The influence of heat on the aroma of cloudberries (Rubus Chamaemorus L.)

Summary The qualitative and quantitative differences between the volatiles of fresh and heated cloudberries have been evaluated and the significance of the differences calculated. 14 new cloudberry volatiles have been identified, including vanillin, methyl vanillate, acetovanillone and 3,5-Dhydroxy-2-methyl-4Hpyran-4-one. During the heating procedure two additional compounds, 3-hydroxypyran-2-one and 2-pyrrolaldehyde, were formed. Comparison of the quantitative data for the heated and unheated samples revealed 21 compounds having significant differences in concentration at or below the 10% level. The concentration of 4-vinylphenol, 2-methoxy-5-vinylphenol, furfural, 5-hydroxymethylfurfural and 3,5-dihydroxy2-methyl-4H-pyran-4-one increased very markedly on heating. The concentrations of 81 compounds in the unheated press juice of cloudberries are given.

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Der Einfluß der Erhitzung auf das Aroma der Moltebeeren (Rubus chamaemorus L.)

Zusammenfassung Die Unterschiede zwischen den flüchtigen Stoffen des frischen und des erhitzten Saftes der Moltebeeren wurden qualitativ und quantitativ untersucht. Dabei wurden 14 neue Verbindungen aufgefunden, wie Vanillin, Vanillinsäuremethylester, Acetovanillon und 3,5-Dihydroxy-2-methyl-4-Hpyran-4-on. Während der Wärmebehandlung wurden zusätzlich 3-Hydroxypyran-2-on und 2-Pyrrolaldehyd gebildet. 21 Komponenten zeigten im unbehandelten und im erhitzten Saft deutliche Gehaltsunterschiede. Die Konzentrationen an 4-Vinylphenol, 2-Methoxy-5vinyl-phenol, Furfurol, 5-Hydroxymethylfurfurol und 3,5-Dihydroxy-2-methyl-4H-pyran-4-on stiegen während des Erhitzens stark an. Schließlich sind die Konzentrationen von 81 Stoffen im unbehandelten Saft angegeben.

     

Flavonolglykoside der Erdbeeren (Fragaria x ananassa Duch.), Himbeeren (Rebus idaeus L.) und Brombeeren (Rubes fruticosus L.)

Summary Leaves and fruits of strawberries (20 cultivars), raspberries (5 cultivars) and blackberries (5 cultivars) examined by us contained exclusively glycosides of kaempferol and quercetin, which have been isolated, in part, in crystalline form. As major glycosides we found the 3--glucuronides, 3--glycosides and 3-xylosylglucuronides. Several 3,7-glycosides could be tentatively identified, though present in minor amounts.High-performance liquid and two-dimensional thin-layer chromatography were used for rapid qualitative and quantitative determination. Differences between examined cultivars could not be detected, except in flavonol glycosides which occur in trace amounts.Zusammenfassung Blätter and Früchte der untersuchten Erdbeeren (20 Sorten), Himbeeren and Brombeeren (je 5 Sorten) enthielten ausschließlich Glykoside des Kämpferols and Quercetins, die zum Teil in kristalliner Form isoliert werden konnten. Als Haupt-Glykoside werden 3--Glucuronide, 3--Glucoside and 3-Xylosylglucuronide gefunden. Als Neben-Glykoside konnten einige 3,7-Glykoside identifiziert werden.Mittels Hochleistungs-Flüssigkeits- and zweidimensionaler Dünnschicht-Chromatographie werden die Flavonolglykoside qualitativ and quantitativ bestimmt. Sortenunterschiede konnten bei diesen untersuchten Kultursorten nicht festgestellt werden, mit Ausnahme der in Spuren vorkommenden Flavonolglykoside.

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13. Mitt.: Henning W, Herrmann K (1980) Z Lebensm Unters Forsch 171:183     

Characterisation of green aroma of raw mango (Mangifera indica L.)

