Quantitative determination and characteristic flavour ofCitrus junos (yuzu) peel oil

Molecular-Sensory Decoding of the Citrus latifolia Aroma

A modified aroma extract dilution approach (AEDA), followed by the determination of flavor dilution (FD) factors, a quantitative analysis and calculation of the relative flavor activity (RFA) and odor activity values (OAVs) as well as recombination experiments were conducted to evaluate the odor- and taste-relevant components of cold-pressed Citrus latifolia peel oil. A 2-fold concentration by distillation and reanalysis, compared with the original oil, revealed relevant components. Partition of the odor-active substances into four reconstitution groups according to their respective FD factors, followed by a recombination, allowed for a better understanding of the contribution of each FD-factor group to the overall aroma. Especially α-pinene, limonene, γ-terpinene, and 7-methoxycoumarin contribute significantly to the distinct aroma profile of C. latifolia. Heptadecanal (CAS 629-90-3) was described for the first time as an odor-active substance in an enriched C. latifolia peel oil. Campherenyl acetate (CAS 18530-07-9) was identified in nature for the first time and described with a herbal, minty and citrus-like odor. The odor profile of the final recombinant mixture, containing 36 components, was similar to cold-pressed C. latifolia peel oil for most descriptors, whereas the taste profile was described as more aldehydic and citral-like.

Ethnobotany and diversity of Citrus spp. (Rutaceae) as a source of "Kem-kem" traditional medicine used among the Karo sub-ethnic in North Sumatra, Indonesia

The Karo sub-ethnic is one of five Batak sub-ethnicities in the Karo Regency, North Sumatra Province, Indonesia. They are famous for their local knowledge about the traditional use of medicinal plants to treat various diseases. The "Kem-kem" traditional medicine is one of the traditional healing practices that involve using plants passed down through generations from their ancestors. One of the plant genus group in the Rutaceae family utilized in the traditional "Kem-kem" healing practice is a citrus known as "Rimo". This study aims to document the local knowledge about the diversity of Citrus spp. as Kem-kem's herbal medicinal plant. This study was conducted from April to July 2023 in the Kabanjahe and Berastagi districts, Karo Regency, North Sumatra. Data was collected using interviews with traditional healers, herbal medicine vendors, and direct observations at traditional markets, involving a total of 8 Citrus spp. The Karo uses "Rimo" with different local names as sources of traditional medicinal ingredients in practicing "Kem-kem". There are 15 local names comprising eight species of Citrus. Four are hybrids, i.e., Citrus x aurantiifolia (Christm.) Swingle, Citrus × aurantium L, Citrus × junos Siebold ex Yu.Tanaka, and Citrus × taitensis Risso. Two of the remaining species are recognized in infraspecific rank, one variety (Citrus medica var. sarcodactylis (Hoola van Nooten) Swingle) and one form (Citrus × aurantium f. deliciosa (Ten.) M.Hiroe). They were used as material sources for Kem-kem traditional medicine to treat at least nine health problems. There are two species with six local names included in the Least Concern (LC) category, namely C. medica (Rimo Gawang, Rimo Hantuantu, Rimo Kayu), C. medica var. sarcodactylis (Rimo Kuku Harimau), and C. medica (Rimo Telur Buaya), C. maxima (Burm.) Merr. (Rimo Malem). Nine local names are included in the Not Evaluated (NE) category, namely C. × junos (Rimo Kejaren), C. × taitensis (Rimo Jungga), C. × aurantium f. deliciosa (Rimo Keling), C. × aurantium (Rimo Kersik), Citrus hystrix DC. (Rimo Mukur), C. × taitensis (Rimo Puraga), C. × aurantium (Rimo Kalele), Citrus swinglei Burkill ex Harms (Rimo Pagar), and C. x aurantiifolia (Rimo Bunga). Rimo Kejaren (C. × junos) is a species that has the most benefits.

