Composition analysis and health risk assessment of the hazardous compounds in cooking fumes emitted from heated soybean oils with different refining levels.

The cooking fumes generated from thermal cooking oils contains various of hazardous components and shows deleterious health effects. The edible oil refining is designed to improve the oil quality and safety. While, there remains unknown about the connections between the characteristics and health risks of the cooking fumes and oils with different refining levels. In this study, the hazardous compounds, including aldehydes, ketones, polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) in the fumes emitted from heated soybean oils with different refining levels were characterized, and their health risks were assessed. Results demonstrated that the concentration range of aldehydes and ketones (from 328.06 ± 24.64 to 796.52 ± 29.67 µg/m3), PAHs (from 4.39 ± 0.19 to 7.86 ± 0.51 µg/m3), and PM (from 0.36 ± 0.14 to 5.08 ± 0.15 mg/m3) varied among soybean oil with different refining levels, respectively. The neutralized oil showed the highest concentration of aldehydes and ketones, whereas the refined oil showed the lowest. The highest concentration levels of PAHs and PM were observed in fumes emitted from crude oil. A highly significant (p < 0.001) positive correlation between the acid value of cooking oil and the concentrations of PM was found, suggesting that removing free fatty acids is critical for mitigating PM concentration in cooking fumes. Additionally, the incremental lifetime cancer risk (ILCR) values of PAHs and aldehydes were 5.60 × 10-4 to 8.66 × 10-5 and 5.60 × 10-4 to 8.66 × 10-5, respectively, which were substantially higher than the acceptable levels (1.0 × 10-6) established by US EPA. The present study quantifies the impact of edible oil refining on hazardous compound emissions and provides a theoretical basis for controlling the health risks of cooking fumes via precise edible oil processing.

Chemometrics-based investigation of non-volatiles/volatiles flavor of tencha (Camellia sinensis cv. Yabukita, Longjing 43 and Baiye 1).

The increasing demand for tea consumption calls for the development of more products with distinct characteristics. The sensory quality of tencha is significantly determined by innate differences among tea cultivars. However, the correlations between the chemical composition and sensory traits of tencha are still unclear. To enhance the understanding of the flavor formation mechanism in tencha and further to develop new cultivars resources, we investigated non-volatiles and volatile metabolites as well as sensory traits in tencha from different tea cultivars (Camellia sinensis cv. Yabukita, Longjing 43 and Baiye 1); the relationships between the flavor traits and non-volatiles/volatiles were further evaluated by partial least squares - discriminate analysis (PLS-DA), multiple factor analysis (MFA) and multidimensional alignment (MDA) analysis. A total of 64 non-volatiles and 116 volatiles were detected in all samples, among which 71 metabolites were identified as key flavor-chemical contributors involving amino acids, flavonol glycosides, flavones, catechins, ketones, alcohols, hydrocarbons, aldehydes, esters and acids. The levels of taste-related amino acids, flavonol glycosides and gallic acid varied significantly among the tencha samples made from different tea cultivars. All the samples exhibited typical quality characteristics of tencha. The tencha from Camellia sinensis cv. Longjing 43 and Camellia sinensis cv. Baiye 1 (cultivated in the open) exhibited higher levels of amino acids and gallic acid, which were associated with the umami taste and mellow taste of tea infusion. Abundant flavonol glycosides were related to the astringency, while partial tri-glycosides specifically quercetin-3-O-galactoside-rhamnoside-glucoside and total of flavonol galactoside-rhamnoside-glucoside were associated with mellow taste. The floral alcohols were identified as significant contributors to the refreshing aroma traits of tencha. The green, almond-like, acidic and fruity odorants were associated with a green and fresh aroma, while the green, cheesy and waxy odorants such as ketones, esters, acids and hydrocarbons were associated with seaweed-like aroma. This study provides insight into sensory-related chemical profiles of tencha from different tea cultivars, supplying valuable information on flavor and quality identification for tencha.

Leaf cuticular waxes of wild-type Welsh onion (Allium fistulosum L.) and a wax-deficient mutant: Compounds with terminal and mid-chain functionalities.