The latex of two varieties of mango, Alphonso and Batali, was collected during the de-stalking of freshly picked matured unripe (raw) fruit. The essential oil of each of the mango latices was isolated by high vacuum distillation at ambient temperature. The major component of each essential oil possessing the characteristic aroma of green mango, was isolated by preparative gas-liquid chromatography and was characterised as cis-ocimene and β-myrcene, respectively.     

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.     

Relationship of aroma and flavour characteristics of mango (Mangifera indica L.) to fatty acid composition

Glyceride content and fatty acid composition of pulp from five commercial varieties of table-ripe mangoes having wide differences in aroma and flavour were studied. In addition, the Alphonso mango was examined at various stages of ripening at two different temperatures. Although the same type of fatty acids were present in all varieties of ripe mango there were differences in quantitative distribution. During the ripening of Alphonso mango at ambient temperature (25 to 30 °C), there was an increase in the glyceride content of the pulp, followed by rapid changes in fatty acid composition and in aroma and flavour, while at low temperature (10 ± 2 °C), where ripening was considerably delayed, there were no appreciable changes in glyceride content and in fatty acid composition of the pulp or in aroma and flavour. A correlation was ascertained between organoleptically evaluated aroma and flavour characteristics of mango pulp and the ratio of palmitic acid to palmitoleic acid.     

Characterization of the odor-active compounds responsible for atypical aroma notes in cocoa (Theobroma cacao L.)

Cocoa is the key raw material in chocolate manufacturing. The quality of cocoa is crucial for the pleasant aroma of the final confectionery products. Ideally, cocoa shows a rich aroma with floral, sour, malty, earthy, and fruity notes. However, chocolate manufacturing companies occasionally report the presence of off-flavors in fermented cocoa at the level of the incoming goods inspection. Among them, moldy-musty and coconut-like notes are frequently observed. It is hard to establish the presence of off-flavors on the base of sensory data only, as it has mainly been done so far, because this type of assessment is very subjective. Therefore, there is a strong need for an objective method based on analytical data to affirm whether a cocoa batch is suitable or not for further manufacturing. To clarify the molecular background of the moldy-musty and the coconut-like notes, the volatiles were isolated from fermented cocoa samples tainted with off-flavors by solvent extraction and solvent-assisted flavor evaporation (SAFE). The odor-active compounds were determined by comparative aroma extract dilution analyses (cAEDA), using flawless cocoa samples as reference. The first part of the investigation was focused on cocoa samples with a moldy-musty off-flavor. Application of cAEDA revealed (-)-geosmin, 4-methoxy-2,5-dimethylfuran-3(2W)-one, 1W-indole, and 3-methyl-1W-indole as potential off-flavor compounds. This compound selection was based on their odor quality and higher flavor dilution factors in the off-flavor cocoa than in the reference sample. Quantitation of the four compounds in nine off-flavor cocoa samples and calculation of odor activity values (OAVs; ratios of the concentrations to the odor threshold values) suggested crucial roles of (-)- geosmin and 3-methyl-1W-indole for the off-flavor. In the chocolate industry, their quantitation can be used to objectively assess the moldy-musty off-flavor at the level of the incoming goods inspection. Because both compounds are inhomogeneously distributed between testa and embryo, separate quantitation in the two parts of the seeds is required. The second part of the investigation was focused on cocoa samples with a coconut-like note. Application of cAEDA revealed coconut-like smelling compounds δ-octalactone, δ-2-octenolactone, γ- nonalactone, γ-decalactone, δ-decalactone and δ-2-decenolactones as potential causative odorants. Quantitation of these six compounds and calculation of OAVs suggested δ-2-decenolactone as the crucial compound. Chiral analysis showed the presence of pure (R)-δ-2-decenolactone, commonly referred to as massoia lactone. Its key role for the coconut note was finally demonstrated in a spiking experiment: the addition of (R)-δ-2-decenolactone to the reference cocoa in an amount corresponding to the concentration difference between the two samples was able to provoke a coconut note in an intensity comparable to the one in the atypically smelling cocoa. To avoid an undesired coconut note caused by (R)-δ-2-decenolactone in the final products, the chocolate industry may consider its odor threshold value, that is 100 μg/kg, as a potential limit for the acceptance of fermented cocoa in the incoming goods inspection. Caterina's thesis is publication-based and includes the following three papers:     

