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Metabolomics analysis was conducted using gas chromatography-mass spectrometry (GC-MS) data, employing principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Two hundred samples of purple-skinned garlic from five regions (Yunnan, Shandong, Henan, Anhui, and Jiangsu) were analyzed. Three preprocessing methods encompassing maximum-minimum normalization (MMS), standardization of standard deviation (SS), and standard normal variate transform (SNV) were used. Five machine learning models including random forest (RF), support vector machine (SVM), XGBoost, convolutional neural network (CNN), and long short-term memory neural network (LSTM) were utilized to classify and discriminate the origin of garlic. The analysis revealed 66 metabolites screened across garlic samples from different origins, with 12 differential metabolites identified through PLS-DA analysis. These metabolites were associated with 6 metabolic pathways: valine, leucine, and isoleucine biosynthesis, galactose metabolism, cyanoamino acid metabolism, glyoxylate and dicarboxylic acid metabolism, glycine, serine, and threonine metabolism, D-amino acid metabolism. Among the five machine learning models, LSTM exhibited the best performance, achieving 100% accuracy on the test set across three preprocessing methods. This study based on the combination of metabolomics and LSTM, a type of machine learning, demonstrates high accuracy and reliability in identifying the origin of garlic, providing a reliable technical means for tracing the source of garlic products.

To evaluate the effects of long-term frozen storage on the flavor quality of Rosa roxburghii juice, sensory evaluation, electronic nose, and headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) were utilized to analyze the dynamic changes of sensory and aroma characteristics of Rosa roxburghii juice at −20 ℃ for various storage times(0, 2, 4, 6, 8 M). The results revealed the identification of a total of 127 volatile compounds, the majority of which were alcohols (31), hydrocarbons (34), and esters (24). The contents of 1-hexanol, (Z)-3-hexen-1-ol, 1-octene-3-ol, linalool, 1-octanol, α-copaene, ethyl hexanoate, ethyl octanoate, and methyl eugenol decreased over time, indicating that the fragrance of green grass, fruit, and flowers may diminish over time. The concentration of nonanal increased substantially (P

In this experiment, five different parts of beef were selected to make boletus beef sauce, namely beef hind leg (BHL), beef shoulder (BS), beef knuckle (BK), beef brisket (BB), and beef tendon (BT), and the effects of different beef parts on the quality and volatile aroma components of spicy beef boletus sauce were investigated. The boletus beef sauce made from BB reported the highest sensory score of 87.4. In terms of texture, beef sauce made from BB exhibited the best quality, with hardness, elasticity, gumminess, and chewiness values of 14.01 N, 4.71 mm, 3.22 N, and 15.30 mJ, respectively. Significant differences (P1. In summary, the BB was proven to be the best raw material in making spicy beef boletus sauce. These research findings provide a theoretical basis and data reference for the future cooking process and flavor characteristics of beef sauce.

In order to investigate the differences in volatile substances of bighead carp (Aristichthys nobilis) meat from various habitats, gas chromatography-mass spectrometry (GC-MS) was employed to detect and compare the volatile substances of bighead carp meat from five different habitats, including Hongmen Reservoir, Junshan Lake, Zhelin Lake, Datang Reservoir, and Nanxin culture pond. The results showed that a total of 56 volatile substances were detected in bighead carp meat from five habitats, including 12 aldehydes, 8 ketones, 15 alcohols, 8 hydrocarbons, 13 aromatic and other substances. Moreover, hexyl aldehyde, heptyl aldehyde, nonyl aldehyde, n-hexyl alcohol, 1-octene-3-alcohol, and heptadecane were common chemicals found in bighead carp meat of all habitats. Utilizing relative odor activity value (ROAV), aldehydes, alcohols, and phenols were identified as the key odor substances in bighead carp meat. Cluster analysis (CA) and principal component analysis (PCA) results showed the cumulative contribution rate of PC1 and PC2 reached 73.5%. Moreover, the volatile substance composition and odor of bighead carp meat from macro-aquatic habitats were similar. Meanwhile, the odor was significantly better than that of bighead carp meat from high-density aquaculture habitats. On the whole, significant differences were observed in the composition, content of volatile compounds, and key odor substances among bighead carp meat from different habitats (P