Plant cuticles cover aerial organs to limit non-stomatal water loss and protect against insects and pathogens. Cuticles contain complex mixtures of fatty acid-derived waxes, with various chain lengths and diverse functional groups. To further our understanding of the chemical diversity and biosynthesis of these compounds, this study investigated leaf cuticular waxes of Welsh onion (Allium fistulosum L.) wild type and a wax-deficient mutant. Leaf waxes were extracted with chloroform, separated using thin layer chromatography (TLC), and analyzed using gas chromatography-mass spectrometry (GC-MS). The extracts contained typical wax compound classes found in nearly all plant lineages but also two uncommon compound classes. Analyses of characteristic MS fragmentation patterns followed by comparisons with synthetic standards identified the latter as very-long-chain ketones and primary ketols. The ketols were minor compounds, with chain lengths ranging from C28 to C32 and carbonyls mainly on C-18 and C-20 in wild type wax, and a C28 chain with C-16 carbonyl in the mutant. The ketones made up 70% of total wax in the wild type, consisting mainly of C31 isomers with carbonyl group on C-14 or C-16. In contrast, the mutant wax comprised only 4% ketones, with chain lengths C27 and C29 and carbonyls predominantly on C-12 and C-14, respectively. A two-carbon homolog shift between wild type and mutant was also observed in the primary alcohols (a major wax compound class), whilst alkanes exhibited a four-carbon shift. Overall, the compositional data shed light on possible biosynthetic pathways to wax ketones that can be tested in future studies.

Aryl ketones-derived porous organic polymer for enrichment and sensitive detection of phenylurea herbicides in water, tea drink and mushroom samples.

Three aryl ketones-derived porous organic polymers (ATP-POPM, ATP-POPP and ATP-POPO) were fabricated through the aldol condensation reaction of acetylated triphenylsilane precursor (ATP) with different aromatic aldehydes for the first time. The ATP-POPM exhibited superior extraction capacity toward phenylurea herbicides (PUHs). A sensitive method for the simultaneous determination of six PUHs in water, tea drink and mushroom samples was developed with ATP-POPM as solid phase extraction adsorbent prior to high performance liquid chromatography ultraviolet detection. Under the optimized conditions, the linear response of PUHs was 0.09-80.0 ng mL-1 for water, 0.18-100.0 ng mL-1 for tea drinks and 4.50-200.0 ng g -1 for mushroom samples. The detection limits (S/N=3) of the method were 0.03-0.10 ng mL-1, 0.06-0.18 ng mL-1, 1.50-4.50 ng g -1 for water, tea drink and mushroom, respectively. The method recoveries for spiked samples were in the range of 80.7%-116.0%, with relative standard deviations less than 10.3%. The results proved that the established method was sensitive and suitable to detect PUHs with acceptable accuracy and precision. This work provided a powerful tool to synthesize promising adsorbent by aldol condensation reaction for detecting six PUHs simultaneously in real samples.

Fast and Non-Destructive Profiling of Commercial Coffee Aroma under Three Conditions (Beans, Powder, and Brews) Using GC-IMS.

The flavor of coffee can be affected by the preparation parameters. In this investigation, the flavor profiles of three coffee brands under three conditions (bean, powder, and brew) were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and the electronic nose (E-nose). The flavor results were further studied using multiple factor analysis (MFA). A total of 117 peaks were identified in all coffee samples by GC-IMS, and the principal component analysis (PCA) showed these coffee samples could be grouped and separated. A total of 37 volatile organic compounds (VOCs) were selected as biomarkers to distinguish coffee samples, including 5 aldehydes, 10 ketones, 8 alcohols, 2 acids, 4 esters, 5 furans, and 3 other compounds. The comparison between E-nose and GC-IMS data using partial least squares regression (PLSR) and MFA showed GC-IMS could present very close sample spaces. Compared with E-nose, GC-IMS could not only be used to classify coffee samples in a very short time but also provide VOC bio-markers to discriminate coffee samples.

