Showing papers in "Flavour and Fragrance Journal in 2019"

Interspecific variation, antioxidant and allelopathic activity of the essential oil from three Launaea species growing naturally in heterogeneous habitats in Egypt

Abstract: Essential oils (EOs) from the aerial parts of three Launaea species collected from two different habitats were extracted [Launaea mucronata collected from coastal desert (LMC) and from inland desert (LMD), Launaea nudicaulis collected from coastal desert (LNC) and from inland desert (LND), Launaea spinosa (LS)]. The EOs were analysed by gas chromatography mass spectrometry (GC‐MS) and tested for antioxidant activity as well for allelopathic activity against purslane. A total of 117 compounds were identified from all samples, including 64 from LS, 50 from LMC, 39 from LMD, 24 from LNC, and 20 from LND, representing 100% of the total oil mass. The oxygenated sesquiterpenes were the major compounds of the EOs from LS, LMC, LMD, LNC, and LND, representing 62.73, 61.02, 58.35, 43.22, and 48.33%, respectively, whereas the monoterpene hydrocarbons were minor compounds in all samples. α‐Acorenol (31.42%), trans‐longipinocarveol (12.04%), and γ‐eudesmol (6.31%) represented the major compounds of the EO from LS, whereas hexahydrofarnesyl acetone and n‐heneicosane represented the major compounds from LMC, LMD, LNC, and LND. Correlations between the EOs of the five samples were studied via principal component analysis and agglomerative hierarchical clustering, based on the chemical composition of the EOs. There was a significant variation between Launaea species regarding both the quality and the quantity of EO composition, whereas no significant difference was observed based on the habitats (coastal and inland deserts). The EOs of the five Launaea samples exhibited meaningful antioxidant activities, as follows: LND > LNC > LMD > LMC > LS. Moreover, the EOs of the five Lanaea samples exhibited significant allelopathic activity against purslane weed in a concentration‐dependent manner. LMD and LMC showed the highest effect, with germination inhibition of 96.1 and 87.9% at 250 μL L⁻¹, and radicle growth inhibition of 92.6 and 89.7%, but LS was the least effective extract. Our results showed that the variation in the quality and quantity of EO composition is mainly species specific, with a slight correlation with habitats.

Combination of 13C and 2H SNIF‐NMR isotopic fingerprints of vanillin to control its precursors

Abstract: Synthetic vanillin is the flavouring most used in agro‐food industries, but more and more frequently consumers are now turning to natural origin. Vanilla planifolia (Andrews) is the most commercialized species of pods in the world and is mainly produced in Madagascar. However, periodically the production of V. planifolia suffers from poor climatic conditions, with the resulting degradation of both the quality and the quantity of the pods. Consequently, the price of vanilla pods rose to record in 2017 and the risk of fraud has increased in response. Analytical methods based on isotopic compositions have already proven their ability to ensure the authenticity of natural vanillin. In 2006, ²H SNIF‐NMR (site‐specific natural isotopic fractionation by nuclear magnetic resonance) was approved as official method by the Association of Official Analytical Chemists (AOAC 2006.05). However, this method is time consuming and the extraction of 1 g is cumbersome for the finished products. The information brought by combined ²H and ¹³C SNIF‐NMR profiles was compared using chemometric tools to determine the best routine tool to improve both the global analysis time and the potential of detection. As a result of this work the ability of the SNIF‐NMR method to verify the authenticity of vanillin has been improved, in particular by providing the first means to discern the geographical origin of vanilla pods. Furthermore, ¹³C NMR using pulse sequences such as INEPT (insensitive nuclei enhanced by polarization transfer) offers the possibility to improve the sensitivity of the analysis, with a reduced quantity of product (less than 50 mg) and a shorter analysis time, which will facilitate the study of the finished matrices as well as clearly discriminating the origins of the vanilla flavourings.

