published: May 2007

The reaction of olive oil and glycerol over immobilized lipases was studied. For oil samples with free fatty acid (FFA) contents larger than 2%, FFA esterification and glycerolysis took place simultaneously, but the esterification reaction was faster than glycerolysis. Similar product distributions were obtained for glycerol/oil mole ratios of 3:1 and 6:1. Therefore, an excess of glycerol does not result in a significant increase in monoglyceride yield within the experimental range tested. The main reaction product at 80°C was diglyceride. No increase in monoglyceride yield was observed by lowering the reaction temperature to 10°C.
Microbial synthesis of chiral intermediates for β‐3‐receptor agonists
Authors: Patel Ramesh N. , Banerjee Amit , Chu Linda , Brozozowski David , Nanduri Venkata , Szarka Laszlo J.
Published: May 2007

Chiral intermediates were prepared by biocatalytic processes for the chemical synthesis of β‐3‐receptor agonists. These include: (i) the microbial reduction of 4‐benzyloxy‐3‐methanesulfonylamino‐2′‐bromoacetophenone 1 to the corresponding (R)‐alcohol 2 by Spingomonas paucimobilis SC 16113. In the biotransformation process, a reaction yield of >85% and an optical purity of 99.5% were obtained for the desired (R)‐alcohol 2; (ii) the enzymatic resolution of racemic α‐methyl phenylalanine amide, 3, and α‐methyl‐4‐hydroxy‐phenylalanine amide, 5, by amidase from Mycobacterium neoaurum ATCC 25795 to prepare the corresponding (S)‐amino acids 4 and 6. Reaction yields of 49.9 and 49 M% (theoretical maximum yield 50 M%) and optical purities of 99 and 94% were obtained for the desired (S)‐amino acids 4 and 6, respectively; (iii) the asymmetric hydrolysis of methyl‐(4‐methoxyphenyl)‐propanedioic acid, ethyl diester, 7, to the corresponding (S)‐monoester 8 by pig liver esterase. A reaction yield of 96 M% and an optical purity of 96% were obtained for (S)‐monoester 8 when reactions were carried out in a biphasic system containing 10% ethanol at 10°C.
Production of polyhydroxy fatty acids from linoleic acid by Clavibacter sp. ALA2
Authors: Hou Ching T. , Gardner Harold , Brown Wanda
Published: May 2007

Hydroxy fatty acids are important industrial materials. We isolated a microbial culture, Clavibacter sp. ALA2, which converts linoleic acid to many polyhydroxy fatty acids. Structures of the products were determined as: 12,13,17‐trihydroxy‐9(Z)‐octadecenoic (THOA, main product), 12‐[5‐ethyl‐2‐tetrahydrofuranyl]‐7,12‐dihydroxy‐9(Z)‐dodecenoic (ETDDA), and 12‐[5‐ethyl‐2‐tetrahydrofuranyl]‐12‐hydroxy‐9(Z)‐dodecenoic (ETHDA) acid. The yield of THOA was 25% and the relative amount of the products were THOA/ETDDA/ETHDA =9:1.3:1. The structures of the hydroxy unsaturated fatty acids resemble those of plant self‐defense substances.
Application of potato lipid acyl hydrolase for the synthesis of monoacylglycerols
Authors: Macrae Alasdair R. , Visicchio Jean E. , Lanot Alexandra
Published: May 2007

Protein extracts from potato tubers contain a lipid acyl hydrolase (LAH) with an unusual selectivity. The component responsible for the enzyme activity is a group of closely related glycoproteins, known as patatin. Potato LAH catalyzes the rapid hydrolysis of monoacylglycerols (MAG), but in contrast expresses only low activity with di‐ and triacylglycerols. The selectivity of the LAH can be exploited for the synthesis of MAG from fatty acids and glycerol in microaqueous reaction systems. Oleic, linoleic, linolenic, capric, lauric, and myristic acids can be used as reactants, and in each case the reaction products contain >95 mol% MAG and <5 mol% diacylglycerol. By removing water from the reaction mixture by distillation under vacuum, excellent conversions of fatty acids into MAG are possible. Low conversions are observed with palmitic and stearic acids, because of the necessity to use a high temperature (70°C) to maintain a liquid reaction mixture. Potato LAH is rapidly inactivated at 70°C in the microaqueous reaction systems. Potato LAH also catalyzes the selective synthesis of monoesters from oleic acid and simple diols. With oleic acid and diglycerol, monoesters are again the main reaction products, but 17 mol% diesters are also formed.
Production of 8,11,14,17‐cis‐eicosatetraenoic acid (20:4ω‐3) by a Δ5 and Δ12 desaturase‐defective mutant of an arachidonic acid‐producing fungus Mortierella alpina 1S‐4
Authors: Kawashima Hiroshi , Sakuradani Eiji , Kamada Nozomu , Akimoto Kengo , Konishi Kyoko , Ogawa Jun , Shimizu Sakayu
Published: May 2007