Comprehensive Evaluation of Quality of Camellia semiserrata Seed Oils from Various Harvest Dates.

The ripening degree of camellia fruit is one of the key factors affecting the quality of camellia seed oil. In this study, taking Camellia semiserrata as the research object, the oil content, physicochemical indexes, nutritional indexes, fatty acid composition, and volatile compounds of camellia seed oils from various harvest dates (from September to October) were determined. The results showed that with the increase of the ripening degree of camellia fruit, the oil content of camellia seed increased at first and then decreased and reached the highest (58.74%) on September 30, while the acid value, peroxide value, ß-sitosterol, α-tocopherol, and polyphenols of camellia seed oil showed a downward trend. Among them, the highest contents of ß-sitosterol, α-tocopherol, and polyphenols were observed on September 2, which were 6881.60, 311.34, and 78.08 mg/kg, respectively. In terms of the fatty acid composition of camellia seed oils, the content of oleic acid increased at first and then decreased, the content of linoleic acid and palmitic acid decreased gradually, while the content of stearic acid increased gradually. A total of 37 volatile compounds were identified in different samples, including 12 aldehydes, 5 ketones, 12 alcohols, 2 acids, 5 esters, and 1 other. With the increase of the ripening degree, the concentration of aldehydes and alcohols increased at first and then decreased, the concentration of ketones and esters decreased gradually, but the concentration of acid compounds had no obvious rule. In addition, the camellia seed oils from various harvest dates were classified and comprehensively evaluated by principal component analysis and grey relation analysis. The results showed that different camellia seed oils could be divided into three groups, and the comprehensive score of camellia seed oils on September 30 was the highest. In general, this work can provide theoretical guidance for the harvest date of Camellia semiserrata.

Characterization of Warmed-Over Flavor Compounds in Surimi Gel Made from Silver Carp (Hypophthalmichthys molitrix) by Gas Chromatography-Ion Mobility Spectrometry, Aroma Extract Dilution Analysis, Aroma Recombination, and Omission Studies.

The warmed-over flavor (WOF) in surimi gels was characterized by gas chromatography-ion mobility spectrometry, aroma extract dilution analysis, aroma recombination, and omission studies. Surimi gels with different WOF levels were prepared by different gelling temperatures, and surimi gels heated at 90, 100, and 121 °C were considered as the samples with light, strong, and medium WOF, respectively. Based on the quantification and odor activity values, 14 aldehydes, 2 ketones, 3 alcohols, 2 benzene-containing compounds, 2 N-containing compounds, 3 S-containing compounds, 3 lactones, undecanoic acid, and 4-methylphenol were recombined to build a spiked model for surimi gels with the strongest WOF, which showed the highest similarity with the original sample. Finally, a triangle test involving omission of the aroma compounds from the spiked model proved that the WOF in surimi gels was attributed to (E,E)-2,4-decadienal, heptanal, octanal, nonanal, decanal, (E)-2-nonenal, (E)-2-octenal, (E)-2-decenal, (E,E)-2,4-heptadienal, 2,3-pentanedione, 2,6-dimethylpyrazine, 2-propylpyridine, benzothiazole, 2-methoxybenzenethiol, and 2-furfurylthiol.

Composition and Insecticidal Activity of Elsholtzia kachinensis Prain, a Traditional Vegetable and Herbal Medicine.

In recent years, secondary metabolites of plants have attracted researchers' interest as a substitute for synthetic insecticides with many advantages. Elsholtzia kachinensis is an annual herb with medicinal and edible value. In this study, the essential oil (EO) of the aerial part of E. kachinensis was extracted by hydrodistillation, and GC-MS analysed essential oil components. The results show that carvone and dehydroelsholtzia ketone are the main components of the essential oil, accounting for 32.298% and 31.540%, respectively. EO, carvone and dehydroelsholtzia ketone are used to determine the effects against stored-product insects Lasioderma serricorne, Tribolium castaneum, Sitophilus oryzae and Liposcelis bostrychophila. The essential oil showed the most vital contact and fumigation toxicity to L. serricorne, of which LD50 and LC50 values were 3.85 µg/adult and 7.74 mg/L air, respectively. S. oryzae did not show repellent activity, but the repellent rate of the other three species reached 90% under EO treatment at a concentration of 78.63 nL/cm2. Therefore, the essential oil of E. kachinensis has an insecticidal effect and has the potential to be developed as a new eco-friendly insecticide.

