Analysis of Quality Changes of Platycladi Semen Before and After Deterioration Based on HS-SPME/GC-MS and Electronic Sensory Technology / 中国实验方剂学杂志

ObjectiveTo analyze the quality changes of Platycladi Semen before and after the deterioration of moth-eaten and rancidity during storage. MethodFour types samples of Platycladi Semen， including normal， moth-eaten， oxidative rancidity and hydrolytic rancidity， were determined for volatile components， odor， and taste based on headspace solid phase microextraction/gas chromatography-mass spectrometry （HS-SPME/GC-MS） and electronic sensory techniques such as electronic nose and electronic tongue. Volatile components were identified by searching the database and manual comparison， the odor and taste were determined by the response values of the electronic nose and electronic tongue sensors， and the difference between samples before and after deterioration was studied by multivariate statistical analysis. ResultA total of 85 compounds were identified in Platycladi Semen samples. Compared with the normal samples， the number of volatile compounds in samples after hydrolytic rancidity decreased by 5， the number of volatile compounds in samples after moth-eaten and oxidative rancidity increased by 1 and 21， respectively. Aldehydes and acids accounted for majority of types. Among them， the contents of N-hexanoic acid， hexanal and propionic acid in the samples of oxidative rancidity reached 11.49%， 10.21% and 7.52%， which became the key indicators of rancidity. There was significant variance among the odor components corresponding to W1W， W2W and W1S sensors by electronic nose analysis. It was indicated that the value of sourness in deteriorated samples generally increased by mean of electronic tongue analysis. Compared with normal samples， the moth-eaten samples had changed slightly and rancidity samples had changed significantly especially oxidative rancidity samples of volatile components， odor and taste by multivariate statistical analysis. ConclusionIn terms of Platycladi Semen， the oxidative rancidity caused by nature storage for 12 months has the greatest impact on the quality. Therefore， it should be mainly to prevent oxidative rancidity to ensure the quality of Platycladi Semen.

Comparison on Changes of Volatile Components in Gecko Before and After Processing by HS-SPME-GC-MS / 中国实验方剂学杂志

ObjectiveOn the basis of sensory evaluation， the changes of volatile components in gecko before and after processing were compared， and the odor correction effect of different processing methods of gecko was discussed. MethodRaw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko were prepared， and 10 odor assessors were invited to evaluate the 6 samples in turn by sensory evaluation. Headspace solid-phase microextraction-gas chromatography-mass spectrometry （HS-SPME-GC-MS） and relative odor activity value （ROAV） were used to analyze the key odor components， and multivariate statistical methods were used to analyze the difference of volatile components between raw and processed products of gecko. Taking water-soluble extract and protein contents as internal indicators， sensory evaluation score and content ranking of differential components as external indicators， and assigning a weight of 0.25 to them respectively， the comprehensive scores of raw products and processed products of gecko were calculated to evaluate the odor correction effect of each processing method. ResultThe average sensory evaluation scores of the raw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko were 1.6， 5.2， 6.2， 6.1， 7.2 and 8.0， respectively. ROAV results showed that key components affecting odor of gecko were 2-ethyl-3，5-dimethylpyrazine， isovaleraldehyde， trimethylamine， 1-octen-3-ol， n-octanal， nonanal， 2-methylnaphthalene， γ-octanolide， 2-heptanone and phenol. Principal component analysis （PCA） significantly distinguished raw products from processed products. Orthogonal partial least squares-discriminant analysis （OPLS-DA） results showed that there were 16， 13， 16， 16， 16 differential components between raw products， fried yellow products， vinegar processed products， wine processed products， talcum powder scalding products and white wine sprayed products after scalding talcum powder of gecko. Among these differential components， there were 4 common components， namely， the contents of different odor components （2-methylnaphthalene and 2-ethyl-p-xylene） decreased， while the contents of different flavor components （2-decanone and 2，3，5-trimethylpyrazine） increased. The comprehensive scoring results showed that the odor correction effect of each processed products was in the order of talcum powder scalding products>wine processed products>vinegar processed products>fried yellow products>white wine sprayed products after scalding talcum powder. ConclusionTalcum powder scalding is a better method to improve the odor of gecko， and it can provide an experimental basis for the processing of gecko to correct the odor.

