HS-SPME coupled to GC/MS for quality control of Juniperus communis L. berries used for gin aromatization

HS-SPME coupled to GC/MS was applied to the analysis of the volatile fraction of Juniperus communis L. berries, which are the principal ingredient used for gin aromatization. Seventy seven compounds were identified by comparison with reference compounds or tentatively identified by comparing their mass spectra and retention index with those reported in mass spectra libraries and literature, respectively. Seventy four were detected by SPME and sixty eight were detected by solvent distillation extraction (SDE). These were mainly mono- and sesquiterpenic compounds that represented more than the 80% of the gin’s volatile composition. A high percent content was due to monoterpenoids, whose analysis could be important for the assessment of sensory quality control of juniper due to their impact on gin aroma. The main monoterpenoids detected in the headspace of the juniper berries from two periods of collection were terpinen-4-ol, p-cymene, β-myrcene, γ-terpinene, α-pinene and limonene. These represented more than the 70% of the sample’s volatile fraction. The proposed SPME method required short times and the low cost of analysis and enabled to detect a number of compounds comparable with SDE or much higher than the number of compounds reported by other extraction techniques. The results suggested the suitability of this technique for the assessment of the volatile composition of juniper berries intended for gin flavouring.     

Effect of different technological processes on the chemical composition of myrtle (<Emphasis Type="Italic">Myrtus communis</Emphasis> L.) alcoholic extracts

Several technological processes were applied to improve the extraction efficiency in the production of myrtle (Myrtus communis L.) liqueur. The variations in the chemical composition of myrtle hydroalcoholic extracts were monitored in a laboratory scale for 40 days after the application of: double dose of berries; ultrasonic extraction; enzymes, to improve either the color or aroma extraction; and atmosphere saturated with nitrogen to improve the stability against oxidative degradations during extraction. Moreover, freezing at −20 °C was applied to myrtle berries as a technological strategy to prolong the use of berries, and macerates were obtained after 4, 8, and 12 months. Chemical investigation of macerates was performed using different analytical methods such as GC and GC-MS for the volatile compounds, HPLC-PDA for free anthocyanins, and spectrophotometric analysis for CIE L*a*b* coordinates and total anthocyanins. Dry matter and pH were also monitored during maceration. Among the different technological processes, the nitrogen-modified atmosphere was the most suitable technique to be applied in industrial scale. An industrial trial was applied with this process and alcoholic extracts and liqueurs have been obtained. The liqueur maintained a higher amount of anthocyanins, better CIE L*a*b* parameters and superior organoleptic characteristics compared to the traditional storage.     

Comparison of HS-SPME with hydrodistillation and SFE for the analysis of the volatile compounds of Zisu and Baisu,two varietal species of Perilla frutescens of Chinese origin

Content and composition of the volatiles of Baisu and Zisu, two varieties of Perilla frutescens, obtained by SFE, HS-SPME, and hydrodistillation, were compared. A total of 64 compounds were identified by GC/MS. Perillaldehyde (21.9–58.1%) and perilla ketone (54.5–83.5%) were the main volatile components of Zisu and Baisu, respectively. They might be partly responsible for the aroma and taste of perilla. The abundance of perilla ketone indicates that it is not safe to use Baisu as vegetable, and Baisu should not be used as substitute for Zisu. SFE extracted oil with high yield, and extracted some high molecular-weight compounds that did not contribute to the aroma. The HS-SPME was simple and sensitive for the analysis of volatile compounds of fresh perilla. The results showed that the drying process influenced the volatile components of perilla.     

Direct enantiomeric analysis of Mentha essential oils

A rapid and fully automated screening of chiral compounds in essential oils, aimed to the selection of natural sources of pure enantiomers of limonene and carvone, is performed by using on-line coupled reversed phase liquid chromatography with gas chromatography and mass spectrometry (RPLC–GC–MS). Essential oils obtained from Mentha spicata and Mentha piperita were analysed by direct injection into RPLC. The reported procedure includes fractionation and clean-up in RPLC, selection of the fraction to be transferred from RPLC to GC, trapping and concentration of the target compounds in the interface, thermal desorption and, finally, enantiomeric resolution and identification of chiral compounds by GC–MS. The presence of (S)-limonene and (R)-carvone as the unique enantiomeric forms existing for both compounds could be unambiguously established by transferring different volume fractions from RPLC to GC. Data obtained demonstrate high separation efficiency and well tunable selectivity in the on-line coupled RPLC–GC–MS analysis of chiral compounds.     