Influence of Eurotium cristatum and Aspergillus niger individual and collaborative inoculation on volatile profile in liquid-state fermentation of instant dark teas.

The three instant dark teas were produced from instant green tea (IGT) by liquid-state fermentations using the microorganisms Eurotium cristatum (EFT), Aspergillus niger (AFT), and sequential inoculation of E. cristatum/A. niger (EAFT), respectively. The volatile compounds of four tea samples were extracted by headspace-solid phase microextraction (HS-SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS) coupled with chemometrics. A total of 97 volatile compounds were tentatively identified to distinguish three fermented instant dark from IGT. Alcohols, acids, esters, ketones, aldehydes, and heterocyclics could be clearly distinguished by principal component analysis (PCA), venn diagram, heatmap analysis and hierarchical cluster analysis (HCA). Descriptive sensory analysis revealed that AFT had a moldy, woody and herbal aroma; EFT showed woody and herbal aroma; and EAFT smelled an herbal, sweet, minty and floral aroma. This study indicates that fermentation using different microorganisms is critical in forming unique aroma characteristics of instant dark teas.

Quantitative Determination and Validation of Four Ketones in Salvia miltiorrhiza Bunge Using Quantitative Proton Nuclear Magnetic Resonance Spectroscopy.

Salvia mltiorrhiza Bunge (SMB) is native to China, whose dried root has been used as medicine. A few chromatographic- or spectrometric-based methods have already been used to analyze the lipid-soluble components in SMB. However, the methodology of qNMR on the extracts of fresh SMB root has not been verified so far. The purpose of this study was to establish a fast and simple method to quantify the tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone in fresh Salvia Miltiorrhiza Bunge root without any pre-purification steps using 1H-NMR spectroscopy. The process is as follows: first, 70% methanol aqueous extracts of fresh Salvia Miltiorrhiza Bunge roots were quantitatively analyzed for tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone using 1H-NMR spectroscopy. Different internal standards were tested and the validated method was compared with HPLC. 3,4,5-trichloropyridine was chosen as the internal standard. Twelve samples of Salvia Miltiorrhiza Bunge were quantitatively analyzed by qNMR and HPLC respectively. Then, the results were analyzed by chemometric approaches. This NMR method offers a fast, stable, and accurate analysis of four ketones: tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone in fresh roots of Salvia Miltiorrhiza Bunge.

Unveiling the bioactivity of Allium triquetrum L. lipophilic fractions: chemical characterization and in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus.

The lipophilic composition of Allium triquetrum L. bulbs, flowers and leaves was studied for the first time by GC-MS. Sixty compounds were firstly identified in A. triquetrum L. Fatty acids represented the major lipophilic family among the studied extracts, with (9Z,12Z,15Z)-octadeca-9,12,15-trienoic and (9Z,12Z)-octadeca-9,12-dienoic acids being the major constituents of this family. A long chain aliphatic ketone, namely hentriacontan-16-one, was mainly found in flowers and leaves. Flowers and leaves were also found to be rich in long chain aliphatic alkanes and alcohols, respectively. Sterols, monoglycerides, aromatic compounds and long chain aliphatic aldehydes were found in lower amounts. The antibacterial activity of A. triquetrum bulb, flower and leaf extracts against methicillin-resistant Staphylococcus aureus (MRSA) growth was in vitro assessed. Bulb and flower extracts showed significant MRSA growth inhibition. Overall, these valuable findings can contribute to the valorization of A. triquetrum L. as a source of value-added phytochemicals, specifically as antibacterial agents and for nutraceutical applications.

Supplementation of nicotinic acid to prepartum Holstein cows increases colostral immunoglobulin G, excretion of urinary purine derivatives, and feed efficiency in calves.

