Chi-Kuen Shu

Volatile Components of Pocket Melon (Cucumis melo L. ssp. dudaim Naud.)

ABSTRACT The volatile components of Cucumis melo ssp. dudaim (pocket melon), which were isolated by continuous extraction with isopentane, were identified by a combination of retention indices and GC/MS. Forty-eight constituents were identified in the aroma concentrate, from which hexanol (11.52%), chavicol (11.33%), (Z)-3-hexenol (6.84%), benzyl alcohol (3.54%) and eugenol (3.48%) were found to be the major constituents. The amount of chavicol found in the aroma concentrate was thought to contribute to the unique aroma character of the pocket melon.

Essential Oil of Torreya taxifolia Arnott

ABSTRACT The leaf oil of the Florida torreya, Torreya taxifolia, an endangered species, which was obtained by simultaneous steam distillation-solvent extraction was analyzed by GC and GC/MS. Although 24 components were identified in the oil, it was found to be hydrocarbon-rich with limonene (40.78%), α-pinene (7.59%), (E)-β-farnesene (6.16%), and δ-cadinene (6.60%) being in greatest abundance.

Temperature Effect on the Volatiles Formed from the Reaction of Glucose and Ammonium Hydroxide: A Model System Study

Summary A study of the reaction between glucose and ammonium hydroxide revealed that in general, the number and amount of volatiles increased as the reaction temperature increased from 75 to 150°C. At low temperatures, imidazole formation was predominant, while at higher temperatures the predominant compounds were alkyl pyrazines and hydroxyalkyl pyrazines. Positive identification of the hydroxymethyl pyrazines was confirmed by synthesis. As the products obtained from the reactions between glucose/NH4OH and glyceraldehyde/NH4OH were very similar, this supports the postulate that the initial step in glucose degradation is glyceraldehyde formation. It is proposed that hydroxymethyl dihydropyrazine generated from glyceraldehyde may follow oxidation and dehydration pathways to form 2-hydroxymethyl pyrazine and methyl pyrazine, respectively.

Chemical Composition of the Essential Oil of Pycnanthemum floridanum E. Grant and Epling

ABSTRACT The essential oils of two clones of Pycnanthemum floridanum, an endemic species in N. America, were examined by GC and GC/MS. Forty constituents were identified in the oils, of which menthone (32.15%), pulegone (39.83%) and piperitone (10.43%) were the major constituents of one clone, while the predominant components of the second clone were neomenthol (13.72%) and pulegone (59.97%).