The Girard-T reagent was used to recover the aldehydes from cold-pressed lemon, orange and grapefruit oils for subsequent quantitative gas chromatographic analysis. Optimum conditions for analysis were worked out with a known mixture of citral and the saturated aliphatic aldehydes which occur in major concentration in lemon oil. Isopropanol was used in the preparative step to eliminate acetal formation and isopentane in the final extractions to reduce losses of the lower-molecular-weight aldehydes during vacuum concentration of the sample for gas chromatographic analysis. Typical analyses are given for samples of domestic cold-pressed citrus oils.

SUMMARY The monoterpene hydrocarbon composition of 29 non‐citrus essential oils was determined with silicic acid chromatostrips and gas‐liquid chromatography. Data arc presented showing the total monoterpene hydrocarbon content and the relative proportions of 19 of these compounds in each oil.

°Paste titration method for acidity. de-ashed oxidized starches based on the corrected acidity is believed to be a better approximation to the "real carboxyl content" than calculations based on the uncorrected acidity.

The direct -effect of the free fatty acids themselves on flavor and aroma would depend on the kind of acids liberated. The metabolic liberation of fatty acids to supply energy in the depleted live pig may produce a pattern of acids different from that produced by autolysis in post-mortem fat. Relation of fat acidity to depletion was evident from the following observation. In the 14 back fat samples having acid numbers above 0.40, the liver glycogen values in milligrams per gram were distributed as follows: 7 at 2 or lower; 2 at 4 to 8; 3 at 12; and 2 at 25. In the 16 samples having acid numbers below 0.25, the liver glycogen values were: 13 at 41 to 97; lat28; and 2 at 12 to 14.A scattergram for fat flavor and acid numbers after a 24-week frozen storage (Figure 2) gave a strikingly different pattern from that shown in Figure 1. At that time, traces of peroxide had appeared in only four samples, but the flavor had deteriorated so far that 81% of the points were located in the region comparable to area D (Figure 1). Free fatty acid had increased 50 to 100% in most samples.

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