Difference in volatile profile between pericarp tissue and locular gel in tomato fruit

Aroma, a complex mixture of volatile compounds, plays an important role in the perception and acceptability of tomato products by consumers. Numerous studies have reported volatile profiles in tomatoes based on measurement of the whole fruit or pericarp tissue, however, little is understood regarding the volatile compositions in the inner tissues. The objective of this study was to investigate the differences in volatile profile between pericarp tissue and Iocular gel in tomato fruit. Based on HS-SPME-GC-MS analysis, totally 42 volatile compounds were detected in FL 47 and Tasti-Lee tomato fruits. Regardless of cultivars, a substantial higher concentration of total volatile compounds was observed in pericarp than that in/ocular gel, associated with higher levels of aldehydes, hydrocarbons, and nitrogen compounds. Pericarp tissue possessed higher levels of cis-3-hexenal, hexanal, heptanal, octanal, nonanal, cymene, terpinolene, undecane, dodecane, 2-phenylethanol, 6-methyl-5-hepten-2-one, 2-methylbutyl acetate, 1-nitro-pentane, and 1-nitro-2-phenylethane, while the abundances of 2-methylpropanal, butanal, 2-methylbutanal, 2-methyl-2-butenal, 2-methylpropanol, 3-methylbutanol, 2-methylbutanol, and 2-butanone were higher in Iocular gel. Principal component analysis （PCA） and cluster analysis using GC-MS and electronic nose （E-nose） data discriminated the two tissues.

Volatile profile analysis and quality prediction of Longjing tea(Camellia sinensis) by HS-SPME/GC-MS

This study aimed to analyze the volatile chemical profile of Longjing tea, and further develop a prediction model for aroma quality of Longjing tea based on potent odorants. A total of 21 Longjing samples were analyzed by headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS).Pearson's linear correlation analysis and partial least square (PLS) regression were applied to investigate the relationship between sensory aroma scores and the volatile compounds. Results showed that 60 volatile compound scould be commonly detected in this famous green tea. Terpenes and esters were two major groups characterized,representing 33.89% and 15.53% of the total peak area respectively. Ten compounds were determined to contribute significantly to the perceived aroma quality of Longjing tea, especially linalool (0.701), nonanal (0.738), (Z)-3-hexenyl hexanoate (-0.785), and β-ionone (-0.763). On the basis of these 10 compounds, a model (correlation coefficient of89.4% and cross-validated correlation coefficient of 80.4%) was constructed to predict the aroma quality of Longjingtea. Summarily, this study has provided a novel option for quality prediction of green tea based on HS-SPME/GC-MStechnique.

Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration：A laboratory test

Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons（VCHs）. Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures（silty,clayey, and sandy soils） along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform（TCM） and trichloroethylene（TCE）. Mechanical soil aeration was effective for remediating VCHs（removal efficiency 〉 98%）. The volatilization process was described by an exponential kinetic function.In the early stage of treatment（0–7 hr）, rapid contaminant volatilization followed a pseudofirst order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8 hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner.

Metagenomics and volatile profile of Turkish artisanal Tulum cheese microbiota

Turkish artisanal Tulum cheese is a traditional raw milk cheese and starter cultures are not used for ripening process.In this study,16S rRNA amplicon-based sequencing approach was used for determining bacterial diversity in Tulum cheeses.The volatile organic compound(VOC)profile which contributes to sensory properties of the cheeses was determined via solid-phase microextraction combined with gas chromatography-mass spectrometry(GC-MS/SPME)and correlated with the microbiota.In Tulum cheese samples,Lactobacillaceae(30,71%)phylum widely varied but Streptococcaceae(59,86%)was dominant.It mainly belongs to the four dominant genera of lactic acid bacteria(LAB)and includes Lactobacillus,Lactococcus,Streptococcus and Pediococcus.The bacterial diversity of TC5 sample was much higher than that of other samples.Moreover,several species of non-starter LAB were frequently detected.A total of 36 volatile compounds were identified including hydrocarbons(3),acids(13),alcohols(5),ketones(3),aldehydes(3),esters(8)and miscellaneous compound(1).Pentadecanoic acid,octadecanoic acid,tetradecanoic acid,octanoic acid,hexanoic acid were determined to be dominant in all cheese samples and to be related to microbial flora.Also,the sensory profiles of the samples were examined.The most popular TC6 did not contain 2-butanone and hexanal from the volatile organic compound(VOC)values,while in the most unpopular TC3,2-butanone(7.73%)and hexanal(5.95%)were found to be the highest.The outcome of this study will contribute to literature on bacterial diversity and aromatic profile of Tulum cheese which should be investigated in order to improve quality and safety.