Essential oils of Moldavian Thymus species: Chemical composition, antioxidant, anti‐Aspergillus and antigenotoxic activities

Abstract: Genus Thymus L. comprises about 250 species of perennial, aromatic and medicinal plants and subshrubs native to Europe, North Africa and Asia.1 They are widely used as culinary herbs, flavouring and food preservative agents, and they have numerous significant applications in pharmaceutical, food and cosmetic industries, and also in perfumery. Various biological properties have been reported for thyme species, such as: antioxidant, antimicrobial, antiinflammatory, antinociceptive, spasmolytic, expectorant, or antitumor.1–3 The Received: 29 August 2018 | Revised: 19 November 2018 | Accepted: 17 November 2018 DOI: 10.1002/ffj.3490

Characterization of key aroma compounds in Laobaigan Chinese Baijiu by GC×GC‐TOF/MS and means of molecular sensory science

Abstract: Laobaigan (LBG) Baijiu is recognized as one of the famous Chinese liquors due to its unique flavor characteristics. However, its key aroma‐active volatiles are still unknown. In this study, 414 volatile chemicals in the LBG Baijiu were initially detected by comprehensive two‐dimensional gas chromatography‐time‐of‐flight mass spectrometry (GC×GC‐TOF/MS). Then, 52 of them were determined by sample dilution analysis (SDA) for screen of aroma‐active compounds. Based on their odor–activity values (OAVs) that were determined by the external standard method performed on the GC×GC‐TOF/MS, 32 volatile compounds were further recognized as important odorants, which were reconstituted to simulate and validate the aroma profile of the LBG Baijiu. Moreover, omission experiments were conducted to corroborate the importance of key odorants. As a result, nine aroma compounds were finally confirmed as the key aroma‐active compounds of the LBG Baijiu.

Authentication of the geographical origin of patchouli oil using front‐face fluorescence spectroscopy and chemometric analysis

Abstract: Increasing consumer awareness of the authenticity of products has led to a demand for rapid measurement methods to support the traceability of high‐value commodities. In this research, a front‐face method was used to obtain fluorescence excitation–emission matrix fingerprints of patchouli oil samples from different geographical origins in Indonesia. Principal component analysis (PCA) was then used to explore the excitation–emission matrix (EEM) data structure of the samples, and 3D eigenvector value thresholding was used to discriminate important variables. It was found that there were five important EEM regions representing the sample variation. A decision‐tree model with a subset of two important regions, i.e. regions 1 and 3, was then developed for the classification of patchouli oils from different Indonesian islands. These results show that front‐face fluorescence spectroscopy has the potential to be used as a supporting tool for the discrimination of the geographical origin of patchouli oils.

Combined impacts of zein coating enriched with methanolic and ethanolic extracts of sour orange peel and vacuum packing on the shelf life of refrigerated rainbow trout

Abstract: In this study, the antioxidant potency of aqueous ethanolic and methanolic extracts of sour orange peel was assessed. The antioxidant and antibacterial characteristics of zein coating enriched with these extracts were then evaluated for refrigerated fish stored with vacuum packing (VP). The antioxidant activities of the hydroalcoholic extract were more potent than those of the methanolic extract. The total viable counts of Enterobacteriaceae, Pseudomonas spp., and psychrotrophic bacteria in all of the samples were significantly decreased, compared with the control, for the storage period. Thiobarbituric acid reactive substances, peroxide, total volatile basic nitrogen, and free fatty acids were significantly lower in all treated samples, compared with the control. In the sensorial assessment, the coated samples enriched with different concentrations of extracts were mostly preferred by the sensory analyst. In combination, the coating layers increased the shelf life of fish for 12 days. Edible coatings are significant protective agents for perishable foods such as seafood. Longer shelf lives are feasible with different processing methods, such as edible coatings and plant extracts, and with suitable combinations of these agents. The enrichment of zein coatings by essential oils or extracts can improve the sensory attributes (such as flavour, taste, and colour), as well as antioxidant and antimicrobial characteristics.