A Δ5 and Δ12 desaturase‐defective mutant of an arachidonic acid‐producing fungus, Mortierella alpina 1S‐4, produced 8,11,14,17‐cis‐eicosatetraenoic acid (20:4ω3) intracellularly when grown with linseed oil. Dihomo‐γ‐linolenic acid was the only C20 polyunsaturated fatty acid (4.9 wt% of total mycelial fatty acids) other than 20:4ω3. AA and 5,8,11,14,17‐cis‐eicosapentaenoic acid were not detected. The mycelial lipids consisted of 82.2% (by mol) triacylglycerol (TG), 7.1% diacylglycerol, 8.9% phospholipids (PL), and 1.9% free fatty acids. The percentage of 20:4ω3 was higher in PL (30.1%) than in TG (11.6%), and highest in phosphatidylcholine (38.9%). Under the optimal conditions with a 5‐L jar fermenter, 20:4ω3 production amounted to 97.4 mg/g dry mycelia with a mycelial yield of 23 g/L on the twelfth day (corresponding to 2.24 g/L medium and 37.1% of total mycelial fatty acids).
Enhancement of arachidonic acid production by Mortierella alpina 1S‐4
Authors: Higashiyama Kenichi , Yaguchi Toshiaki , Akimoto Kengo , Fujikawa Shigeaki , Shimizu Sakayu
Published: May 2007

The effect of mineral addition on arachidonic acid (AA) production by Mortierella alpina 1S‐4 was evaluated. At first, the addition of minerals such as sodium, potassium, calcium, and magnesium was examined in flask cultures, and then the addition of phosphorus with the optimal amounts of the minerals was investigated in a 10‐L jar‐fermenter. As a result, 1.5% soy flour medium with the addition of 0.3% KH2PO4, 0.1% Na2SO4, 0.05% CaCl2·2H2O, and 0.05% MgCl2·6H2O was found to enhance the AA yield 1.7‐fold over that without mineral addition. When 1% yeast extract with the above mineral mixture was used, the AA yield was enhanced 1.35‐fold over that without minerals. We also verified that an increase in the polar lipid content occurred in the case of only KH2PO4 addition, and that the above‐mentioned increase in the AA yield was due to the minerals themselves, not a pH buffer effect.
Lipase‐catalyzed synthesis of kojic acid esters in organic solvents
Authors: Liu Kuan‐Ju , Shaw Jei‐Fu
Published: May 2007

Kojic acid is an inhibitor of bacteria, viruses, and fungi. It is used for inhibiting the browning effect of tyrosinase in the food and cosmetic industries. To improve its lipophilic properties, Pseudomonas cepacia lipase and Penicillium camembertii lipase were used for catalyzing the esterification of kojic acid to synthesize kojic acid monolaurate and kojic acid monooleate. These products showed a 69.5% inhibitory effect on tyrosinase in hydrophobic organic solvent. The yields of kojic acid esters were affected by enzymes, substrates, organic solvent, and temperature. Lauric and oleic acids were the best substrates for esterification among various fatty acids tested. CaCl2 and MnCl2 stimulate Pseudomonas cepacia lipasecatalyzed esterification by 7.0%. On the contrary, MgCl2, SrCl2, and ZnCl2 inhibited the reaction. The best pH of buffer for lipase pretreatment was pH 6.0. Pseudomonas and Penicillium lipases can be reused for the synthesis of kojic acid esters. After reaction at 40°C for 10 d, the Penicillium and Pseudomonas lipases still retained 57.0% and 92.0% of their initial activities, respectively.
Lipase‐catalyzed synthesis of chiral triglycerides
Authors: Chandler Ian C. , Quinlan Paul T. , McNeill Gerald P.
Published: May 2007

