Concentrated natural orange essences, commercially recovered in aqueous solutions, have aided in investigations of the volatile flavor of citrus juices. Analyses of chemical components, obtained in organic extracts, were performed by programmed temperature gas chromatography (PTGC). Retention temperature studies of the chemical spectrum employing two principal stationary phases, DEGS and Carbowax 20M, supplied tentative identification and peak assignments for 43 compounds. Application of a subtractive type analysis where the carbonyl constituents were removed chemically provided a less complex material for study. Improved PTGC resolution of the carbonyl-free essence facilitated additional peak assignments.

SUMMARY The flavor of orange juices was studied objectively through analyses of recovered volatile materials. Organic extracts of freshly recovered volatiles from juices of established varieties were shown with programmed‐temperature gas chromatography (PTGC) and thermal conductivity detection to contain 40–50 components. Aroma profiles of the different juices were obtained with a programmed‐temperature flame ionization gas chromatograph. Comparative evaluations were conducted of the flavor and aroma patterns of three varieties of Florida oranges: Hamlin, Pineapple, and Valencia. Preliminary investigation revealed no significant qualitative differences among varieties in gross analyses obtained with thermal conductivity an the ionization detection system using PTGC. Quantitative differences appeared responsible for the flavor differences noted among varieties. Analyses showed some compositional differences among varieties in control juices, peel‐oil‐free juices, their respective juice essences, and peel oils. The presence of certain chemical constituents in the juice was directly related to the peel oil. No significant qualitative differences existed in similarly prepared samples from different varieties. Some specific chemical identification and the methods used are outlined.

Alcohols and volatile organic acids were isolated from natural orange essence and identified. The alcoholic constituents were removed from carbonyl-free aqueous essence by solvent extraction and column chromatography, while the organic acids were separated by steam distillation. Programmed temperature gas chromatography (PTGC), infrared analysis, and paper chromatography of the alcohols and alcohol derivatives, and PTGC and paper chromatography of the acids furnished confirmations of component identities. The following alcohols and acids were found in natural orange essence: methanol, ethanol, n-propanol, isobutanol, n-butanol, isopentanol, n-pentanol, n-hexanol, 3-hexen-1 -01, linalool, n-octanol, terpinen-4-01, n-nonanol, a-terpineol, n-decanol, citronellol, acetic acid, propionic acid, butyric acid, caproic acid, and capric acid. The presence of the following alcohols and acids was indicated but not confirmed: isohexanol, methyl heptenol, 2-nonano1, nerol, geraniol, carveol, isovaleric acid, valeric acid, isocaproic, and caprylic acid.N RECEST YEARS, the use of chroma-

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