Diana Cristina Sinuco

Characterization of the Key Aroma Compounds in Pink Guava (Psidium guajava L.) by Means of Aroma Re-engineering Experiments and Omission Tests

Seventeen aroma-active volatiles, previously identified with high flavor dilution factors in fresh, pink Colombian guavas (Psidium guajava L.), were quantified by stable isotope dilution assays. On the basis of the quantitative data and odor thresholds in water, odor activity values (OAV; ratio of concentration to odor threshold) were calculated. High OAVs were determined for the green, grassy smelling (Z)-3-hexenal and the grapefruit-like smelling 3-sulfanyl-1-hexanol followed by 3-sulfanylhexyl acetate (black currant-like), hexanal (green, grassy), ethyl butanoate (fruity), acetaldehyde (fresh, pungent), trans-4,5-epoxy-(E)-2-decenal (metallic), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel, sweet), cinnamyl alcohol (floral), methyl (2S,3S)-2-hydroxy-3-methylpentanoate (fruity), cinnamyl acetate (floral), methional (cooked potato-like), and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (seasoning-like). Studies on the time course of odorant formation in guava puree or cubes, respectively, showed that (Z)-3-hexenal was hardly present in the intact fruits, but was formed very quickly during crushing. The aroma of fresh guava fruit cubes, which showed a very balanced aroma profile, was successfully mimicked in a reconstitute consisting of 13 odorants in their naturally occurring concentrations. Omission tests, in which single odorants were omitted from the entire aroma reconstitute, revealed (Z)-3-hexenal, 3-sulfanyl-1-hexanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-sulfanylhexyl acetate, hexanal, ethyl butanoate, cinnamyl acetate, and methional as the key aroma compounds of pink guavas.

Characterization of the Aroma-Active Compounds in Pink Guava (Psidium guajava, L.) by Application of the Aroma Extract Dilution Analysis

The volatiles present in fresh, pink-fleshed Colombian guavas ( Psidium guajava, L.), variety regional rojo, were carefully isolated by solvent extraction followed by solvent-assisted flavor evaporation, and the aroma-active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis. The results of the identification experiments in combination with the FD factors revealed 4-methoxy-2,5-dimethyl-3(2 H)-furanone, 4-hydroxy-2,5-dimethyl-3(2 H)-furanone, 3-sulfanylhexyl acetate, and 3-sulfanyl-1-hexanol followed by 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, ( Z)-3-hexenal, trans-4,5-epoxy-( E)-2-decenal, cinnamyl alcohol, ethyl butanoate, hexanal, methional, and cinnamyl acetate as important aroma contributors. Enantioselective gas chromatography revealed an enantiomeric distribution close to the racemate in 3-sulfanylhexyl acetate as well as in 3-sulfanyl-1-hexanol. In addition, two fruity smelling diastereomeric methyl 2-hydroxy-3-methylpentanoates were identified as the ( R,S)- and the ( S,S)-isomers, whereas the ( S,R)- and ( R,R)-isomers were absent. Seven odorants were identified for the first time in guavas, among them 3-sulfanylhexyl acetate, 3-sulfanyl-1-hexanol, 3-hydroxy-4,5-dimethyl-2(5 H)-furanone, trans-4,5-epoxy-( E)-2-decenal, and methional were the most odor-active.

Chemical studies on curuba (Passiflora mollissima (Kunth) L. H. Bailey) fruit flavour.

The odour-active volatiles of curuba fruit (Passiflora mollissima (Kunth) L. H. Bailey) were isolated by solvent assisted flavour evaporation (SAFE). GC-O and GC-MS analyses identified linalool, hexyl acetate, 1,8-cineole, and butyl acetate as key aroma compounds of this fruit. Other odorants relevant because of their contribution to the overall aroma were: 2-methylpropyl acetate, (Z)-3-hexen-1-ol, and (Z)-3-hexenyl acetate. Sulphur compounds, 3-sulfanylhexyl acetate and methional, were reported here for first time as odour-active volatiles in curuba. By HPLC-ESI-MS analyses of glycosidic mixtures and GC-MS analyses of volatiles released enzymatically with a glucosidase, (Z)-3-hexenyl β-D-glucopyranoside and linalyl β-D-glucopyranoside were identified as aroma precursors in P. mollissima fruit. Thermal treatment of the glycosidic mixture at native pH of fruit gave furanoid cis- and trans-linalool oxides, as well as, α-terpineol, compounds that exhibit flowery odour notes. Biogenic relationships among odour-active volatiles and their glycosidic precursors were also proposed.

Quantitation of the odour-active compounds in Andes berry ( Rubus glaucus Benth) fruit using the molecular sensory approach

The odour-active volatiles of Andes berry fruit (Rubus glacus Benth) were isolated by solvent-assisted flavour evaporation. Subsequent gas chromatography–olfactometry and gas chromatography coupled to mass spectrometry analyses and application of stable isotopic dilution analyses allow identifying 2-heptanol and ethyl butanoate as key aroma compounds in this fruit. Other relevant odorants were 4-hydroxy-2,5-dimethyl-3(2H)-furanone and ethyl benzoate, because of their contribution to the overall Andes berry aroma (high OAVs).

Key aroma volatile compounds of gulupa (Passiflora edulis Sims fo edulis) fruit

By application of the aroma extract dilution analysis of gulupa (Passiflora edulis Sims fo edulis), fruit pulp extract obtained by solvent-assisted flavour extraction, and also comparison of chromatographic, spectroscopic (mass spectrum), and odour properties with standards, β-ionone, γ-nonalactone, ethyl butanoate, and ethyl cinnamate were identified as volatiles exhibiting the highest flavour dilution (FD) factor. Among the nineteen odour-active compounds of gulupa, only those showing the highest FD factors were quantified by stable isotope dilution assay. After calculation of odour activity values (OAVs; ratio of concentration to odour threshold in water), ethyl butanoate, ethyl hexanoate, and β-ionone were identified as key aroma compounds in gulupa, responsible for the fruity and floral odour notes.

Flavoromics approach to differentiate three edible Tacsonia (Passifloraceae) fruit species

AbstractThe odour-active compounds of three Tacsonia fruits (Passiflora sp.) species: P. tarminiana, P. mixta and P. tripartita var mollissima, were isolated by headspace solid-phase microextraction and identified by gas chromatography–olfactometry and gas chromatography–mass spectrometry analyses in comparison with standards. Physicochemical and sensory properties were different in the threes species. P. mixta exhibited an intense green, herbal, and seed-like odour; P. tarminiana was characterised by the presence of sweet, acidic, fruity, and floral odour notes, while P. tripartita had a soft sweet, fruity, and aqueous odour. Aliphatic esters and alcohols, and terpenic compounds were predominant in all of these species; being hexyl acetate, hexyl hexanoate, and hexyl butanoate major constituents in all of them. Multivariate analysis of the relevant odorants showed a strong correlation between aroma compounds and classification of Tacsonia species, showing a close correlation among P. mixta and P. tripartita var. mollissima aroma composition. The present methodology is adaptable for the comparative study of Tacsonia subgenus commercial samples, to discriminate if they are pure or hybrids and for their aroma quality evaluation.