We evaluated the effects of incremental levels of unprotected nicotinic acid (NA) supplementation prepartum (0, 16, 32, or 48 g/d; CON, 16NA, 32NA, and 48NA, respectively) on colostrum yield and composition and cow and calf performance. Previous research indicated that 48 g/d of NA prepartum increased colostrum IgG concentration. Exact mechanisms for this increase are not clear. The effects of NA supplementation to prepartum cows on growth and performance of their calves have not been studied. Thirty-six multiparous Holstein cows housed in a tie-stall barn were blocked by expected calving date and randomly assigned to treatments at 4 wk prepartum. Blood samples were collected 3 times weekly for analysis of nonesterified fatty acids, ketones, and IgG. Urine samples were also collected 3 times weekly for analysis of creatinine and purine derivatives. Colostrum was collected within 90 min after parturition. Calves were removed from their dams before suckling, weighed within 30 min of birth, and received 4 L of maternal colostrum. The 38 calves born were blocked based on treatments of dams. All calves were fed 449 g dry matter (DM) of milk replacer (19.3% crude protein, 19.5% fat, DM basis) and a textured starter (41% starch, DM basis) at 2 d of age until weaning at 42 d, with water available ad libitum. Feeding NA resulted in linear decreases in DM intake in cows, but colostrum yield was not affected. Yield of metabolizable energy (ME) tended to change cubically, decreasing from control (CON) to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Concentration of IgG, protein, ash, and solids increased linearly with NA. Concentration of ME showed a tendency to increase quadratically with NA. Yield of IgG, fat, protein, and solids content increased quadratically with NA, while allantoin and total purine derivatives increased linearly. Calf 24-h IgG and apparent efficiency of absorption were not affected by NA. Calf ME intake from colostrum tended to increase quadratically with NA, but calf starter intake was not affected. Feed efficiency of calves increased quadratically with NA. Calf average daily gain changed cubically with NA, decreasing from CON to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Hip width gain, body length gain, and final body length changed cubically with NA, decreasing from CON to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Calf blood concentrations of ketones increased quadratically with NA. These data suggest that increasing levels of NA can be fed prepartum to increase colostral components and 32 g/d NA can improve calf performance.

[Discussion on medicinal value of Saposhnikoviae Radix based on difference of ketone content in cortex and wood of Saposhnikoviae Radix].

In order to confirm the tradition that bolting Saposhnikoviae Radix could not be used as medicine,the content of four chromone components in the cortex and wood of Saposhnikoviae Radix was analyzed by high performance liquid chromatography( HPLC),and the chemical fingerprints were established,12 common peaks were calibrated. The similarity analysis found that the similarity between batches was 0. 115-0. 995,it indicates that the cortex and wood of Saposhnikoviae Radix have certain differences. On this basis,systematic clustering analysis,principal component analysis and orthogonal partial least squares discriminant analysis were carried out with the content of four chromone components and whether they met the pharmacopoeia criteria as the original variables. The results showed that the content of the four components in the cortex of Saposhnikoviae Radix was much higher than that in the wood,and the four components detected were able to distinguish the cortex and the wood of Saposhnikoviae Radix. The results of the study reveal the tradition that bolting Saposhnikoviae Radix should not be used as medicine dut to decreased quality.

Assessment of volatile fingerprint by HS-SPME/GC-qMS and E-nose for the classification of cocoa bean shells using chemometrics.