Under certain reaction conditions, the acidolysis of tripalmitin with oleic acid using immobilized lipase from Rhizomucor miehei resulted in a higher level of monosubstituted oleoyldipalmitoyl (OPP) triglycerides than had been predicted according to kinetic modeling. The reaction products were subjected to chiral analysis by high‐performance liquid chromatography (HPLC), which indicated that the enzyme was more active at the sn‐1 position of the triglyceride than at the sn‐3 position, resulting in synthesis of the chiral triglyceride 1‐oleoyl‐2,3‐dipalmitoyl‐sn‐glycerol. A kinetic model was developed and was correlated with the HPLC method to provide a simple means to predict the stereoselectivity of lipase‐catalyzed reactions. By using the model, the stereoselectivity of immobilized Rhizomucor miehei lipase was found to depend strongly on the initial water activity (aw) of the reaction mixture, with greater selectivity occurring at lower aw. The sn‐1 selectivity was essentially maintained using various solvents, or without solvent, when aw was kept constantly low. Variation in the fatty acid composition of the triglyceride indicated that shorter‐chain fatty acids result in greater stereoselectivity, while variation of the chainlength of the free fatty acid indicated an enhancement by the longest chainlength. The stereoselectivity of this lipase was confirmed using a new 13C nuclear magnetic resonance method. By using immobilized R. miehei lipase at low aw approximately 80% of the chiral triglyceride found in the reaction mixture was the sn‐1 enantiomer, at high reaction conversion.
Evaluation of immobilized modified lipase: Aqueous preparation and reaction studies in n‐hexane
Authors: Green Kenneth D. , Nakajima Mitsutoshi
Published: May 2007

Lipase Saiken 100 (Rhizopus japonicus) and its immobilized form displayed very poor activity (hydrolysis and interesterification) in microaqueous n‐hexane solutions. Enzyme modification by the addition of stearic acid or sorbitan monostearate significantly improved activity. A ceramic carrier (SM‐10) was used to immobilize modified lipase Saiken (stearic acid, sorbitan monostearate, and lecithin) and was found to further enhance hydrolysis and interesterification rates in n‐hexane. In addition, the biocatalysts were re‐used for four consecutive batch reactions with no significant shortfall in activity. Reaction rates were also greatly affected by the total reaction water content. Careful control of the biocatalyst water content prior to use and additional reaction water were required to optimize activity and minimize hydrolytic diglyceride byproducts. Hydrolysis and interesterification reaction rates were favored with immobilized biocatalyst water contents of 6.25 and 0.43 wt% with additional reaction water contents of 600 and 20 mg/L, respectively.
Optimization of the reaction conditions in the lipase‐catalyzed synthesis of structured triglycerides
Authors: Schmid U. , Bornscheuer U. T. , Soumanou M. M. , McNeill G. P. , Schmid R. D.
Published: May 2007

Structured triglycerides of the ABA‐type, containing one type of fatty acid (A) in the sn‐1 and sn‐3 positions and a second type of fatty acid (B) in the sn‐2 position of the glycerol, were synthesized using lipases. The highest yields and purities were achieved in a two‐step process, where a triglyceride of the B‐type was subjected to an alcoholysis reaction in an organic solvent catalyzed by sn‐1,3‐regiospecific lipases yielding the corresponding 2‐monoglyceride (2‐MG). Using this strategy, e.g., 2‐monopalmitin (2‐MP) was obtained in up to 88% yield at >95% purity by crystallization. Esterification of 2‐MP with oleic acid resulted in the formation of 1,3‐oleyl‐2‐palmitoyl‐glycerol in up to 72% yield containing 94% palmitic acid in the sn‐2 position. The best lipases were from Rhizomucor miehei, Rhizopus delemar, and Rhizopus javanicus. Water activity, solvent, and carrier for lipase immobilization strongly influenced the yield and purity of the products in both steps. Furthermore, 2‐MG from fish oil were produced by alcoholysis in up to 84% yield at >95% purity.
Solvent‐free enzymatic synthesis of structured lipids from peanut oil and caprylic acid in a stirred tank batch reactor
Authors: Lee Ki‐Teak , Akoh Casimir C.
Published: May 2007