First mass spectrometry metabolic fingerprinting of bacterial metabolism in a model cheese

Metabolic fingerprinting is an untargeted approach which has not yet been undertaken to investigate cheese. This study is a proof of concept, concerning the ability of mass spectrometry (MS) metabolic fingerprinting to investigate modifications induced by bacterial metabolism in cheese over time. An ultrafiltrated milk concentrate was used to manufacture model cheeses inoculated with Lactococcus lactis LD61. Metabolic fingerprints were acquired after 0, 8 and 48 h from two different fractions of the metabolome: the water-soluble fraction using liquid chromatography–high resolution-MS and a volatile fraction using gas chromatography–MS. Metabolic fingerprints differed significantly over time. Forty-five metabolites were identified, including well-known cheese metabolites, such as 12 amino acids and 25 volatile metabolites, and less studied ones, such as four vitamins, uric acid, creatine and l-carnitine. These results showed the relevance of cheese MS fingerprinting to generate new findings and to detect even slight differences between two conditions.     

Melissopalynological origin determination and volatile composition analysis of Corsican “chestnut grove” honeys

Fifty Corsican “chestnut grove” honeys were certified by melissopalynological analysis. Castanea sativa was strongly overrepresented and was accompanied mainly by Rubus sp., Quercus ilex, Anthyllis hermanniae, Myrtus communis, Genista sp., Erica arborea, Cistus creticus, and Fraxinus ornus. Headspace solid-phase microextraction was performed to investigate the volatile composition of Corsican chestnut catkins and chestnut grove honeys. The main compounds of the chestnut catkins were acetophenone (21.5%), methyl salicylate (13.4%), nonanal (10.9%), and linalool (7.5%), whereas the major constituents of the honeys were 2-aminoacetophenone (11.4%), benzaldehyde (10.8%), acetophenone (7.0%), nonanoic acid (5.9%), octanoic acid (5.0%), and 3-furaldehyde (4.9%). By entering the aromatic intensity, the relative frequency of C. sativa, Rubus sp., and A. hermanniae pollens, and the physicochemical parameters as discriminate variables, principal component analysis (PCA) and cluster analysis (CA) showed that the distribution of Corsican “chestnut grove” honeys correlates with climatic events and/or honeybee foraging behaviours.     

Application of Central Composite Design to evaluate the antilisterial activity of hydro-alcohol berry extract of Myrtus communis L.

The antimicrobial activity of the hydro-alcohol extract of Myrtus communis L. (ME) berries was investigated against six Listeria monocytogenes strains (2 type strains and 4 isolates). Sub-lethal ME concentrations reduced L. monocytogenes counts by at least 2 log cycles. A Central Composite Design was used to investigate the combined effects of sub-lethal concentrations of ME (0.039–0.195 mL/100 mL), NaCl (0–2.0 g/100 mL) and pH (5.0–7.0) on strains growth. ME affected growth parameters, generally extending lag phase length and reducing maximum growth, sometimes with interactive effects with pH. The highest ME concentrations (0.117–0.195 mL/100 mL) combined with the lowest pH values (5.0–6.0) strongly reduced or even inhibited strains growth.     

Essential oil composition of Pterospartum tridentatum grown in Portugal

The essential oils, isolated by hydrodistillation and distillation-extraction, from the aerial parts of different populations of Pterospartum tridentatum collected during the flowering phase, at different locations in Portugal, were analysed by GC and GC–MS. All the P. tridentatum populations studied afforded a yellowish oil in a yield <0.05% (v/w). cis-Theaspirane (2–14%), trans-theaspirane (2–17%) and octen-3-ol (2–37%) were, in variable amounts, the dominant components of the oils. Cluster analysis of the essential oil compositions from the nine populations studied, confirmed a major chemical variability.     