Molecular Mechanism of Selective Binding of Pharmacodynamic Active BVOCs Substance Group with Bovine β-Lactoglobulin / 中国生物化学与分子生物学报

Headspace-solid phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) were used to analyze the interaction between the β-lactoglobulin (β-LG) and the botany volatile organic compounds (BVOCs) from pomelo peel to screen out the pharmacodynamic active BVOCs substance group. The selective binding effect between β-LG and BVOCs was analyzed by quantitative recovery of BVOCs, and the binding parameters were calculated. Then, the molecular model of BVOCs binding with β-LG was established by molecular docking and spectroscopic method, and the molecular mechanism of interaction between pharmacodynamic active BVOCs and β-LG was discussed from the perspective of omics. The results showed that dipentene (Dt), linalylacetate (La) and nootkatone (Nt) of BVOCs were selected by HS-SPME/GC-MS by the interaction of β-LG and BVOCs substance group. Parameter calculation showed that β-LG had the strongest affinity with Nt, but the binding force was not strong, and the affinity for La was the weakest. The affinity of β-LG to Dt was weak, but the binding force was the strongest, with a binding rate of 54. 66%, indicating that the selective binding strength of β-LG with the pharmacodynamic active BVOCs depended on the chemical structure of BVOCs molecules. The β-LG preferred to bind to the aldehyde and ketone BVOCs molecules containing carbonyl oxygen structure. The molecular model of β-LG and BVOCs group (Dt, La, Nt) was established to evaluate the binding position of BVOCs group (Dt, La, Nt) on β-LG. The loosening, extension and conformational change of β-LG secondary structure caused by the introduction of BVOCs are the result of van der Waals force, hydro-phobicity and hydrogen bonding. This study provides a new method for screening pharmacodynamic active BVOCs from the perspective of whole substance group of BVOCs, and provides a useful reference for investigating the binding mechanism between pharmacodynamic active BVOCs and functional protein molecules from the perspective of omics.

Optimization of processing methods for deodorizing Periplaneta americana based on subjective and objective smell evaluation combined with analysis of volatile components / 中草药

Objective: To screen a processing method suitable for deodorizing of Periplaneta americana (PA) through subjective and objective evaluation combined with changes in volatile components, and explore the mechanism of deodorization. Methods: Raw, vinegar-processed, wine-processed, wheat bran-processed products of PA were prepared respectively. Volunteer sensory evaluation combined with electronic nose system was used to evaluate the odor difference between raw and processed products to screen a better processed product. HS-SPME-GC-MS and ROAV were used to analyze the key odorous components of PA. The peak area normalization method combined with multivariate statistical analysis were used to analyze the difference of volatile components between raw and processed products to explore the mechanism of processing. Results|| Volunteer scores showed that the average scores of raw, vinegar-processed, wine-processed, wheat bran-processed products were 3.38, 1.25, 2.88, and 3.04, respectively. The results of the electronic nose showed that the Euclidean distance between the raw and vinegar-processed, wine-processed, wheat bran-processed products were 7.34, 3.77 and 1.60, respectively, but the direction of scatter of vinegar-processed product was opposite to that of wine-processed product and wheat bran-processed product, suggesting that the mechanism of deodorization may be different. Vinegar processing was determined as the optimum method for deodorizing by comprehensive analysis of subjective and objective evaluation data. The key odor components of PA were 3-methyl butanal, hexanal, nonyl aldehyde, heptaldehyde, decyl aldehyde, phenyl acetaldehyde, (E,E)-2,4-nonadienal, 2-pentylfuran, (+)-limonene, and myristic aldehyde. The PCA result of volatile components showed that four kinds of processed products can be clearly distinguished, and there were differences in volatile components and content. There were seven differential chemical components between raw and vinegar-processed products, including hexanal, palmitic acid, oleic acid, acetic acid, ethyl oleate, ethyl palmitate, and ethyl linoleate. The content of vinegar-processed products was lower than that of raw products, especially the key odorous component hexanal. Conclusion: The vinegar processing is a better method to improve the odor of PA, and its mechanism may be associated with reducing odorous components such as hexanal.

Multivariate optimization of a HS-SPME/GC-MS technique for the characterization of volatile compounds present in Hedeoma multiflorum Benth / Optimización Multivariada de una técnica HS-SPME/GC para la caracterización de los compuestos volátiles presentes en Hedeoma multiflorum Benth

The aim of the present work was to optimize the main experimental variables of a procedure using HS-SPME/GC-MS as the analytical methodology to establish the profile of the volatile compounds present in aerial parts of Hedeoma multiflorum Benth. The influence of the type of fiber, equilibrium time, extraction time and extraction temperature on the composition of the volatile compounds was determined using response surface methodology (RSM), and the parameters of the models were corroborated by multiple linear regressions. The results showed that the regression models generated adequately explained the data variation and represented the relationships between the parameters and their responses. The optimal analysis conditions from the contour plots were established (DVB/CAR/PDMS fiber, with a 10 min equilibrium time, 10 min extraction time, and 40°C). Under these conditions, 41 volatile components in the whole plant were determined, which represents more than those reported using hydrodistillation.