Biological Activities and Chemical Composition of Essential Oil from Hedyosmum purpurascens (Todzia)-An Endemic Plant in Ecuador

Hedyosmum purpurascens is an endemic species found in the Andes of Ecuador and it is characterized by its pleasant smell. In this study, essential oil (EO) from H. purpurascens was obtained by the hydro-distillation method with a Clevenger-type apparatus. The identification of the chemical composition was carried out by GC-MS and GC-FID in two capillary columns, DB-5ms and HP-INNOWax. A total of 90 compounds were identified, representing more than 98% of the total chemical composition. Germacrene-D, ϒ-terpinene, α-phellandrene, sabinene, O-cymene, 1,8-cineole and α-pinene accounted for more than 59% of the EO composition. The enantioselective analysis of the EO revealed the occurrence of (+)-α-pinene as a pure enantiomer; in addition, four pairs of enantiomers were found (α-phellandrene, o-cymene, limonene and myrcene). The biological activity against microbiological strains and antioxidants and the anticholinesterase properties were also evaluated and the EO showed a moderate anticholinesterase and antioxidant effect, with an IC₅₀ value of 95.62 ± 1.03 µg/mL and a SC₅₀ value of 56.38 ± 1.96. A poor antimicrobial effect was observed for all the strains, with MIC values over 1000 µg/mL. Based on our results, the H. purpurasens EO presented remarkable antioxidant and AChE activities. Despite these promising results, further research seems essential to validate the safety of this medicinal species as a function of dose and time. Experimental studies on the mechanisms of action are essential to validate its pharmacological properties.

Sensory and Chemical Characteristic of Two Insect Species: Tenebrio molitor and Zophobas morio Larvae Affected by Roasting Processes

The volatile compounds from insects (Tenebrio molitor and Zophobas morio larvae) roasted at 160, 180, or 200 °C and fed with potato starch or blue corn flour were isolated by solid-phase microextraction (SPME), and identified by gas chromatography–mass spectrometry (GC-MS). In the tested material, 48 volatile compounds were determined. Among them, eight are pyrazines, aroma compounds that are formed in food products during thermal processing due to the Maillard reaction. Eleven of the identified compounds influenced the roast, bread, fat, and burnt aromas that are characteristic for traditional baked dishes (meat, potatoes, bread). Most of them are carbonyl compounds and pyrazines. To confirm the contribution of the most important odorants identified, their odor potential activity values (OAVs) and %OAV were calculated. The highest value was noted for isobuthylpyrazine, responsible for roast aroma (%OAV > 90% for samples roasted at lower temperatures), and 2,5-dimethylpyrazine, responsible for burnt aroma (%OAV > 20% for samples roasted at the highest temperature). According to the study, the type of feed did not significantly affect the results of the sensory analysis of roasted insects. The decisive influence was the roasting temperature. The highest scores were achieved for Tenebrio molitor larvae heat-treated at 160 °C.

Stereoselective synthesis of (6Z,8E)-undeca-6,8,10-trien-3-one (yuzunone) for its characterization in yuzu and various citrus essential oils

(6Z,8E)-Undeca-6,8,10-trien-3-one (yuzunone) is reported to be one of the main olfactory contributors of the specific fruity-green-balsamic odor of yuzu peel oil. Using an original stereoselective synthesis, we prepared a pure sample of yuzunone, which was used as a reference compound to check its presence by GC-MS and GC-O in 5 commercial samples of yuzu and citrus essential oils. Surprisingly, we could not detect yuzunone by GC-MS in any of our samples. However, it could be detected by a small part of the panelists involved in GC-O/AEDA experiments in a yuzu commercial oil, but its olfactory contribution proved to be very limited.

