Sara P. Fore

Direct gas chromatographic examination of volatiles in salad oils and shortenings

A simple, rapid and direct gas chromatographic technique was developed for the examination of volatiles in salad oils and shortenings at the 10 ppb level without prior enrichment. The liner of the inlet of the gas chromatograph is carefully packed with volatile-free glass wool to allow slow diffusion of the sample on the glass wool, but to prevent seepage onto the gas chromatographic column. The liner with sample is inserted in the heated inlet, and the volatiles are eluted rapidly from the samples as the carrier gas flows through the linear and sweeps the volatiles onto the column, which is temperature-programed between 55 and 190C to resolve the volatiles. Numerous samples of salad oils and shortenings were examined, and the better quality oils had only small amounts of volatiles.

Factors affecting the stability of crude oils of 16 varieties of peanuts

SummaryThe relation between fatty acid compositions, tocopherol contents, and autoxidative stabilities of a series of 16 crude oils from different varieties of peanuts has been investigated. It was found that the relative linoleic acid content of the oils is one of the major factors affecting the variations in the stabilities of the oils tested. With the exception of the oils from Runner peanuts the tocopherol compositions of the oils were not found to vary significantly, either in the nature and distribution of individual tocopherols, or in total tocopherol contents. The enhanced stability of the oils from the Runner peanuts may be due in part to the higher tocopherol contents of these oils. There is some evidence that crude peanut oils contain some non-tocopherol antioxidant and/or synergist.

DETERMINATION OF RESIDUAL SOLVENT IN OILSEED MEALS AND FLOURS BY A VOLATILIZATION PROCEDURE

A simple volatilization procedure was developed for the determination of residual hexane in oilseed meals and flours. A 2 g sample of meal or flour and 0.2 g of water are weighed into a 120 ml serum bottle, which is sealed and heated at 110 C for 2 hr in an oven. A 1 ml aliquot of the head-space gas is then analyzed by gas chromatography. The concentration of residual hexane is easily determined by comparing the area of the appropriate peak of the chromatogram with a calibration chart. Results are reproducible within ±20%, and concentrations as low as 1 ppm can be detected. The technique is much simpler and more efficient than other procedures available. It also appears to be useful for determining other residual solvents such as acetone and isopropanol, and acetone impurities such as mesityl oxide and diacetone alcohol in oilseed meals and flours.

Elution and analysis of volatiles in vegetable oils by gas chromatography

A simple and very sensitive technique was devised to analyze volatiles in vegetable oils by direct gas chromatography. A large sample of oil is diffused on glass wool in an injection port liner. After the liner is inserted in the injection port, the volatiles are rapidly swept into the column of the gas chromatograph for analysis.

Preparation of petroselinic acid

Petroselinic acid of a grade which is suitable for most laboratory applications has been prepared by a single crystallization of the mixed fatty acids of parsley seed oil from 90% ethanol. A product of higher purity has been prepared from this acid by application of urea segregation techniques for the removal of saturated materials. No evidence of the presence of unsaturated fatty acids other than petroselinic acid was found in either of these samples when their ozonolysis products were examined chromatographically. On the basis of iodine values, assuming the absence of other unsaturated materials, the purities of the two preparations are 96.0 and 99.4%.

Determination of residual solvent in oilseed meals and flours: IV, acetone

A simple volatilization procedure was developed for the determination of residual acetone in oilseed meals and flours. One gram of meal or flour and 0.2 g of water containing 0.4 mg of methanol are added into a 100 ml serum bottle, which is sealed and heated at 70 C for 5 hr in an oven. A 1 ml aliquot of the headspace gas is then analyzed by gas chromatography. The concentration of residual acetone is easily determined by comparing the ratio of the peak areas of acetone to methanol of the chromatogram with a calibration curve. Results are reproducible within ± 10%, and concentrations of a few ppm can be detected. This technique is much simpler and requires less operator time than other procedures available.

Isolation of methylcis, cis-5, 13-docosadienoate fromLimnanthes douglasii oil

Methylcis,cis-5,13-docosadienoate has been isolated from the mixed methyl esters of the fatty acid moiety ofLimnanthes douglasii oil by a combination of low temperature fractional crystallization and fractionation of mercuric acetate adducts. The methyl ester and its free acid have been characterized.

Some derivatives of 5-eicosenoic acid

Abstractcis-5-Eicosenoic acid and its methyl ester have been epoxidized. Preparation of an hydroxylactone through lactonizaton of both the 5,6-epoxy acid and the 5,6-dihydroxy acid has been investigated. 5-Eicosenoic acid has also been converted to γ-lactone through use of perchloric orp-toluenesulfonic acid. The preparation of several other related new compounds is described.

Derivatives of jojoba oil as plasticizers for vinyl polymers and Buna-N rubber

SummaryTen maleinated jojoba oil derivatives were screened as plasticizers in a standard polyvinyl resin formulation and as softeners for Buna-N rubber. Three of these, the methyl and butyl esters and hydrogenated methyl esters of maleinated jojoba acids, were comparable to the reference standard, DOP, as primary plasticizers for the vinyl resin. Three others were satisfactory only as secondary plasticizers. Six of the derivatives were comparable to the reference softener, dibutyl sebacate, as softeners in a Buna-N formulation and yielded rubbers meeting the low temperature flexibility requirements (−40°C.) of the automotive industry. Two of the six, those made with the butyl and hydrogenated butyl esters of maleinated jojoba acids, met the still more stringent low-temperature requirements of the aircraft industry (−55°C.).In general, hydrogenation of a derivative adversely affected its compatibility in either the vinyl copolymer or the Buna-N formulations.

Improved procedure for cleaning glassware used in determining the stability of fats and oils by the active oxygen method

SummaryGlassware cleaned with a synthetic detergent instead of hot or cold chromic-sulfuric acid leads to improved reproducibility of the stability of fats and oils determined by the active oxygen method. When the glassware used in this method is cleaned with hot chromic-sulfuric acid, chromium compounds are absorbed within the glass walls and subsequently diffuse into the oil or fat thereby leading to erratic results. A method is described for cleaning the glassware used with the fat stability method which has given reliable results in the hands of the authors for more than a year, during which it has been in almost daily use.