Harold P. Dupuy

Antimicrobial activity of some ricinoleic acid oleic acid derivatives

Ricinoleic and acid oleic acid derivatives were screened for their antimicrobial activity, under optimum growing-conditions, against several species of bacteria, yeasts, and molds. Several ricinoleic acid derivatives and petroselinic (iso-oleic) acid exhibited considerable activity; in fact, their activity against some micro-organisms was comparable to sorbic and 10-undecenoic acid, known antimicrobial agents, as indicated by this test.

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.

Rapid quantitative determination of residual hexane in oils by direct gas chromatography

A simple, direct, gas chromatographic technique is described for the quantitative determination of residual hexane in extracted vegetable oils. The method if rapid and sensitive to one ppm hexane. The inlet liner of a gas chromatograph was packed with 1 1/2 in. glass wool, and 25 mg oil was added onto it. The sample was capped with a small plug of glass wool, and the liner was inserted in the heated inlet of the gas chromatograph. Residual hexane rapidly eluted onto the Poropak P column by heat, and carrier gas was resolved in 20 min by temperature programing between 70–180 C. The method appears useful for monitoring continuous solvent removal processes.

Rapid instrumental technique for the analysis of volatiles in salad dressing

A simple, rapid, efficient procedure for analyzing the volatile components in salad dressings is described. A unique inlet system, used in conjunction with gas chromatography and mass spectrometry, provides an objective, tangible profile of volatiles characteristic of the product. The individual components may be identified to qualify more effectively the odor and flavor quality of the specimen.

A rapid procedure for the determination of residual hexane in oilseed meals and flours

A rapid and direct gas chromatographic procedure is described for the quantitative determination of residual hexane in finely ground oilseed meals and flours. A 0.04 g sample of meal or flour is added between two small plugs of glass wool in a liner of the injection port of a gas chromatograph. The liner with the sample is placed in the heated injection port and firmly secured, and 80 μl of water is immediately injected just above the glass wool which covers the sample. Volatiles which are rapidly eluted from the sample are then analyzed by temperature-programmed gas chromatography on a 2 ft × 1/4 in. Porapak P column. The results are comparable to the results obtained by the simple and efficient but more time consuming volatilization procedure. Since results are obtained within 20 min, this rapid procedure is very useful in monitoring desolventization processes.

Elimination of the halphen response of cottonseed oils in conjunction with deodorization

Two simple but effective pilot-plant processes were developed to produce Halphen-negative cottonseed oil. Both involve treatment of the oil with cottonseed fatty acids in a conventional batch type of deodorizer in conjunction with deodorization. In one process, in which the acids were added to the oil, the cyclopropenoids were inactivated in as short a time as 5 min after the oil reached the maximum temperature of 450–455 F. In the other, in which the acids were generated in situ, the oil did not become Halphennegative until about an hour and 45 min after it reached maximum temperature. The excess acids produced by both methods were readily removed during conventional deodorization. In contrast, deodorization alone reduced the cyclopropenoid content of the oil to a low level (0.02%) but did not render it Halphen-negative even after 3 hr at maximum temperature.These new processes are directly applicable for use by refineries that have the batch type of deodorizers. For refineries that operate continuous or semicontinuous deodorizers, it should be relatively simple to design preheating vessels or heat exchangers to inactivate partially or completely the cyclopropenoids before deodorization.

Determination of residual solvent in oilseed meals and flours: III. Isopropanol

A relatively simple volatilization procedure is described for the determination of residual isopropanol in oilseed meals and flours. A 1 g sample is placed in a 100 ml serum bottle, 200 µl of distilled water containing 0.075 mg of ethanol is added and the bottle is sealed with a rubber stopper and heated at 110 C for 1 hr. A 2 ml aliquot of the headspace gas is analyzed by gas chromatography using the added ethanol as an internal standard. Values determined by this procedure for three cottonseed, two peanut and two fish meals or flours which had been processed with isopropanol, ranged from 10 to 12,000 ppm and were of the same order of magnitude as values determined by a modification of the Todd azeotropic distillation procedure. Advantages of the volatilization over the azeotropic distillation procedure are that less operator and gas chromatograph time are required per analysis.

Determination of mesityl oxide and diacetone alcohol in oilseed meals and flours

Two methods were compared for quantitative determination of trace amounts of mesityl oxide and diacetone alcohol in acetone-extracted oilseed meals and flours. In the first, a simple, rapid and direct gas chromatographic procedure, a 0.04 g sample of oilseed meal or flour was placed between 2 small glass wool plugs in a liner of the injection port of a gas chromatograph. Water-saturated molecular sieve 5A (1.1 g) was added over the glass wool sandwich, and the liner was placed in the heated injection port and firmly secured. Mesityl oxide and diacetone alcohol, and other volatiles, were eluted rapidly from the sample onto the column by the combined action of heat, moisture, and carrier gas. The components then were resolved readily by temperature-programed gas chromatography on a 2 ft × 1/4 in. Porapak P column. The second method, which is time consuming and tedious, is a modification of the Todd azeotropic distillation procedure and was included, for comparison, as a conventional measure of the concentrations of mesityl oxide and diacetone alcohol. Samples of oilseed meals and flours were analyzed by both methods. The results are compared, and the relative merits of the two procedures are discussed.