El objetivo del presente trabajo fue optimizar las principales variables experimentales de un procedimiento HS-SPME/GC para establecer el perfil de compuestos volátiles presentes en la parte aérea de Hedeoma multiflorum Benth. Se determinó la influencia de las variables tipo de fibra, tiempo de equilibrio, tiempo de extracción y temperatura de extracción sobre la composición de los volátiles, utilizando una met odología de superficie de respuesta (RSM) y los parámetros del modelo se corroboraron por regresión lineal múltiple. Los resultados demostraron que los modelos de regresión generados explican adecuadamente la variación de los datos y representaron significativamente las relaciones reales entre los parámetros y sus respuestas. Las condiciones óptimas de análisis fueron establecidas (DVB/CAR/PDMS, con un tiempo de equilibrio de 10 minutos, un tiempo de extracción de 10 minutos y trabajando a 40°C). Utilizando esta metodología, se determinaron 41 componentes volátiles en planta entera, más que los reportados mediante hidrodestilación.

Characteristics Analysis for Volatile Compounds of 18 Heat-Clearing Herbs / 中国实验方剂学杂志

Objective: Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the characteristic volatile compounds from 18 heat-clearing herbs. Method: HS-SPME was used to extract the volatile components from different heat-clearing herbs,and the chemical compositions were analyzed by GC-MS. The GC was performed at the injector temperature of 250℃,the high-purity helium was used as the carrier gas at a constant column flow of 1.0 mL·min-1 with no split sampling. The solvent delay time was 3 min. Mass spectrum conditions included electron bombardment ion source,electron bombardment energy of 70 eV,ion source temperature of 230℃,quadrupoles temperature of 150℃,and scanning range of m/z 29-370.The volatile components were confirmed according to NIST2013 database,and the relative content percentage of each component was calculated by peak area normalization method. PCA was used to detect clustering and discuss the characteristics of volatile compounds of 18 heat-clearing herbs. Result: A total of 328 volatile compounds were detected in 18 heat-clearing herbs,including alkanes,unsaturated hydrocarbon,alcohols,aldehyde,ketones,esters,furan and other unknown compounds. The number and relative content of volatile components in different heat-clearing herbs varied dramatically. Several important characteristic volatile compounds,such as l-camphor,torreyol,caryophyllene oxide,globulol and 2,4-cycloheptadien-1-one,2,6,6-trimethyl,were detected in the 18 heat-clearing herbs by principal component analysis. Conclusion: Heat-clearing herbs contains rich volatile components,which are the main contributors to the formation of unique aroma of herbs,as well as the main active substances.

Analysis and identification of volatile components of different parts of Clausena lansium in Hainan by HS-SPME-GC-MS / 中草药

Objective A headspace-solid phase microextraction-gas chromatography-mass spectrometry method (HS-SPME-GC-MS) was adopted for analyzing the volatile components of different parts of Clausena lansium in Hainan Province. Methods Five different fibers were investigated and optimized. Other five experimental parameters such as volume of water, extraction temperature, equilibrium time, extraction time, and salt concentration had been evaluated and optimized by means of the orthogonal design with L16(45) table. Finally, the volatile components of C. lansium leaves, pericarps, and seeds in Hainan were analyzed and identified by GC-MS combined with retention index (RI). Results The optimum extraction conditions were as follows: a 50/30 μm DVB/CAR/PDMS fiber, 10 mg sample powders, 2.0 mL water, 0.2 g NaCl, extraction temperature 80 ℃, equilibrium time 30 min, extraction time 60 min. A total of 83 chemical components were identified from leaves, 96 from pericarps, and 106 from seeds, representing the relative contents of 95.24%, 92.15%, and 95.92% of the total composition. The highest contents were sesquiterpenes in all of the parts, but there were obviously different both in components and contents. Conclusion The HS-SPME-GC-MS method is rapid and sensitive, with a small sample size, without any organic solvents. GC-MS combined with RI has improved the accuracy of analysis and identification. The results may provide experimental basis for further exploitation of C. lansium in Hainan. This method can be used to perform enrichment analysis of the components with high-boiling point and micro-components, which can comprehensively and scientifically characterize and evaluate the quality of Chinese materia medica.