Potential aromatic compounds as markers to differentiate between Tuber melanosporum and Tuber indicum truffles

The Tuber indicum (Chinese truffle) and Tuber melanosporum (Black truffle) species are morphologically very similar but their aromas are very different. The black truffle aroma is much more intense and complex, and it is consequently appreciated more gastronomically. This work tries to determine whether the differences between the aromatic compounds of both species are sufficiently significant so as to apply them to fraud detection. An olfactometric evaluation (GC–O) of T. indicum was carried out for the first time. Eight important odorants were identified. In order of aromatic significance, these were: 1-octen-3-one and 1-octen-3-ol, followed by two ethyl esters (ethyl isobutyrate and ethyl 2-methylbutyrate), 3-methyl-1-butanol, isopropyl acetate, and finally the two sulfides dimethyldisulfide (DMDS) and dimethylsulfide (DMS). A comparison of this aromatic profile with that of T. melanosporum revealed the following differences: T. indicum stood out for the significant aromatic contribution of 1-octen-3-one and 1-octen-3-ol (with modified frequencies (MF%) of 82% and 69%, respectively), while in the case of T. melanosporum both had modified frequencies of less than 30%. Ethyl isobutyrate, ethyl 2-methylbutyrate and isopropyl acetate were also significantly higher, while DMS and DMDS had low MF (30–40%) compared to T. melanosporum (>70%). The volatile profiles of both species were also studied by means of headspace solid-phase microextraction (HS-SPME-GC–MS). This showed that the family of C8 compounds (3-octanone, octanal, 1-octen-3-one, 3-octanol and 1-octen-3-ol) is present in T. indicum at much higher levels. The presence of 1-octen-3-ol was higher by a factor of about 100, while 1-octen-3-one was detected in T. indicum only (there was no chromatographic signal in T. melanosporum). As well as showing the greatest chromatographic differences, these two compounds were also the most powerful from the aromatic viewpoint in the T. indicum olfactometry. Therefore, either of the two chromatographic methods (GC–O or HS-SPME-GC–MS), together or separately, could be used as a screening technique to distinguish between T. indicum and T. melanosporum and thus avoid possible fraud.     

Key aroma compounds identified in Cheddar cheese with different ripening times by aroma extract dilution analysis,odor activity value,aroma recombination,and omission

To determine the odor-active compounds in Cheddar cheeses with different ripening times (6, 10, and 14 mo), 39 potent odorants of Cheddar cheeses were identified with a flavor dilution factor range between 1 and 512 by aroma extract dilution analysis. To further determine their contribution to the overall aroma profile of Cheddar cheeses, odor activity values of 38 odorants with flavor dilution factors ≥1 were calculated. A Cheddar cheese matrix was developed to determine the concentrations and the odor thresholds of these key aroma compounds. The result of the aroma recombinant experiment prepared by mixing the key aroma compounds in the concentrations in which they occurred in Cheddar cheeses showed that the overall aroma profile of the recombinant sample was very similar to that of Cheddar cheese. The main different compounds in Cheddar cheese with different ripening time were acetic acid, butanoic acid, dimethyl trisulfide, methional, hexanal, (E)-2-nonenal, acetoin, 1-octen-3-one, δ-dodecalactone, furaneol, hexanoic acid, heptanal, and ethyl caproate. This study could provide important information for researching and developing Cheddar cheese–related products.     

Compounds Contributing to the Odor of Aqueous Slurries of Soy Protein Concentrate

ABSTRACT: Gas chromatography olfactometry/mass spectrometry (GCO/MS) studies on static and concentrated headspace of the aqueous slurries from soy protein concentrate (SPC) revealed acetaldehyde, methanethiol, hexanal, dimethyl trisulfide (DMTS), and 2-pentyl furan as the most odorous volatiles. Further aroma extract dilution analysis (AEDA) of the volatile extracts identified the following as the odorous substances: hexanal, 2-heptanone, octanal, 2-octanone, 1-octen-3-one, DMTS, 3-octen-2-one, 2-decanone, benzaldehyde, 2-pentyl pyridine and trans, trans -2,4- nonadienal, along with several unidentified odorants. Methanethiol and acetaldehyde, which have low boiling points, were not detected by AEDA, however. This is the first time that acetaldehyde, methanethiol, and dimethyl trisulfide have been identified as primary odorants in SPC.     