Influence of deficit irrigation and kaolin particle film on grape composition and volatile compounds in Merlot grape (Vitis vinifera L.)

The effect of deficit irrigation and a kaolin-based, foliar reflectant particle film (PF) on grape composition and volatile compounds in Merlot grapes was investigated over two growing seasons in semi-arid, south-western Idaho. Vines were provided with differential amounts of water based on their estimated crop evapotranspiration (ET_c) throughout berry development, and particle film was applied to half of the vines in each irrigation main plot. Free and bound volatile compounds in grapes were analyzed using stir bar sorptive extraction–gas chromatography–mass spectrometry (SBSE–GC–MS). The concentrations of free C₆ compounds (hexanal, trans-2-hexenal, and 1-hexanol) decreased, and bound terpene alcohols (nerol and geraniol) and C₁₃-norisoprenoids (β-damascenone, 3-hydroxy-β-damascenone, 1,1,6-trimethyl-1,2-dihydronaphthalene, and 3-oxo-α-ionol) increased in berries each year in response to severity of vine water stress. Concentrations of C₁₃-norisoprenoids and bound forms of nerol and geraniol were positively correlated with their concentrations in the corresponding wines. Particle film application had minimum effect on free and bound volatile composition in the grapes, and there was no interactive effect between particle film and deficit irrigation. However, particle film application enhanced the total amount of berry anthocyanins.     

Active odorants in Mouratón grapes from shoulders and tips into the bunch

The opportunity for obtaining different wines from the same variety cultivated in the same vineyard is becoming of increasing importance. This is why some wine cellars have started to assay the separation of the tips and shoulders berries of the clusters of a specific variety with this objective. In this work, the study is focused on berries of Mouratón (Vitis vinifera L.) to investigate if, in the latter stages of ripening, differences exist in the probable alcoholic degree, total acidity of the must, as well as in the aromatic composition of skin and flesh of berries coming from the tips and shoulders of the clusters. Gas chromatography coupled to mass spectrometry (GC–MS) was used to determine the aromatic composition. The obtained results showed that there was not variability for the probable alcoholic degree and total acidity between the tips and shoulders, whereas there was variability for their aromatic composition during ripening. These results are promising for those wine cellars that are considering the separation of berries from tips and shoulders of the clusters for the elaboration of different quality wines.     

Essential oil composition of Salvia miltiorrhiza flower

Hydrodistillation of the flower of seven populations of Salvia miltiorrhiza Bge. collected in different locations in China afforded a pale yellowish oil in a yield of approximately 0.2%. A total of 82 compounds were identified across all the samples, accounting for 98–100% of the total compositions of each sample. Components were mainly monoterpenes, sesquiterpenes, fatty acids and alkanes. GC and GC–MS analysis indicated that the predominant components of the essential oils are β-caryophyllene (12.2–31.7%), β-caryophyllene oxide (1.4–11.6%), α-caryophyllene (4.8–10.6%), cadinadiene (7.4–29.3%), and hexadecanoic acid (3.9–18.8%).     

Chemical variation in the essential oil ofEphedra sinica from Northeastern China

Hydro-distillated volatile oils of Ephedra sinica Stapf. from six populations of Inner Mongolia in Northeastern China were analyzed by using GC/MS. Ninety-nine compounds were identified in the oils and a relatively high variation in their contents was found. The main constituents of the essential oils were α-terpineol (19.28–52.23%), p-vinylanisole (0.59–11.64%), 3-methyl-2-buten-1-ol (0–5.44%), tetramethylpyrazine (0.63–8.99%), terpine-4-ol (1.17–4.37%), α-linalool (1.62–5.15%), phytol (1.24–15.73%), γ-eudesmol (0–7.77%), and eudesm-7(11)-en-4-ol (0.41–6.13). Six populations were divided into two chemotypes based on cluster analysis and principal component analysis (PCA); one rich in α-terpineol and p-vinylanisole, and the other rich in phytol, γ-eudesmol, and eudesm-7(11)-en-4-ol.     