Structured lipids were synthesized by transesterification of peanut oil and caprylic acid in a stirred‐batch reactor. Different substrate molar ratios (1:1 to 1:4, peanut oil/caprylic acid) were used. The reaction was performed for 72 h at 50°C catalyzed by IM60 lipase from Rhizomucor miehei (10 g, 2% w/w substrate) in the absence of organic solvent. The highest incorporation of caprylic acid was obtained with a 1:2 molar ratio (peanut oil/caprylic acid) after 72 h reaction. With a 1:2 molar ratio, the incorporation increased by 28% from 1:1. On the other hand, a 1:4 molar ratio gave the lowest incorporation during the reaction. The effect of different mixing speeds (200, 640, or 750 rpm) on reaction was studied with a 1:2 substrate molar ratio for 24 h. A high incorporation of caprylic acid (14.3 mol%) was obtained at 640 rpm, while 200 rpm gave the lowest incorporation (2.2 mol%), suggesting that good mixing is essential in a stirred‐batch reactor. After 24 h of reaction at different rpm, IM60 lipase was recovered, washed with hexane, and reacted with substrates to study its stability after reaction at different mixing speeds. The results showed that caprylic acid incorporation was similar (24.9, 24.3, 24.2 mol%) at 200, 640, and 750 rpm, respectively. When 20 g of IM60 lipase (4% w/w substrate) instead of 10 g was used in a 1:1 substrate molar ratio reaction, the incorporation of caprylic acid increased by 26% after 72 h. To study enzyme reuse, 10 g of IM60 lipase was used in a 1:1 substrate molar ratio for 24 h at 640 rpm. The incorporation of caprylic acid gradually decreased with increased number of reuses. During five times of reuse, 15, 13.9, 9.6, 6.7, and 9.7 mol% of caprylic acid were incorporated into peanut oil, respectively.
Large‐scale purification of γ‐linolenic acid by selective esterification using Rhizopus delemar lipase
Authors: Shimada Yuji , Sakai Norihito , Sugihara Akio , Fujita Hiroyuki , Honda Yo , Tominaga Yoshio
Published: May 2007

γ‐Linolenic acid (GLA) is a physiologically valuable fatty acid, and is desired as a medicine, but a useful method available for industrial purification has not been established. Thus, large‐scale purification was attempted by a combination of enzymatic reactions and distillation. An oil containing 45% GLA (GLA45 oil) produced by selective hydrolysis of borage oil was used as a starting material. GLA45 oil was hydrolyzed at 35°C in a mixture containing 33% water and 250 U/g‐reaction mixture of Pseudomonas sp. lipase; 91.5% hydrolysis was attained after 24 h. Film distillation of the dehydrated reaction mixture separated free fatty acids (FFA; acid value 199) with a recovery of 94.5%. The FFA were selectively esterified at 30°C for 16 h with two molar equivalents of lauryl alcohol and 50 U/g of Rhizopus delemar lipase in a mixture containing 20% water. The esterification extent was 52%, and the GLA content in the FFA fraction was raised to 89.5%. FFA and lauryl esters were not separated by film distillation, but the FFA‐rich fraction contaminated with 18% lauryl esters was recovered by simple distillation. To further increase the GLA content, the FFA‐rich fraction was selectively esterified again under similar conditions. As a result, the GLA content in the FFA fraction was raised to 97.3% at 15.2% esterification. After simple distillation of the reaction mixture, lauryl esters contaminating the FFA‐rich fraction were completely eliminated by urea adduct fractionation. When 10 kg of GLA45 oil was used as a starting material, 2.07 kg of FFA with 98.6% GLA was obtained with a recovery of 49.4% of the initial content.
Separation of eicosapentaenoic acid and docosahexaenoic acid in fish oil by kinetic resolution using lipase
Authors: Haraldsson Gudmundur G. , Kristinsson Björn
Published: May 2007

The objective of this study was to investigate the use of lipases as catalysts for separating eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil by kinetic resolution. Transesterification of various fish oil triglycerides with a stoichiometric amount of ethanol by immobilized Rhizomucor miehei lipase under anhydrous solvent‐free conditions resulted in a good separation. When free fatty acids from the various fish oils were directly esterified with ethanol under similar conditions, greatly improved results were obtained. By this modification, complications related to regioselectivity of the lipase and nonhomogeneous distribution of EPA and DHA into the various positions of the triglycerides were avoided. As an example, when tuna oil comprising 6% EPA and 23% DHA was transesterified with ethanol, 65% conversion into ethyl esters was obtained after 24 h. The residual glyceride mixture contained 49% DHA and 6% EPA (8:1), with 90% DHA recovery into the glyceride mixture and 60% EPA recovery into the ethyl ester product. When the corresponding tuna oil free fatty acids were directly esterified with ethanol, 68% conversion was obtained after only 8h. The residual free fatty acids comprised 74% DHA and only 3% EPA (25:1). The recovery of both DHA into the residual free fatty acid fraction and EPA into the ethyl ester product remained very high, 83 and 87%, respectively.
Transesterification of trimethylolpropane and rapeseed oil methyl ester to environmentally acceptable lubricants
Authors: Uosukainen Esa , Linko Yu‐Yen , Lämsä Merja , Tervakangas Tommi , Linko Pekka
Published: May 2007