Profiling of volatile compounds of Phyllostachys pubescens shoots in Taiwan

This study examined the influence of heating temperature and duration on volatile aromatic components of spring and winter Phyllostachys pubescens shoots using SPME. Results from GC–MS analyses revealed that the main constituents in both bamboo shoots at ambient temperature include methoxy-phenyl oxime, followed by n-hexanol and 3Z-hexenal, which gives a fresh green aroma. Comparing the different compounds, between spring and winter shoots, revealed that spring bamboo shoots at ambient temperature comprise 12.30% methyl salicylate, which provides protection against insect attack, and 9.71% epi-cedrol; while winter bamboo shoots comprise 17.00% 1-octen-3-ol, which produces a distinct mushroom aroma. After heating at 100 °C for 60 min, a marked increase in relative content of benzyl salicylate (43.30%) and a significant decrease in methyl salicylate content in spring bamboo shoots were observed; while the major compound in winter bamboo shoots was n-heneicosane (78.09%) and the content of specific 1-octen-3-ol significantly decreased.     

Effect of addition of commercial rosemary extracts on potent odorants in cooked beef

Solid-phase microextraction-gas chromatography-olfactometry (SPME-GCO) and aroma extract dilution analysis (AEDA) were applied to measure the effects of the addition of two commercial rosemary extracts (RE) on the potent odorants in cooked beef extracts (BE). On the basis of the results of SPME-GCO and AEDA, the addition of RE imparted sweet and floral notes to BE as a result of the addition of esters and terpenes of RE. In addition, RE suppressed the formation of odorants derived via lipid oxidation and Maillard reactions. The most potent lipid oxidation volatiles consisted of 1-octen-3-one (mushroom-like), (E)-2,4-epoxy-(E)-2-decenal (metallic), and eight different aldehydes (fatty). The Maillard reaction volatiles, necessary for typical cooked beef flavor, included compounds with meaty [2-methyl-3-furanthiol, 2-methyl-3-(methylthio)furan, 2-methyl-3-(methyldithio)furan], roasty (2-furanmethanethiol), caramel-like [4-hydroxy-2,5-dimethyl-3(2H)-furanone], baked potato-like [3-(methylthio)propanal], and spicy [3-hydroxy-4,5-dimethyl-2(5H)-furanone] attributes. The suppressive effects of RE may be caused by the action of antioxidative substances in RE alone or in combination with the pH increase in BE induced by the matrix components of RE.     

Influence of Maturity on the Volatile Aroma Compounds from Fresh Pacific and Great Lakes Salmon

Volatile aroma compounds from freshly harvested prime and spawning-condition salmon (Oncorhynchus sp.) from the Pacific Ocean (chi-nook, sockeye, chum, coho and pink) and the Great Lakes (chinook, coho and pink) were quantitatively measured. Both prime and spawning-condition salmon had 1-octen-3-one, 1,5-octadien-3-one, 1-octen-3-ol, 1,5-octadien-3-ol, 2-octen-1-ol, and 2,5-octadien-1-ol which contributed distinct and characteristic plant-like aromas to the fish. More pronounced aromas of spawning-conditions almon were attributed to greater concentrations of the 8-carbon compounds in combination with occurrence of (E)-2-nonenal, (E)-2,(Z)-6-nonadienal, 6-nonen-1-ol, and 3,6-nonadien-1-ol which added sweet, cucumber- or melon-like aroma notes. The 9-carbon compounds may have resulted from biochemical regulation of physiologically active lipid-derived substances which activate mucus secretion in salmon approaching sexual maturity.     