In-vivo biotransformation of citrus functional components and their effects on health

Citrus, one of the most popular fruits worldwide, contains various functional components, including flavonoids, dietary fibers (DFs), essential oils (EOs), synephrines, limonoids, and carotenoids. The functional components of citrus attract special attention due to their health-promoting effects. Food components undergo complex biotransformation by host itself and the gut microbiota after oral intake, which alters their bioaccessibility, bioavailability, and bioactivity in the host body. To better understand the health effects of citrus fruits, it is important to understand the in-vivo biotransformation of citrus functional components. We reviewed the biotransformation of citrus functional components (flavonoids, DFs, EOs, synephrines, limonoids, and carotenoids) in the body from their intake to excretion. In addition, we described the importance of biotransformation in terms of health effects. This review would facilitate mechanistic understanding of the health-promoting effect of citrus and its functional components, and also provide guidance for the development of health-promoting foods based on citrus and its functional components.

Sesquiterpenes in grapes and wines: Occurrence, biosynthesis, functionality, and influence of winemaking processes

Grapes are an important global horticultural product, and are mainly used for winemaking. Typically, grapes and wines are rich in various phytochemicals, including phenolics, terpenes, pyrazines, and benzenoids, with different compounds responsible for different nutritional and sensory properties. Among these compounds, sesquiterpenes, a subcategory of the terpenes, are attracting increasing interest as they affect aroma and have potential health benefits. The characteristics of sesquiterpenes in grapes and wines in terms of classification, biosynthesis pathway, and active functions have not been extensively reviewed. This paper summarizes 97 different sesquiterpenes reported in grapes and wines and reviews their biosynthesis pathways and relevant bio-regulation mechanisms. This review further discusses the functionalities of these sesquiterpenes including their aroma contribution to grapes and wines and potential health benefits, as well as how winemaking processes affect sesquiterpene concentrations.

Biosynthesis of Stereoisomers of Dill Ether and Wine Lactone by Pleurotus sapidus

The white-rot fungus Pleurotus sapidus (PSA) biosynthesizes the bicyclic monoterpenoids 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (dill ether) (1) and 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3H)-one (wine lactone) (2). Submerged cultures grown in different media were analyzed by gas chromatography-mass spectrometry. The stereochemistry of the formed isomers was elucidated by comparing their retention indices to those of reference compounds by enantioselective multidimensional gas chromatography. The basidiomycete produced the rare (3R,3aR,7aS) and (3S,3aR,7aS) stereoisomers of dill ether and wine lactone. Kinetic analyses of the volatilome and bioprocess parameters revealed that the biosynthesis of the bicyclic monoterpenoids correlated with the availability of the primary carbon source glucose. Spiking the media with ¹³C-labeled glucose demonstrated that the compounds were produced de novo. Supplementation studies i.a. with isotopically labeled substrates further identified limonene and p-menth-1-en-9-ol as intermediate compounds in the fungal pathways. PSA was able to biotransform all enantiomeric forms of the latter compounds to the respective isomers of dill ether and wine lactone.

Volatile Compounds in Citrus Essential Oils: A Comprehensive Review

The essential oil fraction obtained from the rind of Citrus spp. is rich in chemical compounds of interest for the food and perfume industries, and therefore has been extensively studied during the last decades. In this manuscript, we provide a comprehensive review of the volatile composition of this oil fraction and rind extracts for the 10 most studied Citrus species: C. sinensis (sweet orange), C. reticulata (mandarin), C. paradisi (grapefruit), C. grandis (pummelo), C. limon (lemon), C. medica (citron), C. aurantifolia (lime), C. aurantium (bitter orange), C. bergamia (bergamot orange), and C. junos (yuzu). Forty-nine volatile organic compounds have been reported in all 10 species, most of them terpenoid (90%), although about half of the volatile compounds identified in Citrus peel are non-terpenoid. Over 400 volatiles of different chemical nature have been exclusively described in only one of these species and some of them could be useful as species biomarkers. A hierarchical cluster analysis based on volatile composition arranges these Citrus species in three clusters which essentially mirrors those obtained with genetic information. The first cluster is comprised by C. reticulata, C. grandis, C. sinensis, C. paradisi and C. aurantium, and is mainly characterized by the presence of a larger abundance of non-terpenoid ester and aldehyde compounds than in the other species reviewed. The second cluster is comprised by C. junos, C. medica, C. aurantifolia, and C. bergamia, and is characterized by the prevalence of mono- and sesquiterpene hydrocarbons. Finally, C. limon shows a particular volatile profile with some sulfur monoterpenoids and non-terpenoid esters and aldehydes as part of its main differential peculiarities. A systematic description of the rind volatile composition in each of the species is provided together with a general comparison with those in leaves and blossoms. Additionally, the most widely used techniques for the extraction and analysis of volatile Citrus compounds are also described.

