Distribution of aroma volatile compounds in tangerine hybrids and proposed inheritance.

BACKGROUND: With the desirable combination of sugars and acids, volatile compounds contribute to the essential organoleptic attributes of citrus. This study evaluated the aroma volatiles of 20 tangerine hybrids of the University of Florida breeding program. Volatiles were sampled from hand-squeezed juice by headspace solid-phase microextraction (SPME), and analyzed by gas chromatography-mass spectrometry. Principal component analysis (PCA) and cluster analysis (CA) were used to find similarities among samples due to volatile composition with effect of genetic background. RESULTS: In total, 203 volatiles were detected in all samples. Volatiles in lower amounts were widely distributed among samples and were classified mainly as terpene hydrocarbons and oxygenated compounds, such as aldehydes, esters, alcohols and ketones. PCA, based on relative peak areas (content) clearly separated the samples higher in volatile content, mainly those with sweet orange genetic contributions in their background. CA, based on volatile presence/absence, grouped samples into five clusters, each showing distinctive volatile profiles. CONCLUSION: The genetic background of tangerine hybrids affected volatile composition and content of samples. In general, tangerines were characterized by fewer volatiles (in both quality and quantity) and more aldehydes, and hybrids with sweet orange in their background had more sesquiterpenes and esters, which would likely affect their aroma.

Total antioxidant activity and fiber content of select Florida-grown tropical fruits.

Fourteen tropical fruits from south Florida (red guava, white guava, carambola, red pitaya (red dragon), white pitaya (white dragon), mamey sapote, sapodilla, lychee, longan, green mango, ripe mango, green papaya, and ripe papaya) were evaluated for antioxidant activity, total soluble phenolics (TSP), total ascorbic acid (TAA), total dietary fiber (TDF), and pectin. ORAC (oxygen radical absorbance capacity) and DPPH (1,1-diphenyl-2-picrylhydrazyl, radical scavenging activity) assays were used to determine antioxidant activity. The TSP, ORAC, and DPPH ranged from 205.4 to 2316.7 g gallic acid equiv/g puree, <0.1 to 16.7 micromol Trolox equiv/g puree, and 2.1 to 620.2 microg gallic acid equiv/g puree, respectively. The TAA, TDF, and pectin ranged from 7.5 to 188.8 mg/100 g, 0.9 to 7.2 g/100 g, and 0.20 to 1.04 g/100 g, respectively. The antioxidant activities, TSP, TAA, TDF, and pectin were influenced by cultivar (papaya, guava, and dragon fruit) and ripening stage (papaya and/or mango). Antioxidant activity showed high correlations with levels of TSP compounds (r = 0.96) but low correlations with levels of ascorbic acid (r = 0.35 and 0.23 for ORAC and DPPH data, respectively). The antioxidant activities evaluated by both ORAC and DPPH showed similar trends where red guava and carambola exhibited the highest and sapodilla and green papaya exhibited the lowest levels. Guava and mamey sapote exhibited the highest TDF and pectin levels. Many of the tropical fruits were shown to contain an abundance of hydrolyzable tannins, ellagic acid conjugates, and flavone glycosides. Preliminary descriptions are given of the phenols in red/white pitaya (dragonfruit), lychee, and mamey sapote, these fruit being thus far uncharacterized in the literature.

Volatile components and aroma active compounds in aqueous essence and fresh pink guava fruit puree (Psidium guajava L.) by GC-MS and multidimensional GC/GC-O.

Characterization of the aromatic profile in commercial guava essence and fresh fruit puree by GC-MS yielded a total of 51 components quantified. Commercial essence was characterized to present a volatile profile rich in components with low molecular weight, especially alcohols, esters, and aldehydes, whereas in the fresh fruit puree terpenic hydrocarbons and 3-hydroxy-2-butanone were the most abundant components. In the olfactometric analyses totals of 43 and 48 aroma active components were detected by the panelists in commercial essence and fruit puree, respectively. New components were described for the first time as active aromatic constituents in pink guava fruit (3-penten-2-ol and 2-butenyl acetate). Principal differences between the aroma of the commercial guava essence and the fresh fruit puree could be related to acetic acid, 3-hydroxy-2-butanone, 3-methyl-1-butanol, 2,3-butanediol, 3-methylbutanoic acid, (Z)-3-hexen-1-ol, 6-methyl-5-hepten-2-one, limonene, octanol, ethyl octanoate, 3-phenylpropanol, cinnamyl alcohol, alpha-copaene, and an unknown component. (E)-2-Hexenal seems to be more significant to the aroma of the commercial essence than of the fresh fruit puree.

Aroma active components in aqueous kiwi fruit essence and kiwi fruit puree by GC-MS and multidimensional GC/GC-O.

Gas chromatography-mass spectrometry (GC-MS) and multidimensional gas chromatography olfactometry (GC/GC-O) were utilized to study the aroma profile and the aroma active components of commercial kiwi essence and the initial fresh fruit puree. Totals of 29 and 33 components were identified and quantified in the essence and the puree, respectively. Ten components were quantified for the first time as constituents of the kiwi fruit including 3-penten-2-ol, 3-hydroxy-2-butanone, 3-methyl-2-butenal, 2-hexanol, nonanal, 3-methyl-1-butanol, 2-methyl-1-butanol, 3-methyl-2-butanone, 3-methyl 3-buten-2-one, and octane. Analysis of these samples by multidimensional gas chromatography-olfactometry (GC-O) allowed for the identification of >80% of the aroma active components present at level traces in this fruit. A total of 35 components appear to contribute to the aroma of kiwi fresh puree and its aqueous essence. Components described for the first time as constituents of the aroma profile in this fruit were 2-ethylfuran, 3-methyl-1-butanol, 2-cyclohexen-1-one, (E,E)-2,6-nonadienal, diethyl succinate, and hexyl hexanoate.

Characterization of the aromatic profile in aqueous essence and fruit juice of yellow passion fruit (Passiflora edulis Sims F. Flavicarpa degner) by GC-MS and GC/O.

Chemical characterization by gas chromatography-mass spectometry (GC-MS) of the aromatic profile of yellow passion fruit essence and the juice of the fruit yielded a total of 62 and 34 components, respectively. Four new components have been identified and quantified for the first time in this fruit: 3-methyl-2-butanone; ethyl lactate (quantified only in the fruit juice); diethyl malonate (quantified only in the essence); and 3-penten-2-ol (quantified in both samples). Analysis of these samples by gas chromatography/olfactometry (GC/O) yielded a total of 66 components which appear to contribute to the aroma of passion fruit juice and its aqueous essence. Of these, four could not be quantified by GC-MS: acetic acid, ethyl propionate, ethyl 3-oxobutyrate, and propyl hexanoate. New components were described for the first time as constituents of the aromatic profile in this fruit including acetal, 1,3-dimethyl benzene, and 2-methylbutyl hexanoate. Aroma extract dilution analysis (AEDA) allowed for the detection of the most potent odorants in the commercial essence (2-methylbutyl hexanoate and hexyl hexanoate) and in the fresh juice (1,3-dimethyl benzene and 2-methylbutyl hexanoate). 2-Methylbutyl hexanoate, considered as one of the most potent odorants in this fruit, has been described for the first time as an aromatic constituent of yellow passion fruit.