Characterization of the key aroma compounds in beef extract using aroma extract dilution analysis

Aroma extract dilution analysis (AEDA) of an ether extract prepared from beef extract (BE) and subsequent identification experiments led to the determination of seven aroma-active compounds in the flavor dilution (FD) factor range of 32–128. Omission experiments to select the most aroma-active compounds from the seven aroma compounds suggested that 2,3,5-trimethyl pyrazine, 1-octen-3-ol, 3-methylbutanoic acid, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were the main active compounds contributing to the aroma of BE. Aroma recombination, addition, and omission experiments of the four aroma compounds in taste-reconstituted BE showed that each compound had an individual aroma profile. A comparison of the overall aroma between this recombination mixture and BE showed a high similarity, suggesting that the key aroma compounds had been identified successfully.     

Evaluation of potent odorants in heated egg yolk by aroma extract dilution analysis

Egg yolk was extracted using the method of Likens-Nickerson (simultaneous distillation/extraction). The resulting aroma extract, which smelled characteristic of heated egg yolk was analysed by aroma extract dilution analysis and gas chromatography–mass spectrometry. Of 41 odorants that were detected, 19 could be identified. Compounds with high flavour dilution factors were methional, phenyl acetaldehyde, 2-acetyl-1-pyrroline, heptanal, 1-octen-3-one and (E,E)-2,4-decadienal. Strecker degradation of methionine, phenylalanine and proline, as well as autoxidation of phospholipid-bound linoleic and arachidonic acids are proposed as the major factors for egg yolk flavour formation.     

Analysis of free and bound aroma compounds of pomegranate (Punica granatum L.)

Volatile aroma compounds were isolated from pomegranate arils by high vacuum distillation (HVD) and solvent extraction with diethyl ether. The HVD distillate exhibited a fresh-fruity and characteristic pomegranate aroma while the total ether extract was devoid of this note in its concentrate. Gas chromatography–mass spectroscopy (GC–MS) analysis revealed the presence of 3-octen-1-yl acetate, trans-3-hexen-1-ol, hexanol and 2-methyl pentanol only in the high vacuum distillate. Ether extract was dominated by 2-heptanol, 2-nonanol and 3-methyl-2-butanol. Based on olfactometric analysis of the HVD isolate, 3-octen-1-yl acetate was identified as the key odorant of pomegranate. Chemical synthesis of this compound, further confirmed its structure. Among the bound aroma compounds, 2-phenylethanol (40%), alpha-terpineol (4.53%) and 2-heptanol (6.35%) were identified as the major compounds existing as glycoconjugates. Identification of the character impact compound and the occurrence of glycosidic precursors in pomegranate are being reported here for the first time.     

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste,with special emphasis on effect of fish species and meat washing

The present study investigated the suitability of four species of trash fishes for the production of fish miso, a Japanese fermented fish meat paste compared with soy and rice miso from the point of view of product aroma. The effect of washing fish meat on finished product was also evaluated. Headspace volatiles for different miso samples were analyzed by using solid phase microextraction (SPME) technique. A total of 107 volatile compounds have been identified, where 94 were common for all the miso samples. Considering the lower threshold perception and higher odour active values 2-methylbutanal, 3-methylbutanal, methional, isoamyl acetate, dimethyl disulfide, dimethyl trisulfide, 2,3-butanedione, 3-methylethyl butanoate, 3-methyl-1-butanol, ethyl hexanoate, 1-octen-3-ol, heptanol, heptanal and 2-undecanone were identified as key compounds for the miso products. Principal components analysis (PCA) and hierarchical cluster analysis (HCA) of headspace volatiles clearly elucidated the relationship amongst different miso samples based on fish species and effect of fresh water washing of meat on aroma of finished product.     