Effect of Harvesting Time on Volatile Compounds Composition of Bergamot (Citrus × Bergamia) Essential Oil

Abstract: Bergamot (Citrus × bergamia) is mainly cultivated in Calabria area (Italy) for its essential oil that is widely used in cosmetics, food and medicine. The harvest season (November to February) affects the quality of essential oil, consequently the aim of our study was to evaluate the composition of volatile fractions at different harvesting stages. Two different cultivars, Femminello and Fantastico, were collected in November, December and January and their volatile compounds composition was determined by SPME GC/MS. Fourty‐two compounds were identified. Monoterpenes were the preponderant group; limonene was the most representative compound with similar concentrations in the varieties and at the three harvesting times. β‐Ocimene, β‐mircene and α‐terpinene showed higher concentration in Femminello than Fantastico, while trans‐α‐bergamotene, α‐pinene and citronellal were mostly concentrated in Fantastico. The concentration of β‐pinene in Fantastico and Femminello was higher in December and January, respectively, and γ‐terpinene concentration was higher in Femminello in November and January and in Fantastico in December. Linalool was the most preponderant monoterpene alcohol with a significantly higher concentration in Femminello than in Fantastico, but without significant differences during ripening. cis‐γ‐Bisabolene was the most preponderant sesquiterpene; it was more concentrated in Fantastico than in Femminello and showed a significantly higher concentration in December and January than in November. Linalyl and neryl acetate were the most abundant esters, with a significantly higher concentration in Fantastico. Fantastico seems to be the variety that produces higher volatile organic compounds in essential oil; moreover, the volatile compound concentration was higher at the second and third harvest time.

Continuous production of eugenol esters using enzymatic packed‐bed microreactors and an evaluation of the products as antifungal agents

Abstract: The enzymatic synthesis of biologically active compounds is receiving increasing interest from academic and industrial researchers. Herein, we report on the continuous‐flow enzymatic production of eugenol esters with packed‐bed microreactors prepared with the Novozym 435 and Lipozyme RM IM lipases. After optimization of the independent process variables, namely temperature (68 °C), flow rate (8 μL min⁻¹), and eugenol/isobutyric anhydride molar ratio (1 : 5) by means of experimental design methodologies, the unprecedented continuous‐flow production of eugenyl isobutyrate has been achieved with steady‐state conversions of 77 and 70%, using packed‐bed microreactors prepared with Novozym 435 and Lipozyme RM IM, respectively. With acetic anhydride as the acylating agent, the same reactors, under the same conditions, afforded eugenyl acetate with steady‐state conversions of 82% (Novozym 435) and 90% (Lipozyme RM IM). The two ester products have been tested against phytopathogenic and dermatophytic fungi, demonstrating interesting action against dermatophytic fungi. The reported results demonstrated the suitability of the enzymatic packed‐bed microreactors as a sustainable and scalable technology for the solvent‐free continuous‐flow production of biologically active esters of eugenol.

Oxygen heterocyclic compound screening in Citrus essential oils by linear retention index approach applied to liquid chromatography coupled to photodiode array detector

Abstract: To date, liquid chromatography coupled to a photodiode array (PDA) detector is the main technique employed to analyse furocoumarins (FCs) in essential oils. This type of detection may lead to poor performance because of the low sensitivity and selectivity of PDA detection. In this work, the linear retention index (LRI) was used in combination with a UV‐Vis library for the identification of 35 oxygen heterocyclic compounds in Citrus essential oils, making it possible to distinguish compounds with very similar spectra. As opposed to retention time, which can significantly change with the instrument or laboratory used, LRI represents a kind of normalized relative retention time, as independent as possible from operating conditions. From a qualitative point of view, reproducibility results are provided to definitively assess the suitability of such an approach for inter‐laboratory use and for a fully automated process, even when pure and very expensive standard materials are not available, as just the LRI database and the UV‐Vis library are needed. From a quantitative point of view, calibration curves were created in pure solvent and by adding standard compounds to several blank matrices, with the aim of evaluating differences, overcoming matrix effects, achieving the correct limits of quantification, and providing the quantitative profile of real samples. The LRI system is not listed in the Commission Decision 2002/657/EC as criteria for the Full Scan UV‐Vis detection; however, its validity and applicability are here investigated and proposed for future applications, in combination with the UV‐Vis library.