Identification of the aroma components of acerola (Malphigia glabra L.): free and bound flavour compounds

Free and glycosidically-bound flavour compounds of acerola fruit were isolated and identified by GC and GC–MS analysis. Among the 46 compounds identified in the volatile fraction, the alcohols (3-methyl-but-3-en-1-ol, 3-methyl-butan-1-ol and 2-methyl-butan-1-ol) were predominant. Two other classes, aromatic compounds and esters, can participate in the fruity and fresh aroma of acerola. Among the 42 aglycones identified for the first time in this fruit, aliphatic alcohols and norisoprenoids were the main components. The latter were present in free form and only in traces. The hydrolysis of these aglycones could increase the fruity aroma of acerola. Four glucosides and one rutinoside were charaterized by GC–EIMS of their TFA derivatives.     

Volatile aroma constituents of gukhwa (Chrysanthemum morifolium R.)

The aroma composition of gukhwa (Chrysanthemum morifolium R.) was investigated. The volatile flavor compounds were extracted by steam distillation method. The yield of gukhwa essential oil (EO) from gukhwa flowers was 0.1%(w/w), and its color was the light green. Forty-five volatile flavor compounds making up 96.81% of the total volatile composition from the distilled oil were tentatively characterized. It contained 25 hydrocarbons with sesquiterpene hydrocarbon predominating, 7 alcohols, 3 ketones, 3 acids, 2 esters, 3 aldehydes, and 2 ethers. Chrysanthenyl acetate (43.74%) was the most abundant aroma component, and verbenol (27.85%) was also remarkable. The major functional groups of gukhwa EO were terpene ester and alcohol.     

Retracted: Temperature affects flavour intensity and quality of aroma in fresh basil (Ocimum basilicum L.) leaves

Retraction: The following article from the Journal of the Science of Food and Agriculture , ‘Temperature affects flavour intensity and quality of aroma in fresh basil (Ocimum basilicum L.) leaves’ by Xianmin Chang, Peter G Alderson, Tracey A Hollowood, Louise Hewson, and Charles J Wright, published online on 19 October 2005 in Wiley InterScience (www.interscience.wiley.com), has been retracted by agreement between the authors, the journal Editor in Chief, David S. Reid and John Wiley & Sons, Ltd. The retraction has been agreed due to overlap between this article and the following article published in the The Journal of Horticultural Science & Biotechnology ; ‘Effect of temperature integration on the growth and volatile oil content of Basil (Ocimum basilicum L.)’ by Xianmin Chang, Peter G Alderson and Charles J Wright. Volume 80 Issue 5, 2005, pages 593 – 598     

Chemical and aroma volatile compositions of date palm (Phoenix dactylifera L.) fruits at three maturation stages

The effect of maturity stage on the physicochemical composition and volatile components of date palm fruits (Phoenix dactylifera L.) was investigated at three different stages. Total sugars, pH, proteins and ash increased up to the full-ripe stage of all date types. On the contrary, weight, moisture and total lipids decreased across the same period. Pearson’s test established significant differences (p < 0.05) between the different cultivars at each stage for all the parameters. Furthermore, multivariate tests show that the composition and the variation of the chemical compositions mainly depended on the cultivar kind. Eighty volatile compounds were identified during the maturation stages, 43 of them were newly identified in Tunisian date fruits. The profiles of volatile compounds seem to be similar for Degla and Horra varieties. Results from this work revealed essential information about the richness of littoral cultivars in many nutrients and the possibility of their uses as a functional food ingredient.     