Melittis melissophyllum L. subsp. melissophyllum (Lamiaceae) from central Italy: A new source of a mushroom-like flavour

1-Octen-3-ol is the most important C8 mushroom aromatic compound produced by many species of edible fungi and is also an aroma component in several food and beverages products. Under this view, the essential oil of flowering aerial parts of Melittis melissophyllum subsp. melissophyllum (Lamiaceae) growing in central Italy, obtained by hydrodistillation was characterised by GC–FID and GC–MS. This oil contained extremely high amount of the mushroom-like aroma component 1-octen-3-ol (43.6–54.2%), and could be considered as a new natural product for the use as flavouring agent in the food industry. Furthermore, headspace analysis suggested that this aromatic compound is only present in low concentration in the plant part, and is primarily formed in higher amount during hydrodistillation of this material.     

Characterisation of the mushroom-like flavour of Melittis melissophyllum L. subsp. melissophyllum by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC–FID) and gas chromatography–mass spectrometry (GC–MS)

1-Octen-3-ol is an eight-carbon alcohol responsible for the unique fungal aroma and flavour of edible mushrooms. Among Lamiaceae plants, the highest concentration of this molecule was detected in Melittis melissophyllum subsp. melissophyllum growing in central Italy. On this basis in the present study a HS-SPME coupled with GC–FID and GC–MS was performed to check the influence of several analytical parameters on the amount of 1-octen-3-ol from the plant matrix. Results showed that 1-octen-3-ol is produced in the plant matrix independently from the harvesting time by an enzyme reaction that is enhanced by the optimisation of the extraction conditions (extraction temperature, 40 °C; water addition, 20 μl; extraction time, 30 min; particle size, 1 mm, sample amount, 30 mg). These findings revealed that M. melissophyllum is the first example of a plant, that under appropriate conditions, may be used as a mushroom-like flavouring agent in food products.     

Aroma components of American country ham

ABSTRACT:  The aroma-active compounds of American country ham were investigated by using direct solvent extraction-solvent assisted flavor evaporation (DSE-SAFE), dynamic headspace dilution analysis (DHDA), gas chromatography-olfactometry (GCO), aroma extract dilution analysis (AEDA), and gas chromatography-mass spectrometry (GC-MS). The results indicated the involvement of numerous volatile constituents in the aroma of country ham. For DHDA, 38 compounds were identified as major odorants, among them, 1-octen-3-one, 2-acetyl-1-pyrroline, 1-nonen-3-one, decanal, and (E)-2-nonenal were the most predominant, having FD-factors ≥ 125 in all 3 hams examined, followed by 3-methylbutanal, 1-hexen-3-one, octanal, acetic acid, phenylacetaldehyde, and Furaneol™. For the DSE-SAFE method, the neutral/basic fraction was dominated by 1-octen-3-one, methional, guaiacol, (E)-4,5-epoxy-(E)-decenal, p-cresol as well as 3-methylbutanal, hexanal, 2-acetyl-1-pyrroline, phenylacetaldehyde, and γ-nonalactone. The acidic fraction contained mainly short-chain volatile acids (3-methylbutanoic acid, butanoic acid, hexanoic acid, and acetic acid) and Maillard reaction products (for example, 4-hydroxy-2,5-dimethyl-3(2H)-furanone). The above compounds identified were derived from lipid oxidation, amino acid degradation, and Maillard/Strecker and associated reactions. Both methods revealed the same nature of the aroma components of American country ham.     

Comparison of the most odour-active volatiles in different hop varieties by application of a comparative aroma extract dilution analysis

