Fresh juices of four Italian cultivars of lemons (Citrus limon Burm) have been analyzed by headspace solid phase microextraction coupled to gas chromatography and gas chromatography-mass spectrometry (GC-MS). The best results have been obtained with the 2 cm 50/30 microm divinylbenzene/carboxen on poly(dimethylsiloxane) fiber, using a homogenization time of 1 h at 40 degrees C and a sampling period of 30 min. A total of 35 volatile compounds have been identified by GC-MS, and their relative amounts have been calculated by adding internal standard to the samples. Differences in composition of lemon juices volatile components have been observed. Verdello Siracusano lemon juice has the highest amount of volatile compounds (50.28 mg/L), followed by Interdonato (8.39 mg/L), Primo Fiore Capo d'Orlando (5.75 mg/L), and Femminello Siracusano (2.62 mg/L) juices. Volatile compounds mainly consist of mono- and sesquiterpene hydrocarbons and oxygenated molecules (aldheydes, monoterpene alcohols, and monoterpene esters). Headspace solid phase microextraction coupled to a gas chromatograph equipped with a specific sulfur detector, a sulfur chemiluminescence detector, let us detect and quantify dimethyl sulfide compound at the microgram/liter level in lemon juices.

No abstract

No abstract

The volatile constituents of babaco fruit (Curicu penfagonu Heilborn) were investigated. Two different methods of isolation of the volatiles were employed: (a) reduced pressure steam distillation followed by dichloromethane extraction: (b) direct extraction of filtered babaco pulp with diethyl ether. HPLC fractionation of the extracts was carried out. The extracts were analysed by dual capillary gas chromatography and combined capillary GC-MS. The identified volatiles included 9 hydrocarbons, 20 alcohols, 9 carbonyls, 9 acids, 60 esters, 3 lactones, 2 sulphur and 7 miscellaneous components. Quantitative analysis of the major components (butan-1-01 and hexan-1-01) showed similar results for the two isolation methods. Combined GC-sensory analysis was carried out: of the 21 main odours detected, 18 were tentatively assessed by linear retention index comparison with authentic chemical standards. The aroma of babaco appears to be due to the collective effect of a number of components.