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.

No abstract

Factors affecting the rate of oxidation of nitric oxide myoglobin to metmyoglobin have been studied. Three distinct pseudo-first-order mechanisms were observed: an autoxidation, an oxidation by nitrous acid, and a photo-oxidation.The autoxidation was not affected by pH within the range 5.0 to 7.5 or by nitrite in the absence of nitrous acidi.e., above pH 6.3. The Qm of autoxidation was 5.0.The rate of oxidation by nitrous acid was directly proportional to the square of the nitrous acid concentration, and was therefore markedly influenced by nitrite concentration and by pH.The rate of photo-oxidation was dependent on light intensity and temperature (Q = 1.6), and decreased slightly with increasing acidity. Nitrite reduced the rate slightly at pH levels above pH 6.3, but increased it progressively WINE CONSTITUENTS with increasing acidity from pH 6.3 to 5.4. Evidence is presented that the photo-oxidation proceeds by an active molecule mechanism and not by a lightcatalyzed dissociation.

SIR: After a hydroboration reaction mixture was analyzed by gas chromatography, subsequent analysis on this column of our neutral fraction revealed that we did not obtain our expected gas chromatographic pattern. The peaks corresponding to the alcohols were completely missing.Knowing that primary and secondary alcohols will react with boric acid ( I ) , we theorized that the boric acid present in the hydroboration misture had removed the alcohols.

The mass spectra of three bicyclic y-lactones have been studied, and the fragmentation pathways have been proposed with the aid of accurate mass measurements and metastable transitions. An unusually low [M -CH,] ion and the presence of an abundant [M -C,H,] ion in the mass spectrum of dihydroactinidiolide u ere interpreted as a possible rearrangement involving a methyl migration. The eliminations of methyl radical, carbon monoxide and ketene are important processes in many cases.