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Plastic food contact materials (FCM)-based products were widely used in everyday life. These products were normally imposed to strict regulations in order to pass the enforcement tests of compliance as a prefix condition. However, even in these “qualified” materials, unknown chemical substances, not involving in legislation lists, could migrate from FCM. In this perspective, the present work aims to thoroughly analyze by means of Gas Chromatography-Mass Spectrometry (GC-MS) the different substances/migrants in 120 qualified FCM plastic products. Unexpectedly, among the identified compounds (nearly 100), only 13% was included in the permitted list of Commission Regulation EU No 10/2011. All the identified compounds were classified into 11 categories according to their chemical structure and the FCM type, whereas toxicology data were in addition analyzed. Each plastic type exhibited different preferences of chemical migrants. Fortunately, most of the compounds identified were of low toxicity, and only 4 chemicals were included in priority lists and previous literature reports as potential risk factors. Subsequently, the accurate amount of these 4 chemicals was determined. The amount of Bis(2-ethylhexyl) adipate (DEHA) and Bis(2-ethylhexyl) phthalate (DEHP) were lower than the SML in Commission Regulation EU No 10/2011, and that of stearamide was under the recommended use quantity. The 2,4-di-tert-butylphenol (2,4-DTBP) was widely exist in the investigated FCM products. Among them, the highest level is obtained in polypropylene/low density polyethylene (BOPP/LDPE) materials, up to 45.568±31.513 mg/kg. In summary, a panel of unlisted chemical migrants were discovered and identified by GS-MS screening. The results implied that plastic FCMs were not so “inert” as they usually considered, and further safety evaluation should be performed toward the complete identification of new substances in FCM products. [ABSTRACT FROM AUTHOR]

Aroma-active compounds of red radish pigment extracts (water extract, phosphoric acidified water extracts (PAW), 10 min water or phosphoric acidified water preheated extracts (HW or HPAW), Chongqing, and Yunan extracts) were identified and characterized via sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-mass spectrometry with olfactometry (GC-MS/O). Three sensory attributes, namely radish odor (desirable) and radish off-odor and sulfur-like odor (undesirable), were selected to characterize the red radish pigment extracts. The correlation between the aroma-active compounds (GC-MS) and sensory attributes was studied using partial least square regression (PLSR). The sensory evaluation results revealed that Chongqing (9.30 and 8.80), water (9.00 and 9.10), Yunan (7.80 and 8.00), and HW (6.90 and 7.20) extracts showed higher radish off-odor and sulfur-like odor scores, while PAW-2.5 (7.70) and HPAW-2.5 (7.60) extracts showed higher radish odor scores. Sulfur-containing compounds, allyl isothiocyanate, 1-butyl isothiocyanate, acetonitrile, oxygen-containing compounds, terpenes, and naphthalene were positively and significantly correlated with radish off-odor and sulfur-like odor but negatively and significantly correlated to radish odor. 3-(Methylthio)propyl isothiocyanate and pyridine were positively and significantly correlated to radish odor. Additionally, 3-buten-1-yl isothiocyanate and 4-(methylthio)-3-butenyl isothiocyanate showed positive but not significant impact on radish odor. Based on their higher volatile concentration, the aroma-active compounds of the four extracts were evaluated using GC-MS/O. Thirty-three aroma-active compounds with different odor intensities were identified to be the major odorant compounds for red radish pigment extracts by panelists. Conclusively, the red radish pigment extraction conditions play a great role in its sensory characteristics. [ABSTRACT FROM AUTHOR]