Determination of Volatile Flavour Profiles of Citrus spp. Fruits by SDE-GC-MS and Enantiomeric Composition of Chiral Compounds by MDGC-MS

INTRODUCTION

Citrus fruits are known to have characteristic enantiomeric key compounds biosynthesised by highly stereoselective enzymatic mechanisms. In the past, evaluation of the enantiomeric ratios of chiral compounds in fruits has been applied as an effective indicator of adulteration by the addition of synthetic compounds or natural components of different botanical origin.

OBJECTIVE

To analyse the volatile flavour compounds of Citrus junos Sieb. ex Tanaka (yuzu), Citrus limon BURM. f. (lemon) and Citrus aurantifolia Christm. Swingle (lime), and determine the enantiomeric ratios of their chiral compounds for discrimination and authentication of extracted oils.

METHODOLOGY

Volatile flavour compounds of the fruits of the three Citrus species were extracted by simultaneous distillation extraction and analysed by gas chromatography-mass spectrometry. The enantiomeric composition (ee%) of chiral camphene, sabinene, limonene and β-phellandrene was analysed by heart-cutting multidimensional gas chromatography-mass spectrometry.

RESULTS

Sixty-seven (C. junos), 77 (C. limon) and 110 (C. aurantifolia) volatile compounds were identified with limonene, γ-terpinene and linalool as the major compounds. Stereochemical analysis (ee%) revealed 1S,4R-(-) camphene (94.74, 98.67, 98.82), R-(+)-limonene (90.53, 92.97, 99.85) and S-(+)-β-phellandrene (98.69, 97.15, 92.13) in oil samples from all three species; R-(+)-sabinene (88.08) in C. junos; and S-(-)-sabinene (81.99, 79.74) in C. limon and C. aurantifolia, respectively.

CONCLUSION

The enantiomeric composition and excess ratios of the chiral compounds could be used as reliable indicators of genuineness and quality assurance of the oils derived from the Citrus fruit species. Copyright © 2017 John Wiley & Sons, Ltd.

Bio-oil production of softwood and hardwood forest industry residues through fast and intermediate pyrolysis and its chromatographic characterization

Bio-oils were produced through intermediate (IP) and fast pyrolysis (FP), using Eucalyptus sp. (hardwood) and Picea abies (softwood), wood wastes produced in large scale in Pulp and Paper industries. Characterization of these bio-oils was made using GC/qMS and GC×GC/TOFMS. The use of GC×GC provided a broader characterization of bio-oils and it allowed tracing potential markers of hardwood bio-oil, such as dimethoxy-phenols, which might co-elute in 1D-GC. Catalytic FP increased the percentage of aromatic hydrocarbons in P. abies bio-oil, indicating its potential for fuel production. However, the presence of polyaromatic hydrocarbons (PAH) draws attention to the need of a proper management of pyrolysis process in order to avoid the production of toxic compounds and also to the importance of GC×GC/TOFMS use to avoid co-elutions and consequent inaccuracies related to identification and quantification associated with GC/qMS. Ketones and phenols were the major bio-oil compounds and they might be applied to polymer production.