Biodegradable trimethylolpropane [2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol] esters of rapeseed oil fatty acids were synthesized by transesterification with rapeseed oil methyl ester both by enzymatic and chemical means, both in bench and pilot scales. Nearly complete conversions were obtained with both techniques. A reduced pressure of about 2 to 5 kPa, to remove the methanol formed during transesterification, was critical for a high product yield. The quantity of added water was also critical in the biocatalysis. Candida rugosa lipase was used as biocatalyst and an alkaline catalyst in chemical transesterifications. In biocatalysis the maximum total conversion to trimethylolpropane esters of up to 98% was obtained at 42°C, 5.3 kPa, and 15% added water. The maximum conversion of about 70% to the tri‐ester was obtained at the slightly higher temperature of 47°C. The reaction time was longer in the biocatalysis, but considerably higher temperatures were required in chemical synthesis. In the chemical synthesis tri‐ester yields increased when the temperature was first held at 85 to 110°C for 2.5 h and subsequently increased to up to 120°C for 8 h. The trimethylolpropane esters obtained were tested as biodegradable hydraulic fluids and compared to commercially available hydraulic oils. The hydraulic fluids based on trimethylolpropane esters of rapeseed oil had good cold stability, friction and wear characteristics, and resistance against oxidation at elevated temperatures.
Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase
Authors: Shimada Yuji , Maruyama Kazuaki , Sugihara Akio , Baba Takashi , Komemushi Sadao , Moriyama Shigeru , Tominaga Yoshio
Published: May 2007

Ethyl docosahexaenoate (E‐DHA) is efficiently enriched by the selective alcoholysis of ethyl esters originating from tuna oil with lauryl alcohol using immobilized lipase. Alcoholysis of ethyl esters by immobilized Rhizopus delemar lipase raised the E‐DHA content in the unreacted ethyl ester fraction from 23 to 49 mol% in 90% yield. However, the content of ethyl eicosapentaenoate (E‐EPA) was higher than the initial content. Hence we attempted to screen for a suitable lipase to decrease the E‐EPA content, and chose Rhizomucor miehei lipase. Several factors affecting the alcoholysis of ethyl esters were investigated, and the reaction conditions were determined. When alcoholysis was performed at 30°C with shaking in a mixture containing ethyl esters/lauryl alcohol (1:3, mol/mol) and 4 wt% of the immobilized R. miehei lipase, the E‐DHA content in the ethyl ester fraction was increased and the E‐EPA content was decreased. By alcoholyzing ethyl esters in which the E‐DHA content was 45 mol% (E‐tuna‐45) for 26 h, the E‐DHA content was increased to 74 mol% in 71% yield and the E‐EPA content was decreased from 12 to 6.2 mol%. To investigate the stability of the immobilized lipase, batch reactions were carried out continually by replacing the reaction mixture with fresh E‐tuna‐45/lauryl alcohol (1:3, mol/mol) every 24 h. The decrease in the alcoholysis extent was only 17% even after 100 cycles of reaction. It was found that increasing the proportion of lauryl alcohol increased the conversion of E‐EPA to lauryl‐EPA. When an ethyl ester mixture in which the E‐DHA content was 60 mol% (E‐tuna‐60) was alcoholyzed for 24 h with 7 molar equivalents of lauryl alcohol, the E‐DHA content was raised to 93 mol% with 74% yield and the E‐EPA content was reduced from 8.6 to 2.9 mol%.
Selective hydrolysis of borage oil with Candida rugosa lipase: Two factors affecting the reaction
Authors: Shimada Yuji , Fukushima Nobuhiro , Fujita Hiroyuki , Honda Yo , Sugihara Akio , Tominaga Yoshio
Published: May 2007