Changes in the aroma characteristics of mutton process flavors (MFSs) prepared from non-oxidized suet and oxidized suet (OS) of different oxidation degrees were assessed by GC-MS, descriptive sensory analysis (DSA), and electronic nose (E-nose). Six sensory attributes (muttony, meaty, suety, simulate, burnt, and off-flavor) were selected to assess MFSs. DSA results showed a distinct difference among the sample MFS1 with non-oxidized suet and other MFS samples with added OS of different oxidation degrees in terms of almost all sensory attributes. Also, MFS4 and MFS5 with moderate OS4 and OS5 showed very strong muttony, meaty, suety, and simulate attributes, but the weakest burnt and off-flavor attributes.GC-MSanalysis of volatiles indicated that MFS5, which had moderate OS5, generated a more appropriate content proportion of the characteristic flavor compounds than the others. Moreover, E-nose analysis confirmed the results of GC-MS and DSA. Results of correlation analysis among 19 selected odor-active compounds, DSA, and E-nose data further confirmed that the moderate OS with a peroxide value (PV) of 103.29-287.61meqO2 kg-1, the p-anisidine value (p-AV) of 61.03-262.52, and the acid value (AV) of 1.98-5.11mg KOH/g suet may be a desirable precursor for the sensory characteristics of MFS. [ABSTRACT FROM AUTHOR]

Ginger flavor beverages (GFBs) were sterilized using different methods including ultra-high-temperature sterilization (UHT) (135 °C, 5 s), atmospheric pressure sterilization (AP) (95 °C, 30 min), and high-pressure sterilization (HP) (121 °C, 15 min). Comparative study of flavor among beverages from different sterilization methods was performed using quantitative descriptive sensory analysis and electronic nose (EN) and gas chromatography-mass spectrometry (GC-MS). Seven attributes (fruity, floral, gingery, piquant, sweet, sour, and cooked) were selected to assess ginger beverage flavors. The odor profile features of GBFs from different sterilization methods were determined by EN, and fifty-nine volatile compounds were detected by GC-MS. Partial least squares regression (PLSR) was performed to analyze the correlation among data of quantitative descriptive sensory analysis, GC-MS data, and EN responses of GFBs. The results showed that nine volatile compounds, (E,E)-α-farnesene, eucalyptol, l-linalool, borneol, citronellol, β-bisabolol, geranial, bornyl acetate, and neryl acetate, had significant positive contribution to gingery note, and further, PLSR showed that AP was the most beneficial method to preserve these important volatile compounds. Conclusively, AP was chosen as the most favorable method for sterilization of clarified GFBs. [ABSTRACT FROM AUTHOR]

Abstract: Based on optimized solid-phase microextraction/gas chromatography–mass spectrometry (SPME/GC–MS) and chemometric methods, simple, reliable and reproducible methods were described for the first time for developing a chromatographic fingerprint of oxidized tallow. Eight optimal oxidized tallow samples were used to establish the chromatographic fingerprint. Spectral correlative chromatogram was adopted to identify 33 “common components”. The validation of fingerprint analysis was performed based on the relative retention time, the relative peak area of common peaks, sample stability and similarity analysis. The correlation coefficient of similarity of eight optimal oxidized tallow samples was more than 0.962, which showed that samples from different batches were consistent to some extent in spite of slightly different chemical indexes. Through principal component analysis (PCA), 14 constituents were further screened out to be the main chemical markers, which could be applied to more accurate quantitative discrimination and quality control of oxidized tallow. [Copyright &y& Elsevier]

Abstract: The “enzymatic hydrolysis-mild thermal oxidation” method was employed to obtain oxidized tallow. Nine beeflike flavours (BFs) were prepared through Maillard reaction with oxidized tallow and other ingredients. Volatile compounds of oxidized tallow and beeflike flavours were analysed by SPME/GC–MS. Six sensory attributes (meaty, beefy, tallowy, simulate, burnt and off-flavour) were selected to assess BFs. Thirty four odour-active compounds were identified to represent beef odour through GC–O analysis based on detection frequency method. GC–MS profiles of oxidized tallow were correlated with GC–O responses and sensory attributes of BFs using partial least squares regression modelling (PLSR). Twenty nine compounds were considered as the potential precursors of oxidized tallow. Among them, tetradecanoic acid, d-limonene, 1,7-heptandiol, 2-butyltetrahydrofuran, (Z)-4-undecenal, (Z)-4-decenal, (E)-4-nonenal and 5-pentyl-2(3H)-furanone were unique products generated from enzymatic hydrolysis-mild thermal oxidation of tallow, while hexanal, heptanal, octanal, nonanal, decanal, pentanal, acetic acid, butanoic acid, hexanoic acid, 1-heptanol, 1-octanol, 3-methylbutanal, 2-pentylfuran, γ-nonalactone, 2-undecenal, (E,E)-2,4-decadienal, (E,E)-2,4-nonadienal, (E)-2-nonenal, (E)-2-octenal, (E)-2-decenal and (Z)-2-heptenal were common products generated from thermal oxidation of tallow. [Copyright &y& Elsevier]