To explore the quality and material basis of Shoumei white tea from different varieties of tea trees, in this study, Shoumei white tea made from the raw materials of Fu'an Da Bai (FA), Fuding Da Hao (FD), Meizhan (MZ) and Fengqing Da Ye Zhong (FQ) were analyzed for their quality using sensory evaluation, high performance liquid chromatography (HPLC), headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Orthogonal partial least squares discriminant analysis (OPLS-DA) and its permutation test were used to distinguish the differences among the samples, and variables were selected based on the variable importance in projection (VIP) values and P-values. The results indicated that there were differences in both sensory evaluation and physicochemical properties among the white teas processed from the four varieties of tea trees. Each of the Shoumei white teas from the four varieties of tea trees exhibited good sensory qualities and distinct characteristics. The water extract content of the different Shoumei white teas ranged from 45.48% to 46.89%, the tea polyphenol content ranged from 16.79% to 19.96%, the caffeine content ranged from 41.34 to 56.61 mg/g, the total theaflavin content ranged from 3.31 to 8.22 mg/g, the total catechin content ranged from 143.90 to 165.62 mg/g, the non-esterified catechin content ranged from 21.55 to 36.01 mg/g, the esterified catechin content ranged from 114.14 to 134.16 mg/g, and the total free amino acid content ranged from 30.35 to 38.31 mg/g. Furthermore, differences in the content of non-volatile compounds were observed among the different tea samples. A total of 57 volatile compounds were detected in the four tea samples, with a total concentration ranging from 121.63 to 203.43 μg/g. Among them, alcohols and aldehydes accounted for the majority. Significant differences were observed among the tea samples in terms of the aroma profile, types, and concentrations of volatile compounds. OPLS-DA based on 93 compounds from the four tea samples was employed to effectively differentiate between the tea samples and identify 56 differentiating compounds (VIP>1 and P

Five kinds of commercially available sour fish sauce were taken as the research object to clarify their quality and flavor characteristics. The physicochemical and nutritional indexes, free amino acids, and volatile components were analyzed. The results showed that the moisture, ash, total acid, amino acid nitrogen, reducing sugar, protein, vitamin C and fat contents in the five kinds of sour fish sauce were significantly different (P

To investigate the effect of drying methods on the volatile flavor substances of Toona sinensis, the volatile components of vacuum freeze-dried, heat pump-dried, hot air-dried, and microwave vacuum-dried Toona sinensis samples were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) coupled with relative odor activity values, and the differences of volatile components among samples were further explored by combining the stoichiometric principal component analysis and partial least square discriminant analysis. The results showed that 78 peaks were detected and 59 compounds were identified by GC-IMS. 94 kinds of volatile compounds were identified by GC-MS, and the main volatile components were sulfides, olefins and aldehydes. The content of total volatile compounds was significantly reduced after drying. The key aroma compounds in Toona sinensis samples were identified by ROAV method, such as (E,Z)-di-1-propenyldisulfide, 2-mercapto-3,4-dimethyl-2,3-dihydrothiophene, hexanal, 2-hexenal and eugenol. The PCA and PLS-DA results showed that the samples with different drying methods were not only clearly separated from the raw samples, but also significantly different from each other. The raw samples and vacuum freeze-dried samples were grouped, and the other three dried Toona sinensis samples were grouped. According to the variable importance in projection score, a total of 10 (VIP>1) labeled volatile compounds were selected. The drying method had significant effect on the flavor characteristics of Toona sinensis, and the vacuum freeze-dried group was the closest to the raw sample, while heat pump-drying was the most suitable dehydration method for Toona sinensis, considering the practical application. This study provides some theoretical references for flavor quality control in the thermal processing process.