Chemical Composition and Characteristic Odor Compounds in Essential Oil from Alismatis Rhizoma (Tubers of Alisma orientale)

Chemical composition and potent odorants that contribute to the characteristic odor of essential oil from Alismatis Rhizoma (tubers of Alisma orientale) were investigated by gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), aroma extract dilution analysis (AEDA) and relative flavor activity (RFA) methods. Fifty components, representing 94.5% of the total oil, were identified. In this study, we newly identified thirty-nine compounds in the oil from tubers of A. orientale. The major constituents of the essential oil were khusinol (36.2%), δ-elemene (12.4%), germacron (4.1%), alismol (3.8%), β-elemene (3.1%), and α-bisabolol (1.9%). Through sensory analysis, sixteen aroma-active compounds were detected and the key contributing aroma-active compounds were δ-elemene (woody, flavor dilution (FD)-factor = 4, RFA = 0.3) β-elemene (spicy, FD = 5, RFA = 0.7), spathulenol (green, FD = 5, RFA = 1.0), γ-eudesmol (woody, FD = 6, RFA = 1.5), and γ-cadinol (woody, FD = 5, RFA = 1.0). These compounds are thought to contribute to the odor from tubers of A. orientale. These results imply that the essential oil from the tubers of A. orientale deserve further investigations in the phytochemical and medicinal fields.

Chemical and biological characterization of novel essential oils from Eremophila bignoniiflora (F. Muell) (Myoporaceae): a traditional Aboriginal Australian bush medicine

Essential oils were extracted by hydrodistillation from the traditional Australian medicinal plant Eremophila bignoniiflora, characterized chemically and then screened for bioactivity. Characterization and quantification were completed using gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detection, respectively. Antimicrobial capacity was assessed using disc diffusion and micro-titre plate broth dilution and further characterized using thin layer chromatography followed by bioautography to assign activity to separated individual active components. Antifungal capacity was investigated using micro-titre plate broth dilution against pathogenic Trichophyton species. Free radical scavenging ability was assessed using the diphenylpicrylhydradyl reaction in methanol. The predominant components of the essential oil were fenchyl-acetate and bornyl-acetate. However, bioautography indicated antimicrobial ability to be largely linked to the less abundant, more polar constituents. Oils displayed only modest antifungal ability against pathogenic Trichophyton species associated with dermatophytosis, but moderate to high antimicrobial activity, particularly against the yeast Candida albicans and the bacteria Staphylococcus epidermidis. Essential oils exhibited relatively low free radical scavenging ability. Speculation over the role of essential oils in the traditional medicinal applications of E. bignoniiflora follows, exploring correlations between traditional use and investigated bioactivities.

Volatile constituents of wild citrus Mangshanyegan (Citrus nobilis Lauriro) peel oil

Volatiles of a wild mandarin, Mangshanyegan (Citrus nobilis Lauriro), were characterized by GC-MS, and their aroma active compounds were identified by aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry (GC-O). The volatile profile of Mangshanyegan was compared with those of other four citrus species, Kaopan pummelo (Citrus grandis), Eureka lemon (Citrus limon), Huangyanbendizao tangerine (Citrus reticulata), and Seike navel orange (Citrus sinensis). Monoterpene hydrocarbons predominated in Mangshanyegan, in particular d-limonene and β-myrcene, which accounted for 85.75 and 10.89% of total volatiles, respectively. Among the 12 compounds with flavor dilution factors (FD) = 27, 8 oxygenated compounds, including (Z)- and (E)-linalool oxides, were present only in Mangshanyegan. The combined results of GC-O, quantitative analysis, odor activity values (OAVs), and omission tests revealed that β-myrcene and (Z)- and (E)-linalool oxides were the characteristic aroma compounds of Mangshanyegan, contributing to the balsamic and floral notes of its aroma.