Abstract: Flavour profiles of seven beeflike process flavours (BFs) including non-oxidized or oxidized tallow were comparatively analysed by electronic nose, gas chromatography–mass spectrometry (GC–MS) and descriptive sensory analysis to characterize the headspace of BFs. Analysis of volatiles by GC–MS indicated that the effect of oxidized tallow with moderate oxidization level on Maillard reaction was more prominent than that of others, which potentially could result in an optimal meat flavour with strong, harmony and species-specific characteristics detected by sensory analysis. In addition, electronic nose data confirmed the accuracy of the GC–MS and sensory analysis results. Correlation analysis of the electronic nose measurements, sensory evaluation and characteristic compounds through Partial Least Squares Regression (PLSR) further explained that moderate oxidized tallow with peroxide value (PV) of 87.67–160mequiv./kg, the p-anisidine value (p-AV) of 30.57–50, and the acid value (AV) of 1.8–2.2mg KOH/g tallow was a desirable precursor for imparting aroma characteristics of beef flavour. [Copyright &y& Elsevier]

Abstract: To characterize the aroma of cherry wine, five samples were analyzed by quantitative descriptive sensory analysis, gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). The aroma of cherry wines was described by 6 sensory terms as fruity, sour, woody, fermentation, cameral and floral. Fifty-one odor-active (OA) compounds were detected by GC–O and quantified by GC–MS, and 45 of them were identified. Twenty-nine OA compounds having more than 50% detection frequency were selected as specific compounds correlated to sensory attributes by partial least squares regression (PLSR). The correlation result showed ethyl 2-methyl propionate, 2,3-butanedione, ethyl butyrate, ethyl pentanoate, 3-methyl-1-butanol, ethyl hexanoate, 3-hydroxy-2-butanone, ethyl lactate, 1-hexanol, (Z)-3-hexen-1-ol, ethyl hydroxyacetate, acetic acid, furfural, 2-ethyl-1-hexanol, benzaldehyde, propanoic acid, butanoic acid, guaiacol, beta-citronellol, hexanoic acid, 2-methoxy-4-methylphenol, 2-ethyl-3-hydroxy-4H-pyran-4-one, ethyl cinnamate, 2-methoxy-4-vinylphenol were typical OA compounds, which covaried with characteristic aroma of cherry wines. [Copyright &y& Elsevier]

Abstract: Thermal oxidation of tallow was assayed by peroxide value (PV), p-anisidine value (p-AV), and acid value (AV), and the volatile compounds produced at different oxidation conditions were analysed by SPME-GC/MS. The accumulation of characteristic beef flavour precursors, such as hexanal, 1-octen-3-ol, (E,E)-2,4-decadienal and (E,E)-2,4-heptadienal, reached a maximum value when heated at 140°C for 2h with an air flow of 75l/h per 100g tallow, whereas at the same temperature PV and p-AV were both at high levels, and AV was relatively low. A correlation analysis of chemical parameters and volatile compounds showed that the beef flavour precursors were positively related to PV, and the off-flavour compounds were highly correlated to AV. Therefore, a moderate oxidation of tallow could be achieved via controlled thermal treatment. [ABSTRACT FROM AUTHOR]