Chemical disparity in the oil from leaves of Cinnamomum zeylanicum Blume

Abstract: The hydrodistilled essential oil obtained from leaves of Cinnamomum zeylanicum Blume (Lauraceae) collected throughout the year was examined using gas chromatography fitted with flame ionization detector (GC‐FID) and gas chromatography connected with mass spectrometry (GC‐MS). The variation in essential oil yield was found to be in the range of 1.1–1.4% (w/w). Between 28 and 40 components, representing 97.92 ± 0.15% of the total oil, were identified. The chief compound was identified as eugenol, varying from 60.24 ± 0.42 to 89.82 ± 0.55%. The other constituents were eugenyl acetate (ranging from 0.10 ± 0.01 to 19.87 ± 0.52%), α‐phellandrene (ranging from 0.76 ± 0.04 to 6.23 ± 0.13%), benzyl benzoate (ranging from 0.91 ± 0.05 to 5.03 ± 0.20%), linalool (ranging from 1.11 ± 0.04 to 3.25 ± 0.08%), and β‐caryophyllene (ranging from 0.50 ± 0.01 to 2.92 ± 0.10%). The essential oils collected throughout the year were found to be rich in phenyl derivative constituents (88.49 ± 0.97%). The biosynthesis and conversion of eugenyl acetate to eugenol appeared as the leaves of C. zeylanicum reached maturity. It was noticed that when leaves were immature, in July and August during the full rainy season, the content of eugenyl acetate was found to be highest, as compared with mature leaves in the other months, with the exception of February (flowering season).

Effect of boiling time on the contents of flavor and taste in Lentinus edodes.

Abstract: The changes of flavor components during boiling in Lentinus edodes were studied by high‐performance liquid chromatography and gas chromatography‐mass spectrometry in this article. Results showed that nonvolatile flavor components in L. edodes gradually transferred into the soup during boiling. Contents of nonvolatile flavor substances in the soup increased significantly (p < .05) compared with the preboiling period (15 minutes) and gradually maintained a balanced situation with the boiling time extended. During boiling, content of alcohols gradually reduced, especially the content of 1‐octen‐3‐ol, which is a typical flavor component in L. edoedes. The contents of sulfur compounds, aldehydes, and hydrocarbons increased first and finally decreased gradually with the boiling time extended. Therefore, the changes of flavor components in the soup almost maintained a balanced situation with the boiling time from 30 to 60 minutes. The results of this article could provide a theoretical basis for the changes of flavor compounds in L. edodes during boiling.

Designing nanoporosity in a swollen polymer for the controlled release of a highly volatile fragrance

Abstract: Controlling the fragrance release profile, especially the highly volatile top note, can prolong the desired scent of the fragrance. Here, the porosity of a swollen cross‐linked polyurethane acrylate (PUA) polymer, which is tuned by the length of a modulator, can influence the evaporation rate of the top note. In particular, the evaporation rate of benzyl acetate (BA), a common top note, is reduced by a factor of 6.5 (from 134 to 17 mg m–² min–¹) when BA is released from the best‐performing PUA against a reservoir of BA. The average diameter of an opening in the fragrance‐loaded PUA is ~6 nm, as determined by the thermoporosimetry approach. Such a pore size can effectively control the evaporation rate of BA, as predicted by the theoretical model, which reveals that a pore diameter of <16 nm is required. Computational modelling reveals the optimal chain length for a modulator used for the sustained released of fragrance, confirming the experimental data. Finally, BA continues to be released from the PUA matrix for a prolonged period, even after 3 months, whereas the same quantity of BA would completely evaporate after 1 week in the absence of PUA matrix. Approximately 50wt% of BA remains after 60 days, making it one of the best techniques in sustaining the release of a top note.