Antioxidant property of aroma extract isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry]

Aroma extract from dried clove buds [Syzygium aromaticum (L.) Merr. et Perry] was obtained by using steam-distillation under mild conditions (55°C and 95 mm Hg). The antioxidant property of the aroma extract was evaluated in two different assays. The aroma extract isolated from clove buds inhibited the oxidation of hexanal for 30 days at a level of 50 μg/ml. Clove bud extract inhibited malonaldehyde formation from cod liver oil by 93% at the 160 μg/ml level. Twenty-two compounds were identified in the extracts of clove buds by gas chromatography and gas chromatography/mass spectrometry. The major aroma constituents of clove buds were eugenol (24.371 mg/g) and eugenyl acetate (2.354 mg/g). Eugenol, eugenyl acetate, and benzyl alcohol inhibited the oxidation of hexanal by 99, 99, and 82%, respectively, for a period of 30 days at 500 μg/ml. Eugenol, eugenyl acetate, and benzyl alcohol inhibited malonaldehyde formation from cod liver oil by 88, 79, and 63%, respectively, at 160 μg/ml. The antioxidant activity of clove bud extract and its major aroma components, eugenol and eugenyl acetate, were comparable to that of the natural antioxidant, α-tocopherol (vitamin E).     

Chemical composition of ripe fruits of Rubus chamaemorus L. grown in different habitats

BACKGROUND: Cloudberry (Rubus chamaemorus L.) is one of the most valuable berry‐producing plants because of its nutritional properties. The chemical composition and crop yield of ripe fruits of cloudberry grown wild in 10 habitats in northern Finland was analysed over two consecutive summers. For comparison, two clones of cultivated cloudberries were studied as well. RESULTS: The concentrations of citric and malic acids, α‐tocopherol, anthocyanins and β‐carotene had notable variations between habitats. In particularly, cloudberries grown on open habitats had higher content of citric acid and less α‐tocopherol compared to those grown on shaded sites. In a colder and rainy summer the content of anthocyanins and the unsaturation level of fatty acids were significantly higher than in a warmer and drier summer. Crop yields were higher in the warmer summer, except in open sites where yields were quite equal. CONCLUSION: Cloudberries grown in open habitats showed notable differences in chemical composition when compared to those grown on shaded sites. Results suggest that the amount of sunlight and temperature levels could be the main factors affecting crop yield and chemical composition of cloudberry. In addition, the amount of rainfall may have an effect on anthocyanin concentrations. Copyright © 2011 Society of Chemical Industry     

The influence of skin contact during alcoholic fermentation on the aroma composition of Ribolla Gialla and Malvasia Istriana Vitis vinifera (L.) grape wines

Grapes from the Vitis vinifera (L.) varieties Ribolla Gialla and Malvasia Istriana were subjected to two skin contact procedures: pomace maceration and whole berry maceration during alcoholic fermentation. Wine free volatile compounds were determined using two extraction techniques coupled to GC; odour activity values were calculated and compared to control wines without skin contact. The highest concentrations of esters and relative fruity impacts were determined in the control wines for both varieties. Pomace maceration was found to be an effective procedure for the extraction of varietal aroma compounds like terpenes, but only in the Malvasia Istriana was their higher impact on floral odour determined. Pomace maceration resulted in higher total phenol and methanol content. Whole berry maceration was less efficient in terpene extraction, and its impact on general wine composition was not so radical. Control wines were chosen as preferred wines for odour and overall impression.     

The flavour of cape gooseberry (Physalis peruviana L.)

European Food Research and Technology - The volatile constituents of cape gooseberry (Physalis peruviana L.) were characterized using liquid/liquid extraction and fractionation of the flavour...     

The perfume of carabao mangoes (Mangifera indica L.)

A solvent extract of the pulp of Carabao mangoes (Mangifera indica) as well as the emanation of the intact fruit by SPME were investigated. The profile of the pulp is based on terpinolene, fatty acids, 2,5-dimethyl-4-hydroxy-3[2H]-furanone and its methyl ether. The SPME profile is characterized by monoterpenes, ethyl esters and by pairs of unusual unsaturated fatty acid esters: ethyl and methyl (Z)-5-octenoates, ethyl and methyl (Z)-4-decenoates and ethyl and methyl (Z,Z)-4,7-decadienoates. Synthetic samples of the new esters have been prepared for structure confirmation. The typical smell of tropical fruits is associated with 2-propanethiol.