Abstract: Descriptive sensory analysis and gas chromatography–mass spectrometry (GC–MS) analysis were conducted to investigate changes in aroma characteristics of beeflike process flavours (BPFs) prepared from enzymatically hydrolyzed beef (beef base) of different DH (degree of hydrolysis) with other ingredients. Five attributes (beefy, meaty, simulate, mouthful and roasted) were selected to assess BPFs. The results of descriptive sensory analysis confirmed that BPF2 from beef base of moderate DH 29.13% was strongest in beefy, meaty and simulate characteristics; BPF4 and BPF5 from beef base of higher DH (40.43% and 44.22%, respectively) were superior in mouthful and roasted attributes respectively; while BPF0 without beef base gave weaker odour for all attributes. Twenty six compounds from GC–MS were selected as specific compounds to represent beef odour based on their odour-active properties assessed by a detection frequency method of GC–O and correlation of their contents with sensory attributes intensity. Correlation analysis of molecular weight (MW) of peptides, odour-active compounds and sensory attributes through partial least squares regression (PLSR) further explained that beef base with DH of 29.13% was a desirable precursor for imparting aroma characteristics of beeflike process flavour. [ABSTRACT FROM AUTHOR]

Abstract: Partial least squares regression modeling (PLSR) was used to elucidate the relationship and predictability among the chemical parameters, the GC–MS data and electronic nose responses for controlled oxidation of tallow. Models for predicting chemical parameters changes during controlled oxidation from electronic nose data were estimated by projection of test samples onto calibration models based on PLSR. The results showed that peroxide value (PV) and p-anisidine value (p-AV) were significantly well predicted by the electronic nose responses, whereas acid value (AV) was found fairly well predicted only for mildly oxidized tallow. Overall this study gave evidence of the electronic nose system to be a relevant device for future at- or on-line implementation in oxidation control of tallow for preparing fat flavour. [Copyright &y& Elsevier]

In China, incidences involving pupils suffering health problems caused by synthetic running tracks have attracted the public's attention. However, the existence of known and unknown harmful chemicals in the tracks have not yet been explored. Here, the levels of 16 known harmful ingredients were firstly analyzed in 167 school running tracks. In all samples, the recognized toxic solvents and additives, such as the benzene series, soluble mercury, 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA) and toluene diisocyanate monomer (TDI) were under the limits of detection. In contrast, polycyclic aromatic hydrocarbons (PAHs), phthalates, Short chain chlorinated paraffins (SCCPs) soluble lead, cadmium and chromium were found in 86%, 88%, 46%, 81%, 43% and 83% of the specimens, respectively. The levels, toxicology and distribution of these known chemicals were evaluated. Then, a static-headspace gas chromatography-mass spectrometer (GC-MS) method in full scan mode was employed to screen for unknown volatile chemicals. Three groups of chemicals reflecting different kinds of pollution sources were discovered: new solvents, such as N, N-Dimethylformamide, new additives, such as 2-ethylhexanoic acid, and by-products, such as carbon disulfide. In summary, the existence of potential risk factors in school plastic tracks was revealed through exhaustive testing. Moreover, most of the hazardous components detected have been recently included in a new national standard to improve the safety performance of synthetic running tracks. [ABSTRACT FROM AUTHOR]

Magnetic molecularly imprinted polymers (M-MIPs) were synthesized as the sorbents for extracting hexamethylenetetramine (HMT) from milk samples. Molecular simulations were used to calculate the interaction energies of the template monomers. The physical properties of M-MIPs were characterized. The adsorption isotherms and kinetics were investigated. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was applied to determine the amount of HMT residue in milk samples. In the optimized method, a linear calibration curve was obtained using a matrix-matched standard in the range of 1.0–50.0 μg L −1 . The limit of detection (LOD) and limit of quantification (LOQ) was 0.3 μg kg −1 and 1.0 μg kg −1 , respectively. The relative standard deviation (RSD) of the intra-day assay ranged from 2.6% to 5.2%, while that of the inter-day assay ranged from 3.6% to 11.5%. The recovery of HMT in milk samples ranged from 88.7% to 111.4%. [ABSTRACT FROM AUTHOR]