Comparative analysis of clary sage (S. sclarea L.) oil volatiles by GC–FTIR and GC–MS

The comparative analysis of volatiles in essential oil by gas chromatography–Fourier transform infrared spectrometry (GC–FTIR) and gas chromatography–mass spectrometry (GC–MS) are investigated using a DB-wax capillary column. This technique is applied to allelochemicals present in volatiles. The identification analysis of volatile components in four kinds of clary sage (Salvia sclarea L.) oil is described. The GC–FTIR information obtained is complementary to the information obtained from GC–MS. With the IR subtractive spectrum technique, the GC overlap peaks can be resolved without further separate step on the other column of different polarity. Combined with GC–FTIR, GC–MS techniques, and linear retention indices (RI) of the volatile compounds, the reliability of qualitative analysis is greatly enhanced.     

Antioxidant capacity and vasodilatory properties of Mediterranean food: The case of Cannonau wine,myrtle berries liqueur and strawberry-tree honey

The aim of this work was to use different assays to evaluate the antioxidant and vasodilatory properties of three typical food products from the Mediterranean area and to correlate these activities with their phenolic content. For this purpose, red wines Cannonau, liqueurs obtained by cold maceration of myrtle (Myrtus communis L.) berries and bitter honeys obtained from strawberry-tree flowers (Arbutus unedo L.) were analysed. The total phenolic (TP) content was measured spectrophotometrically with a modified Folin–Ciocalteau method and phenolic compounds were identified and dosed by HPLC-DAD and LC-MS/MS. Antioxidant activities were evaluated with DPPH, FRAP and ABTS assays and the in vitro vasodilatory effects were assessed using norepinephrine precontracted rat aortic rings. Cannonau wines and myrtle liqueurs showed high levels of TP (1978 ± 279 and 1741 ± 150 mg GAE/L, respectively), linearly correlated to the results of FRAP, ABTS, and DPPH assays. Their maximal vasodilatory activity was 61.7 ± 4.1% and 53.0 ± 3.0%, respectively. Although strawberry-tree honey contained relatively high levels of phenolic compounds (922 ± 38 mg GAE/kg), it did not induce vasodilation, even at the highest dose tested (0.206 g/L). These results indicate that foods with high levels of phenolic compounds should be studied using several different biological assays before being recommended to the general public as functional foods.     

Evaluation of the volatile profile of 33 Pyrus ussuriensis cultivars by HS-SPME with GC–MS

Evaluation of the volatile compounds in fruit provides useful information for plant breeding for improved fruit aroma. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS) was used to assess the volatile profile of 33 cultivars of the Chinese pear Pyrus ussuriensis. In all, 108 volatile compounds were identified and there were significant differences in the composition and concentration of volatiles among cultivars. On the basis of principal components analysis (PCA), the cultivars could be divided into four groups: Group 1 contained Reli, Jinxiang, Hongbalixiang, Baibalixiang and Fuwuxiang, cultivars with a high concentration of esters and a low concentration of hydrocarbons. Group 2 contained Qiuxiang, Fuanjianba, Longxiang, Guanhongxiao, Shanli24 and Wuxiangli, cultivars with high concentrations of hydrocarbons and low concentrations of esters. Group 3 contained Shatangli and Manyuanxiang, cultivars with high concentrations of aldehydes. Group 4 contained the other 25 cultivars.     

Volatile compounds of copoazú (Theobroma grandiflorum Schumann) fruit

Volatile compounds were isolated from copoazú (Theobroma grandiflorum Schumann) fruit by liquid–liquid extraction at two different pH values of 3.3 (natural) and 7. The volatile extracts were analyzed by capillary GC–FID and GC–MS. Among the 56 compounds identified at two pH values, many of them were only present in the lower pH extract, confirming the presence of bound compounds in copoazú. Ethyl butanoate, ethyl hexanoate and linalool were the major constituents found in copoazú fruit.     