The cocoa bean shell (CBS) is a main by-product of cocoa processing, with great potential to be used as an ingredient for functional foods because of its nutritional and flavour properties. This study aimed to characterise and classify CBSs obtained from cocoa beans of diverse cultivars and collected in different geographical origins through their volatile profile assessed using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-qMS) and E-nose combined with principal component analysis (PCA). The study provides, for the first time in a representative set of samples, a comprehensive fingerprint and semi-quantitative data for >100 volatile organic compounds (VOCs), such as aldehydes, ketones, pyrazines, alcohols, and acids. Through PCA, a clear separation of the Criollo cultivar from the other cultivars was achieved with both GC-qMS and E-nose analytical techniques because of the high content of key-aroma VOCs. Several biomarkers identified by GC-qMS, such as 2-hepanol, 2-methylpropanoic acid, and 2,3,5-trimethylpyrazine, recognized as key-aroma compounds for cocoa beans, were found suitable for the classification of CBSs according to their quality and origin. GC-qMS and E-nose appeared to be suitable analytical approaches to classify CBSs, with a high correlation between both analytical techniques. The volatile fingerprint and classification of CBSs could allow for the selection of samples with a specific flavour profile according to the food application and, therefore, constitute an interesting approach to valorise this by-product as a food ingredient.

Analysis of Chemical Composition of Extractives by Acetone and the Chromatic Aberration of Teak (Tectona Grandis L.F.) from China.

In order to clarify the chemical color change of teak (Tectona grandis L.F.), the difference of chemical composition between the heartwood and sapwood of teak was investigated by gas chromatography-mass spectrometry (GC-MS) based on the acetone extractive compounds. The results showed that the difference in content of the main components between heartwood and sapwood was not obvious. However, the amount of extractives in heartwood was higher than that in sapwood, especially for phenols, quinones, and ketones. The most obvious different substances in the acetone extractive between heartwood and sapwood were 4-tert-butyl-2-phenyl-phenol,2-methyl-anthraquinone, and 2,3-dimethyl-1,4,4a,9a-tetrahydro-9,10-anthracenedione, which might be the main composition for the chromatic aberration of teak. This paper focuses on a preliminary study and further work such as high-performance liquid chromatography (HPLC) with ultraviolet photometric detector (UV)/mass spectrometry (MS) will be carried out.

Formation of by-products during chemical interesterification of lipids. Detection and characterization of dialkyl ketones by non-aqueous reversed-phase liquid chromatography-high resolution mass spectrometry and gas chromatography-mass spectrometry.

A new class of foreign substances present in the unsaponifiable fraction of vegetable oils undergone to chemical interesterification was systematically investigated. Their chemical structure, corresponding to dialkyl ketones (DAK) molecules, was elucidated both by gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-high resolution mass spectrometry (LC-HRMS). An analytical protocol aimed to qualitative and quantitative detection of DAK molecules in vegetable oils of confectionery industry interest was developed. Being the range of concentration levels to be evaluated dependent on the technological task of interesterification process, the quantitation step was thoroughly examined. All the validation parameters were satisfactory and particularly the concentration determinations were made more reliable by the contemporary use of several quantitation standards. GC-MS and LC-HRMS analytical techniques exhibited comparable performances even if the second one shown better detection sensitivity.

Identification of Volatile Oxidation Compounds as Potential Markers of Walnut Oil Quality.

In this study, a 10-day accelerated storage at 60 °C was carried out to investigate the evolution of volatile profiles of walnut oils from three cultivars (cvs. Santai, Xiangling, Qingxiang). Eighteen volatile oxidation compounds, including three alcohols, 11 aldehydes, one furan, one ketone, and two acids, were identified in all oil samples. Data from the three cultivars were combined and the analysis showed that 2-heptenal and 1-octen-3-ol exhibited the strongest linear correlations with peroxide value (PV), p-anisidine value (p-AnV), and the residual content of total tocopherols (Rtocos ). The contents of both compounds were also proved to be significant variables for PV, p-AnV, and Rtocos , according to the jack-knife uncertainty test applied in partial least squares analysis. Hence, 2-heptenal and 1-octen-3-ol could be used as potential markers of walnut oil quality. Besides, the oleic-derived compounds such as octanal and nonanal were suggested to be used to indicate notable decrease of PUFAs during walnut oil oxidation, since they showed the strongest negative correlations with the residual content of PUFAs (RPUFAs ). PRACTICAL APPLICATION: Nowadays a large-scale planting of walnut has taken place in China. Since walnut contains more than 60% of oil, the development of walnut oil is of great significance. Volatiles such as aldehydes are secondary oxidation products. Study on the dynamic changes of their types and contents could be helpful to understand the process of walnut oil oxidation. The measurement of walnut oil quality could also be more convenient and predictable with the use of volatile markers. Hence, this research provides insights for the future development of online quality control system for walnut oil.