Design and performance of a compact Li+ ion attachment mass spectrometry system with an atmospheric sampling device

This report describes the development of a compact ion attachment mass spectrometry system. A single turbomolecular pump was employed to fill the basic requirements for vacuum conditions simply and cost-effectively, without the need for a differential pumping stage. A Li(+) ion source was placed in the first of two vacuum chambers; a 0.4 mm aperture allowed the product ions to enter the second chamber for mass analysis. With the present system, any chemical species, including radical intermediates, can be detected at atmospheric pressure in real-time. The minimum detectable amount (at S/N = 3) of toluene was around 1.3 × 10(-12) g/s with a linearity greater than 10(4). For illustrative purposes, we tested the system on laboratory air and on aroma compounds in the headspace of the Yuzu plant, Citrus junos.

Effect of irradiation, active and modified atmosphere packaging, container oxygen barrier and storage conditions on the physicochemical and sensory properties of raw unpeeled almond kernels (Prunus dulcis)

BACKGROUND

The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high-barrier pouches, under N(2) or with an O(2) absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated.

RESULTS

Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N(2) , atmosphere L and b values decreased during storage with a parallel increase of value a resulting to gradual product darkening especially in irradiated samples.

CONCLUSION

Non-irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O(2) absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET-SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET-SiOx//LDPE stored in the dark.

Volatile compounds with characteristic odour in moso-bamboo stems (Phyllostachys pubescens Mazel ex Houz. De ehaie)

INTRODUCTION

Moso-bamboo (Phyllostachys pubescens) is well known as an edible shoot in Asia, and the stems of moso-bamboo are used as tableware due to its characteristic odour. Despite the pleasant odour of bamboo stems, no detailed analysis of the volatile compounds has been reported.

OBJECTIVE

To clarify the potent odourants contributing to the characteristic aroma of the bamboo, the aroma extract dilution analysis (AEDA) method was performed through gas chromatography olfactometry (GC-O) analysis. In addition, relative flavour activity (RFA) was calculated, in which both the flavor dilution (FD) factor and weight percentage of each compound are involved.

RESULTS

Eighty-nine compound in bamboo stems oil were identified by GC and GC-MS. The main components of the oil were palmitic acid (16.5%), (E)-nerolidol (10.2%) and indole (8.1%). In sensory analysis, 18 aroma-active compounds were detected by aroma extract dilution analysis (AEDA). The most intense aroma-active compounds were eugenol (sweet, clove-like, green) and (E)-2-nonenal (green).

CONCLUSION

The results of the sniffing test, RFA and FD factor indicated that (E)-2-nonenal and eugenol were estimated to have a bamboo-like aroma, and aldehyde compounds, such as a phenylacetaldehyde (floral) and C9-C10 unsaturated aldehydes, make the aroma of bamboo.

Novel character impact compounds in Yuzu (Citrus junos Sieb. ex Tanaka) peel oil

Yuzu ( Citrus junos Sieb. ex Tanaka), a tree-grown fruit similar to a kind of sour orange, is widely used in Japanese food/cooking for its pleasant flavor. To clarify the odor-active volatiles that differentiate yuzu from other citrus fruits, sensory evaluations were conducted on yuzu peel oil. The results revealed that the polar part of yuzu peel oil was the source of the characteristic aroma of fresh yuzu fruit. By aroma extract dilution analysis (AEDA) of the polar volatile part of yuzu peel oil, seven odorants were newly identified as odor-active volatiles in yuzu peel oil in the highest flavor dilution (FD) factors of 128 and 32: oct-1-en-3-one, (E)-non-4-enal, (E)-dec-4-enal, 4-methyl-4-mercaptopentan-2-one, (E)-non-6-enal, (6Z,8E)-undeca-6,8,10-trien-3-one (Yuzunone), and (6Z,8E)-undeca-6,8,10-trien-4-ol (Yuzuol). Among the most odor-active volatiles in yuzu, (E)-non-6-enal and Yuzunone were identified for the first time solely in yuzu peel oil and not in the peel of other citrus species, and Yuzuol was identified for the first time in nature. Sensory evaluation of yuzu aroma reconstitutions revealed that the newly identified compound, Yuzunone, contributes greatly to the distinct yuzu aroma.

