Composition of the carbonyl compounds of extraction cottonseed meal
SummaryOn the basis of a quantitative analysis of the volatile carbonyl compounds present in acetone-treated meal it has been shown that they contain a total of about 11 compounds, the main ones of which are acetone and mesityl oxide.It has been established that the moist heat treatment of extraction meal does not lead to the complete elimination of these compounds, and under severe conditions it actually leads to an increase in the amount of carbonyl compounds through degradation of, mainly, the fatty fraction of the meal.The amount of assimilable lysine in the meal decreases simultaneously.
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.
Determination of residual solvent in oilseed meals and flours: II. 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.