Volatile composition of hybrids Citrus juices by headspace solid-phase micro extraction/gas chromatography/mass spectrometry

The volatile compounds of Citrus juices have been extracted by headspace solid-phase microextraction (HS-SPME) and analysed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). This work deals with the analysis of 65 cross pollinated hybrid fruits and their parents: mandarin (Citrus reticulata Blanco var. Willow Leaf) and clementine (Citrus reticulata × Citrus sinensis var. Commune). Among the 44 components identified which accounted for 90.2 to 99.8% of the volatile fraction, limonene (56.8–93.3%) and γ-terpinene (0.1–36.4%) were the major components in all samples. The clementine juice was characterised by the pre-eminence of limonene (90.0%) and a minor amount of γ-terpinene (1.2%) while the mandarin juice exhibited high amount of limonene (66.3%) and γ-terpinene (21.1%). All hybrid juices showed qualitatively similar composition but differing in the quantitative profile of the couple limonene/γ-terpinene. The principal component analysis (PCA) and the discriminant analysis indicated that hybrids samples were symmetrically distributed around the both parents. If some studies were found in the literature about mandarin juice, to our knowledge, this work is the first study on the volatile compounds of clementine juice and a large amount of hybrids.     

Examination of freshness degradation of sourdough bread made with kefir through monitoring the aroma volatile composition during storage

The aroma volatile compositions of sourdough breads containing kefir grains were monitored by SPME GC–MS analysis during a 5-day storage. Breads were made with (A) 20% w/w and (B) 10% w/w (on flour basis) kefir sourdough, and were compared with breads made with 20% w/w commercial sourdough (C) and sourdough prepared in the laboratory (D) without addition of starter culture. A dramatic decrease of volatiles was observed during storage for all samples, but the kefir sourdough breads (A and B) exhibited more complex profiles of volatiles with lower loss rates during storage. Differences in the percentages of esters on total volatiles were also observed (6.2%, 5.0%, 2.8% and 2% in the case of breads A, B, C, and D, respectively). The customer oriented sensory evaluation revealed significant differences among the tested samples, with best results scored in the case of bread A in all days of storage, agreeing with the analytical data.     

Buckwheat honeys: Screening of composition and properties

The quality of 10 buckwheat honeys, collected from Italian and est European beekeepers declaring to produce monofloral honey, were evaluated by means of their pollen, physicochemical, phenolic and volatile composition data. The results of the traditional analyses and in particular electrical conductivity, optical rotation, pH and sugar composition revealed some poorly pure samples that could not fit in the buckwheat tipology. Honey volatiles, analysed by solid phase microextraction (SPME) and gas chromatography–mass-spectrometry (GC/MS), showed more than 100 volatile compounds, most of them present in all honey samples but with quantitative variation. Besides many furfural derivates, 3-methylbutanoic acid was the main volatile compound found in most of honeys. Also the presence of 2- and 3-methylbutanal and pheynalcetaldehyde confirmed the typical buckwheat aroma of some studied samples, corroborating physicochemical data. The HPLC phenolic profile was similar across the samples and p-hydroxybenzoic and p-coumaric acids proved to be the main components.     

Chemical composition and antioxidant activities of Myrtus communis L. berries extracts

Myrtle (Myrtus communis L.) berries extracts were prepared with solvents at different polarity (water, ethanol, and ethyl acetate) and analysed using different in vitro tests in order to evaluate their antioxidant properties. Antiradical and total antioxidant activities were measured with DPPH and FRAP tests, respectively. Their ability to protect biological molecules was assessed using the cholesterol and LDL oxidation assays. In addition, phenolic compounds and unsaturated fatty acids composition was analysed by HPLC–DAD and HPLC–MS/MS. Ethanol and water extracts showed the highest amount of extracted compounds, but the highest antiradical and antioxidant activities were found in ethanol and ethyl acetate extracts. These extracts were also the ones with the highest content of phenolic compounds. In addition, our results showed a highly significant correlation between the amount of total phenols and antiradical (R² = 0.9993) or antioxidant activities (R² = 0.9985) in these extracts. HPLC–DAD and HPLC–MS analyses showed significant quantitative and qualitative differences among these three extracts. The ethyl acetate extract had the highest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu²⁺-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that because of these properties, myrtle berries could be used in dietary supplements preparations or as food additives.