The bioconversions of oleic acid, linoleic acid, and ricinoleic acid by Pseudomonas aeruginosa PR3 were investigated. The conversion of oleic acid to 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was improved to better than 80% yields by modifying the culture medium and reaction parameters. The microbial cultures were stable and retained the same level of DOD production capacity for up to 6 mon as examined herewith. Strain PR3 did not bioconvert linoleic acid. However, strain PR3 converted ricinoleic acid to a novel compound, 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD), with a yield of about 35%. The product was further metabolized by strain PR3. TOD was purified by thin-layer chromatography, and its structure was determined by 1 H and 13 C nuclear magnetic resonance and mass spectrometry. This is the first report on the production of 7,10,12-trihydroxy unsaturated fatty acid by microbial transformation. JAOCS 75, 875-879 (1998).

The newly identified lipases of 67 bacterial strains, primarily Bacillus and Pseudomonas, from the ARS Culture Collection have been characterized on the basis of their positional specificity for triglycerides (triolein). Lipase was produced by growing the cultures in tryptone-glucose-yeast extract medium for 24 h at 30 degrees C before addition of triglyceride. The lipase was allowed to act on the triglyceride for 3 days before analysis by thin-layer chromatography. Of the bacterial lipases tested, 55 displayed random specificity, 9 were 1,3-specific, and 3 showed no apparent lipase activity under these conditions.

In the extraction of oils from seeds of the genus Coriandrum, GC separations of petroselinate from oleate often gave poor resolution of these two isomers. Oleic and petroselinic acids were esterified with a series of alcohols (methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 3-methyl-1-butanol, and 2-ethyl-1-hexanol). GC resolution of the ∆6 from the ∆9 and ∆11 octadecenoates was examined for all ester derivatives on a polar phase column. The ∆6 and ∆9 isomers were unresolved as methyl esters; however, the 2-ethyl-1-hexyl esters gave baseline separation of all three isomers under temperature programming conditions. When isothermal conditions were optimized for each ester, separation of these isomers was possible with good resolution values (>89%) for all the alcohols except methanol, which had a partial resolution of 51%. The rates of esterification of all the alcohols were determined for reactions with both oleic acid and triolein using potassium hydroxide as the esterification catalyst. Methanol gave the largest rate constant in both acid and oil esterification reactions with a rate constant 10-fold better than all of the other alcohols. Based on rates of reaction, resolution of petroselinate from oleate, and removal of residual alcohol, the ethyl ester derivative appears to be the best choice for seed oils containing petroselinic acid.Petroselinic acid is present in a number of seed oils but is most commonly found in the Umbelliferae family. One interest in this acid is that it could serve as a useful raw material for producing adipic and lauric acids via oxidative cleavage of the ∆6 double bond in petroselinic acid. Adipic acid is commonly used as a monomer for nylon synthesis, and lauric acid is used in detergent applications. Analysis of petroselinic acid in natural oils by GC is typically confounded by the presence of oleic acid. When methyl esters of petroselinic and oleic acids are synthesized, the GC separation of these two isomers is incomplete (1,2). Separation of petroselinate from oleate was reported to have only a 0.04 equivalent chain length (ECL) unit resolution, which made quantification of the individual isomers difficult.In an effort to overcome these quantification problems, several tedious chromatographic separation or derivatization techniques have been devised. Kleiman (3) used a combination of silver ion chromatography to isolate the monoene fraction of Umbelliflorae seed oils followed by ozonolysis and GC quantification of the cleavage products. Santinelli (4) epoxidized the olefins and then converted the epoxides to chlorohydrins via a hydrochloric acid-mediated ring opening. The resulting chlorohydrins were converted to their trimethylsilyl ethers, which were partially resolved by GC. Thies (5) treated the FA with dimethyldisulfide to make the bis-methylthio derivatives, which gave only partial separation by GC.Good separation of the ∆6 and ∆9 isomers has been reported using phenylethyl (6), isopropyl (7), and butyl (8-10) esters. The phenylethyl ester gives n...

A composição de ésteres metílicos de ácidos graxos (EMAGs) das variedades de café (Coffea arabica L.) Catuai, Catucaí, Bourbom, Mundo Novo, Rubí e Topázio conhecidas por produzirem bebidas de qualidade intermediária, ótima, ótima, intermediária, intermediária e inferior, respectivamente, foi determinada pela primeira vez. A (%) de área média dos seguintes ácidos das seis variedades foi: palmítico (38,2), esteárico (8,3), oléico (8,7), linoléico (38,5), linolênico (1,6) e araquidônico (3,6), respectivamente. O método é bastante rápido, com a completa caracterização das amostras estudadas (99%) ocorrendo em menos de 6 minutos. Enquanto esses valores podem fornecer informação para a avaliação da qualidade do café, nenhum efeito significativo (p < 0,05) da variedade de café foi encontrado na (%) de área das EMAGs. Além disso, foram comparados os EMAGs de: seis amostras de milho, seis marcas de café comerciais e uma amostra de café comercial intencionalmente adulterada com três quantidades de milho. Apesar da razão ácido linoléico/ácido esteárico encontrada nos EMAGs do café e do milho serem significativamente diferentes, não foi possível utilizar esse marcador para detectar adulteração do milho em cafés comerciais.Fatty acid methyl ester (FAME) composition of the coffee (Coffea arabica L.) varieties Catuai, Catucaí, Bourbom, Mundo Novo, Rubí and Topázio known to produce beverage of intermediate, excellent, excellent, intermediate, intermediate and poor quality, respectively, was determined for the first time. Average area % of the FAMEs of the six varieties was: palmitic (38.2), stearic (8.3), oleic (8.6), linoleic (38.5), linolenic (1.6) and arachidic (3.6) acids, respectively. The method was very quick with complete characterization (>99%) of the samples studied being possible in less than 6 min. While these values may provide insights for evaluating the coffee quality, no significant effect (p < 0.05) of coffee variety was found on area % of the FAMEs. In addition, FAMEs of six corn samples, six commercial coffee brands and one commercial coffee sample intentionally contaminated with three levels of corn were compared. Although the linoleic/stearic ratio was significantly different in coffee and corn FAMEs, this probe could not be used a marker to detect corn adulteration in commercial coffees.Keywords: coffee, coffee quality, fatty acids, corn, adulteration IntroductionCoffee (Coffea arabica, L.) quality may be lowered through hydrolysis of triacylglycerols (TAGs) resulting in release of free fatty acids (FAs) which are oxidized to produce off-flavor.1 However, no studies have been conducted relating FAs to coffee quality despite the fact that they are known to be important flavor components.2 Coffee quality can also be lowered by adulteration with cereals, coffee twigs, caramel, etc. This practice may be widespread in Brazil, with corn being considered the most widely used adulterant, due to its significantly lower cost. Few studies have been reported detecting corn in coffee 3-5 but only one study has detected...