Naphthalene was used as a model compound in order to study the anaerobic pathway of polycyclic aromatic hydrocarbon degradation. Previously we had determined that carboxylation is an initial step for anaerobic metabolism of naphthalene, but no other intermediate metabolites were identified (Zhang & Young 1997). In the present study we furtherelucidate the pathway with the identification of six novel naphthalene metabolites detected when cultures were fed naphthalene in the presence of its analog 1-fluoronaphthalene. Results from cultures supplemented with either deuterated naphthalene or non-deuterated naphthalene plus [^13C]bicarbonate confirm that the metabolites originated from naphthalene. Three of these metabolites were identified by comparison with the following standards: 2-naphthoic acid (2-NA), 5,6,7,8-tetrahydro-2-naphthoic acid, and decahydro-2-naphthoic acid. The presence of 5,6,7,8-tetrahydro-2-NA as a metabolite of naphthalene degradation indicates that the first reduction reaction occurs at the unsubstituted ring, rather than the carboxylated ring. The overall results suggest that after the initial carboxylation of naphthalene, 2-NA is sequentially reduced to decahydro-2-naphthoic acid through 5 hydrogenation reactions, each of which eliminated one double bond. Incorporation of deuterium atoms from D2O into 5,6,7,8-tetrahydro-2-naphthoic acid suggests that water is the proton source for hydrogenation. [ABSTRACT FROM AUTHOR]

Abstract: Changes in the aroma characteristics of mutton process flavors (MPFs) prepared from sheep bone protein hydrolysates (SBPHs) with different degrees of hydrolysis (DH) were evaluated using gas chromatography–mass spectrometry (GC–MS), gas chromatography–olfactometry (GC–O), and descriptive sensory analysis (DSA). Five attributes (muttony, meaty, roasted, mouthful, and simulate) were selected to assess MPFs. The results of DSA showed a distinct difference among the control sample MPF0 and other MPF samples with added SBPHs for different DHs of almost all sensory attributes. MPF5 (DH 25.92%) was the strongest in the muttony, meaty, and roasted attributes, whereas MPF6 (DH 30.89%) was the strongest in the simulate and roasted attributes. Thirty-six compounds were identified as odor-active compounds for the evaluation of the sensory characteristics of MPFs via GC–MS–O analysis. The results of correlation analysis among odor-active compounds, molecular weight, and DSA further confirmed that the SBPH with a DH range of 25.92–30.89% may be a desirable precursor for the sensory characteristics of MPF. [Copyright &y& Elsevier]

The influence of high temperature modes (cooking in traditional clay stewpot (TS) and cooking in commercial ceramic electrical stewpot (CS)) and low temperature modes (cooking in electrical stewpot with Temperature Modulations, TM 1 -TM 6 ) on chicken broth sensory evaluation and flavor profile was studied. Sensory evaluation results showed that chicken broth processed using TM 1 had the best flavor with higher chicken meat-like and lower off-flavor scores. Gas chromatography-mass spectrometry (GC-MS) and GC-MS/olfactometry (GC-MS/O) results revealed that the TM 1 samples had the most abundant odorants. The umami-taste components from TM 1 samples such as umami free amino acids and inosine 5′-monophosphate (IMP) had the highest amount, 20.0 ± 0.10 mg/g chicken broth and 17.19 ± 0.58 μg/g chicken broth respectively. The relationship between sensory evaluation and odor-active compounds were evaluated by Partial Least Squares Regression (PLSR), and the PLSR analysis indicated that heptanal, benzaldehyde, (Z)-2-decenal, (E,E)-2,4-decadienal, 1-pentanol, 2-undecanone, 2-pentyl-furan and one unknown compound were significantly and positively correlated with chicken meat-like note. Whereas, fatty aroma were significantly and positively correlated with octanal, (E,E)-2,4-decadienal and 1-pentanol. (E,E)-2,4-Decadienal and 2-undecanone had a significant and negative correlation with off-flavor attribute. [ABSTRACT FROM AUTHOR]