A 46% γ‐linolenic acid (GLA)‐containing oil was produced by selective hydrolysis of borage oil (GLA content, 22%) at 35°C for 15 h in a mixture containing 50% water and 20 units (U)/g reaction mixture of Candida rugosa lipase. The GLA content was not raised over 46%, even though the hydrolysis extent was increased by extending the reaction time and by using a larger amount of the lipase. However, 49% GLA‐containing oil was produced by hydrolysis in a reaction mixture with 90% water. This result suggested that free fatty acids (FFA) that accumulated in the mixture affected the apparent fatty acid specificity of the lipase in the selective hydrolysis and interfered with the increase of the GLA content. To investigate the kinetics of the selective hydrolysis in a mixture without FFA, glycerides containing 22, 35, and 46% GLA were hydrolyzed with Candida lipase. The result showed that the hydrolysis rate decreased with increasing GLA content of glycerides, but that the release rate of GLA did not change. Thus, it was found that the apparent fatty acid specificity of the lipase in the selective hydrolysis was also affected by glyceride structure. When 46% GLA‐containing oil was hydrolyzed at 35°C for 15 h in a mixture containing 50% water and 20 U/g of the lipase, GLA content in glycerides was raised to 54% at 20% hydrolysis. Furthermore, GLA content in glycerides was raised to 59% when the hydrolysis extent reached 60% using 200 U/g of the lipase. These results showed that repeated hydrolysis was effective to produce the higher concentration of GLA oil. Because film distillation was found to be extremely effective for separating FFA and glycerides, large‐scale hydrolysis of borage oil was attempted. As a result, 1.5 kg of 56% GLA‐containing oil was obtained from 7 kg borage oil by repeated reaction.
Trans fatty acids in Canadian margarines: Recent trends
Authors: Ratnayake W. M. N. , Pelletier G. , Hollywood R. , Bacler S. , Leyte D.
Published: May 2007

The fatty acid composition and the trans fatty acid content of the top‐selling 109 Canadian margarines were determined by a combined capillary gas‐liquid chromatography/infrared spectroscopy method. The 109 brands accounted for 68% of the margarine brands sold in Canada and represented 74% of the market share. The mean level of total trans content in tub margarines (n=79) was 18.8% (g/100 g fatty acids) and ranged from 0.9 to 46.4%. The most frequent occurrence of trans in tub margarines was in the 15–20% range; 48 of the 79 tub brands were in this range but seven brands contained more than 40% trans. The trans content of hard margarines (n=30) ranged from 16.3 to 43.7% and the mean value was 34.3%. In 20 of the 109 brands, the levels of trans,trans isomers of linoleic acid exceeded the maximum level of 1% recommended for Canadian margarines. The levels of cis,trans/trans,cis isomers of linoleic acid were also high; 78 brands contained more than 1% and in 16 brands, the levels were in the 6–7% range. Linoleic acid content in the 109 brands ranged from 1.0 to 45.2% and averaged 18.3%. In 33 samples, linoleic acid was below the level of 5% recommended by an ad hoc committee of Health Canada. Moreover, in these, the total trans content exceeded 30%, and trans polyunsaturated fatty acid level was greater than 5%. There were eight margarines prepared from nonhydrogenated fat and their total trans content was below 2.5%. From the trans content and market share of each of the margarine brands, the average intake of trans fatty acids from margarine was estimated as 0.96 g/person/d. The intake of trans fatty acids in Canada from various sources was previously estimated by us as 8.4 g/person/d. Thus it is suggested that only 11% of the dietary trans fatty acids are supplied by margarines and the majority of trans fatty acids in the Canadian diet is derived from hidden fats in fast foods and bakery products.
Antioxidant and radical‐scavenging activities of buckwheat seed components
Authors: Przybylski R. , Lee Y. C. , Eskin N. A. M.
Published: May 2007

The search for endogenous components in food ingredients exhibiting antioxidant activity has been intensified in order to eliminate synthetic antioxidants. Tocopherols are widely used as natural antioxidants, although their protective ability is not always sufficient. Buckwheat seed components were evaluated for antioxidant and free radical‐scavenging activities using solvents of different polarities to isolate components from hulls and groats. Components extracted from buckwheat hulls were pro‐oxidant in canola oil. Antioxidant activity of extracts from buckwheat groats increased when more polar solvents were used for extraction. The highest activity was observed for the methanolic extract. Radical‐scavenging activity of buckwheat extracts was analyzed with DPPH (2,2‐diphenyl‐2‐picryl‐hydrazyl). This activity increased when the more polar solvents were used for extraction, with the highest activity observed for the methanolic extract. It was also observed that the radical scavenging effectiveness of extracts was concentration dependent. Analysis revealed the presence of tocopherols in the hexane extract, while methanolic extracts were rich in phenolic acids and flavonoids.
Relation of fat bloom in chocolate to polymorphic transition of cocoa butter
Authors: Bricknell J. , Hartel R. W.
Published: May 2007