Application of a comparative aroma extract dilution analysis on the volatiles isolated from five different hops (Hallertau Perle, Hallertau Hersbrucker Spät, Slowenian Golding, Hallertau Smaragd, US Cascade) revealed linalool and myrcene with the highest Flavour Dilution (FD)-factors in all varieties, followed by 2-isopropyl-3-methoxypyrazine, 3-methylbutanoic acid and geraniol. Some odourants, however, showed high FD-factors only in certain varieties, for example, (5Z)-octa-1,5-dien-3-one and germacrene B in Hersbrucker Spät, (3E,5Z)-undeca-1,3,5-triene in Hersbrucker Spät and Cascade and nonanal in Cascade. The overall odour profile of the Cascade sample clearly differed from the other varietes, and was dominated by a black currant like odour note. The identification experiments revealed 4-methyl-4-sulfanylpentan-2-one, so far unknown as hop constituent, as key contributor to this odour. In addition, an odour-active undecatetraene was present, in particular, in Perle and Cascade. Synthesis and structural assignment of the four stereoisomers of (3E)-undeca-1,3,5,9-tetraene allowed the identification of the fresh, pineapple-like smelling compound as (3E,5Z,9E)-undeca-1,3,5,9-tetraene. Among the four isomers synthesised, this compound showed by far the lowest odour threshold of 0.01 ng/L in air.     

Comparative evaluation of potent odorants of boiled beef by aroma extract dilution and concentration analysis

 After boiling, beef was extracted with dichloromethane, and the volatile fraction including the solvent was distilled from the non-volatile material. The distillate was divided into two portions; one-half was subjected to aroma extract dilution analysis (AEDA), and the other to aroma extract concentration analysis (AECA). In the latter case, the AECA was accompanied by a series of gas chromatography-olfactometry (GCO) analyses, whereas in the former (i.e. AEDA) the extract was first concentrated to a small volume and then diluted stepwise for GCO analysis. Both screening procedures confirmed the presence of 32 odorants which were all identified after a 250-fold concentration of the extracts. However, the ranking of the compounds in order of odour potency was different due to losses of the odorants in AEDA. 2-Furfurylthiol and 4-hydroxy-2,5-dimethyl-3(2H)-furanone followed by 2-methyl-3-furanthiol and a group containing 3-mercapto-2-pentanone, 1-octen-3-one and (E)-2-non-enal were indicated by AECA to be the most potent odorants of boiled beef. Received: 15 March 1996     

Effects of two enzyme extracts of <Emphasis Type="Italic">Aspergillus niger</Emphasis> on green tea aromas

Green tea was investigated in terms of its aroma changes induced by two enzyme extracts of Aspergillus niger, i.e., crude enzyme extracted from fermentation using tea stalk medium (CETSM) and crude enzyme yielded in potato dextrose medium. The result showed that the former had significant effects on sensory indexes and volatile constituents, with significant increases in toasty and mushroom notes, while the latter had little influence on the aforementioned indexes. In addition, the volatile constituents were significantly affected; in particular, the contents of cis-3-hexenol, 1-octen-3-ol, eucalyptol, hexanol, and benzaldehyde increased. Furthermore, gas chromatography–olfactometry (GC–O) analysis showed that an increase in 1-octen-3-ol strengthened the mushroom note. These results indicate that CETSM contains some novel enzymes that can modify the aroma profile of green tea. This study also provides valuable information and suggestions to use fermented enzymes to modify food aromas.     

Non-toxic Salvia sclareoides Brot. extracts as a source of functional food ingredients: Phenolic profile,antioxidant activity and prion binding properties

Salvia sclareoides is an aromatic herb native to Portugal, of which phenolic content (Folin–Ciocalteau method), chemical profile (HPLC/DAD), antioxidant activity (DPPH, β-carotene/linoleic acid assays), acute toxicity (MTT method, adapted for non-adherent cells), genotoxicity (short-term chromosomal aberration assay) and prion binding properties were evaluated in the acetone, water, ethanol, methanol and n-butanol extracts. The latter presented the highest phenolic content and antioxidant activity (DPPH assay), and was the single one with the flavonoids (+)-catechin, kaempferol O-glucoside and quercetin. Vanillic acid was the major component of all extracts but gallic, gentisic, caffeic, syringic, coumaric and ferulic acids were also found in some extracts. Only the n-butanol extract had components binding to the cellular form of human prion protein detected by NMR which showed specificity for two regions of the folded domain and for the unstructured N-terminal region. Extracts were not cytotoxic nor genotoxic, reinforcing the potential of S. sclareoides for nutraceutical purposes.