Effects of postharvest methyl jasmonate treatment on main health-promoting components and volatile organic compounds in cherry tomato fruits.

Effects of postharvest methyl jasmonate (MeJA) treatment on the contents of ascorbic acid and carotenoids, as well as the compositions and contents of volatile organic compounds (VOCs) in cherry tomato fruits were investigated during 11 days of storage at room temperature (25 °C). The results showed that MeJA treatment significantly increased the contents of ascorbic acid and carotenoids, especially lycopene in postharvest cherry tomato fruits. Moreover, MeJA treatment improved the contents of carotenoids derived VOCs such as 6-methyl-5-hepten-2-one (MHO), while had no effect on firmness, sugars and titratable acidity. All above results suggested that the exogenous MeJA application is potential in enhancement of main health-promoting components and VOCs in postharvest cherry tomato fruits.

Quantification of volatile compounds released by roasted coffee by selected ion flow tube mass spectrometry.

RATIONALE: The major objective of this exploratory study was to implement selected ion flow tube mass spectrometry, SIFT-MS, as a method for the on-line quantification of the volatile organic compounds, VOCs, in the headspace of the ground roasted coffee. METHODS: The optimal precursor ions and characteristic analyte ions were selected for real-time SIFT-MS quantification of those VOCs that are the most abundant in the headspace or known to contribute to aroma. NO+ reagent ion reactions were exploited for most of the VOC analyses. VOC identifications were confirmed using gas chromatography/mass spectrometry, GC/MS, coupled with solid-phase microextraction, SPME. RESULTS: Thirty-one VOCs were quantified, including several alcohols, aldehydes, ketones, carboxylic acids, esters and some heterocyclic compounds. Variations in the concentrations of each VOC in the seven regional coffees were typically less than a factor of 2, yet concentrations patterns characteristic of the different regional coffees were revealed by heat map and principal component analyses. The coefficient of variation in the concentrations across the seven coffees was typically below 24% except for furfural, furan, methylfuran and guaiacol. CONCLUSIONS: The SIFT-MS analytical method can be used to quantify in real time the most important odoriferous VOCs in ground coffee headspace to sufficient precision to reveal some differences in concentration patterns for coffee produced in different countries.

[Chemical constituents from Murraya euchrestifolia].

The open silica gel, ODS, and Sephadex LH-20 column chromatography, along with the semi-preparative HPLC was used to isolate and purify the chemical constituents from Murraya euchrestifolia. The structures of the isolates were elucidated by their physiochemical properties, NMR, and MS spectroscopic data, as well as comparison with literature data. Eighteen compounds were isolated from the CH2Cl2 fraction of the 95% aqueous EtOH extract of M. euchrestifolia, and their structures were identified as sakuranetin (1), eriodictyol-7,4'-dimethyl ether (2), isosakuranetin (3), 5-hydroxy-7,4'-dimethoxyflavanone (4), eriodictyol-7-methyl ether (5), lichexanthon (6), 5,6,7-trimethoxycoumarin (7), 5-hydroxy-6,8-dimethoxycoumarin (8), 8-hydroxy-6-methoxy-3-n-pentylisocoumarin (9), ethyl caffeate (10), 4-hydroxy-3,5- dimethoxycinnamic acid ethyl ester (11), methyl 3-(5'-hydroxyprenyl)-coumarate (12), (E)-coniferol (13), ß-hydroxypropiovanillone (14), 3-hydroxy-7,8-didehydro-ß-ionone (15), 3ß-hydroxy-5α, 6α-epoxy-7-megastigmen-9-one (16), grasshopper ketone (17), and 4-hydroxy-3,5-dimethoxybenzaldehyde (18). Compounds 1-15 and 18 were first obtained from the plants of Murraya genus, and compounds 16 and 17 were isolated from M. euchrestifolia for the first time.