A special chocolate with spray‐dried sugar (50:50 w/w sucrose/20 Dextrose Equivalent corn syrup solids) was made to study the polymorphic changes in cocoa butter crystals using X‐ray diffraction. Anhydrous milk fat (AMF) and high‐, middle‐, and low‐melting milk fat fractions were used to replace 2% (w/w) of cocoa butter. Chocolates were tempered, and the consistency of temper among chocolate samples was verified by a temper meter. Chocolates were cycled between 19 and 29°C at 6‐h intervals to induce fat bloom. The special chocolates were analyzed by X‐ray spectroscopy and colormeter.

X‐ray analysis on the special chocolates showed polymorphic transition from the βV to the βVI form of cocoa butter. After a lag phase, the percentage of the βVI form rapidly increased. However, the sample made with the high‐melting milk fat fraction transformed slowly to βVI. Visual bloom appeared rapidly on the special chocolates made with AMF, middle‐ and low‐melting fractions, whereas visual bloom was very slow to appear on the special chocolates made with high‐melting milk fat fraction and on the cocoa butter control. The commercial chocolate responded consistently; the control bloomed rapidly, the AMF exhibited some bloom resistance, and the high‐melting fraction inhibited bloom. Despite the βV to βVI transition, the control chocolates with amorphous sugar did not bloom. Since the only difference in the chocolates was sugar microstructure, differences in bloom formation were caused by the microstructure, not the polymorphic transition.
Thermal analysis of isothermal crystallization kinetics in blends of cocoa butter with milk fat or milk fat fractions
Authors: Metin Serpil , Hartel Richard W.
Published: May 2007

The kinetics of isothermal crystallization of binary mixtures of cocoa butter with milk fat and milk fat fractions were evaluated by applying the Avrami equation. Application of the Avrami equation to isothermal crystallization of the fats and the binary fat blends revealed different nucleation and growth mechanisms for the fats, based on the Avrami exponent. The suggested mechanism for cocoa butter crystallization was heterogeneous nucleation and spherulitic growth from sporadic nuclei. For milk fat, the mechanism was instantaneous heterogeneous nucleation followed by spherulitic growth. For milk fat fractions, the mechanism was high nucleation rate at the beginning of crystallization, which decreased with time, and plate‐like growth. Addition of milk fat fractions did not cause a significant change in the suggested nucleation and growth mechanism of cocoa butter.
Physico‐chemical characteristics of palm‐based oil blends for the production of reduced fat spreads
Authors: Lida Habi Mat Dian Noor , Ali A. Rahim Md
Published: May 2007

The effect of blending and interesterification on the physicochemical characteristics of fat blends containing palm oil products was studied. The characteristics of the palm‐based blends were tailored to resemble oil blends extracted from commercial reduced fat spreads (RFS). The commercial products were found to contain up to 20.4% trans fatty acids, whereas the palm‐based blends were free of trans fatty acids. Slip melting point of the blends varied from 26.0–32.0°C for tub, and 30.0–33.0°C for block RFS. Solid fat content at 5 and 10°C (refrigeration temperature), respectively, varied from 10.9–19.7% and 8.5–17.6% for tub, and 28.2–38.6% and 20.8–33.5% for block RFS. Melting enthalpy of the tub RFS varied from 35.0–54.3 J/g and that of block RFS varied from 58.0–75.4 J/g. To produce block RFS, 65% palm oil (PO) and 18% palm kernel olein (PKOo) could be added in a ternary blend with sunflower oil (SFO), but only 47% PO and 10% PKOo are suggested for tub RFS. Higher proportion of PO, i.e., 72% for block RFS and 65% for tub RFS, could be used after the ternary blend was interesterified. Although a ternary blend of palm olein (POo)/SFO/PKOo was not suitable for RFS formulation, after interesterification as much as 90% POo and 26% PKOo could be used in the block RFS formulation. For tub RFS a maximum of 30% POo was found suitable.