Evaluation of aroma-active compounds in Pontianak orange peel oil ( Citrus nobilis Lour. Var. microcarpa Hassk.) by gas chromatography-olfactometry, aroma reconstitution, and omission test

The aroma-active compounds of Pontianak orange peel oil ( Citrus nobilis Lour. var. microcarpa Hassk.) were characterized by using gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA) techniques. Forty-one compounds were found to be aroma-active, which were mainly dominated by saturated and unsaturated aldehydes. The flavor dilution (FD) factor was within the range of 2-2048, and compounds having the highest FD factor were alpha-pinene, beta-pinene, linalool, and 2-methoxy-3-(2-methylpropyl) pyrazine, including a few unknown compounds. On the basis of GC-O results, odor activity value (OAV) and relative flavor activity (RFA) were determined for aroma model reconstitution. These resembled the original aroma of the peel oil for the green, fatty, fresh, peely, floral, and tarry attributes, with the model solution derived from OAV being the closest to Pontianak oil. Omission tests were carried out to verify the significance of (Z)-5-dodecenal and 1-phenylethyl mercaptan as key compounds in the aroma of Pontianak orange peel oil.

Improvement of texture properties and flavor of frozen dough by carrot (Daucus carota) antifreeze protein supplementation

The effects of concentrated carrot protein (CCP) containing 15.4% (w/w) carrot (Daucus carota) antifreeze protein on texture properties of frozen dough and volatile compounds of crumb were studied. CCP supplementation lowered the freezable water content of the dough, resulting in some beneficial effects including holding loaf volume steadily and making the dough softer and steadier during frozen storage. Furthermore, SPME-GC-MS analysis showed CCP supplementation did not give any negative influences on volatile compounds of crumb and gave a pleasant aroma felt like Michelia alba DC from trans-caryophyllene simultaneously. Combining our previous results that CCP supplementation improves the fermentation capacity of the frozen dough, CCP could be used as a beneficial additive for frozen dough processing.

Identification of aroma active compounds in orange essence oil using gas chromatography-olfactometry and gas chromatography-mass spectrometry

Using GC-MS and GC-flame ionization detection (FID)/olfactometry, 95 volatile components were detected in orange essence oil, of which 55 were aroma active. In terms of FID peak area the most abundant compounds were: limonene, 94.5%; myrcene, 1%; valencene, 0.8%; linalool, 0.7%, and octanal, decanal, and ethyl butyrate, 0.3% each. One hundred percent of the aroma activity was generated by slightly more than 4% of the total volatiles. The most intense aromas were produced by octanal, wine lactone, linalool, decanal, beta-ionone, citronellal, and beta-sinensal. Potent aroma components reported for the first time in orange essence oil include: E-2-octenal, 1-octen-3-ol, Z-4-decenal, E,E-2,4-nonadienal, guaiacol, gamma-octalactone, and m-cresol. Over 20 compounds were identified for the first time in orange essence oil using MS, however, most did not exhibit aroma activity.

Techniques for gas chromatography of volatile terpenoids from a range of matrices

The commercial importance of the volatile mono- and sesqui-terpenoids has resulted in a wide range of techiques being used for extraction, concentration, chromatography, and characterisation of constituents. The major chromatographic technique is gas chromatography, and tandem techniques of chromatography linked to further chromatography and spectroscopy, allow much increased resolution, and greater ease of characterisation of terpenes. A wide range of extraction techniques are discussed, and suitability for particular matrices and sample sizes outlined. Chromatography operating conditions and stationary phases, and techniques for solute identification are laid out. A number of applications of terpene analysis in many different matrices are discussed.