Meat products contain a large number of flavor compounds (mainly aroma and taste compounds), but only a few of them affect the final flavor of the product. How to isolate and identify the key aroma or taste compounds from a large number of flavor compounds is a hot issue in the research on the flavor and quality of meat products. Molecular sensory science is a systematic science that integrates analytical chemistry, food sensory evaluation and other disciplines. Its research methods can solve the above problems well. In this paper, the application of molecular sensory science in meat products and the advantages and disadvantages of different analytical techniques are summarized. Meanwhile, the evaluation methods of molecular sensory science are expounded, and the importance of recombination and deletion experiments to further confirm the key flavor components are highlighted. This review provides a certain practical reference and theoretical basis for the research in the field of meat flavor and sensory technology innovation.

Investigation of the aroma differences among different kinds of soy sauces is beneficial for controlling their flavor quality and processing improvement from the perspectives of raw materials and brewing techniques. The aroma compounds in ten premium soy sauces (CB, HT1, HT2, LH, LJJ1, LJJ2, QH, XH1, XH2, WZ) were qualitative and quantitative analyzed by solid phase extraction and solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS). The contributions of aroma compounds to the aroma characteristics of premium soy sauce was determined by sensory evaluation, calculation of aroma activity value (OAV) and partial least squares regression analysis (PLSR). A total of 86 volatile compounds were identified in 10 premium soy sauces, 44 of them were both detected in 10 soy sauce. The 30 aroma compounds with OAV≥1 were detected, the 5-ethyl-4-hydroxy-2-methyl-3(2H)-furanone showed the highest OAV (373~4698), followed by 4-methoxy-2,5-dimethyl-3(2H)-furanone (0~1473). WZ soy sauce had a strong smoky aroma due to the highest variety of phenolic and ketone compounds. The overall aroma profile of CB soy sauce was the weakest with the lowest concentration of ethanol (25.775 μg/L), but the highest content of pyrazine compounds (182.796 μg/L), of which 2,6-dimethylpyrazine was 66.256 μg/L. XH1 soy sauce had a strong sauce aroma and alcoholic notes, due to the highest ethanol content (147.257 μg/L) and higher phenolic content, for example the concentration of 4-ethyl-2-methoxyphenol (18240.479 μg/L) was the highest. XH2 soy sauce had a strong malty aroma. The content of 2-methyl-1-propanol (51.223 μg/L) and 2,3-butanediol (57921.798 μg/L) in LH soy sauce was the highest among others. The content of 1-octen-3-ol (61.219 μg/L) in HT1 soy sauce was the highest. Combination of OAV and PLSR analysis confirmed the ethyl acetate, 3-hydroxy-2-butanone, 2,3-butanediol, 3-ethyl-2,5-dimethylpyrazine, 4-methoxy-2,5-dimethyl-3(2H)-furanone, 4-ethylguaiacol and 4-ethylphenol were the key aroma-active components that contribute to the aroma differences among 10 kinds of premium soy sauce.

Taking Jinggang pomelo peel essential oil (JPPEO) as the research object, two methods of steam distillation and low-temperature continuous phase transition were used for extraction. Orthogonal test was used to study the effects of extraction temperature, extraction pressure and extraction time on the yield of essential oil of Jinggang pomelo peel. At the same time, the physicochemical properties and chemical composition of essential oil were analysed. The results showed that the optimum extraction process of essential oil extracted by low-temperature continuous phase transition （L-JPPEO）was obtained as follows: particle size 30 mesh, extraction temperature 55 ℃, extraction pressure 0.6 MPa, extraction time 60 min, and the analysis temperature 70 ℃. At this time, the extraction rate was 10.99‰, the yield of L-JPPEO was 2.88 times higher than that extracted by steam distillation (H-JPPEO). The physicochemical properties of the essential oil of JPPEO extracted by low-temperature continuous phase transition showed that the content of unsaturated fat acid was higher, the content of free fatty acid was lower, the content of esters was lower. FTIR identified L-JPPEO and H-JPPEO containing terpenes, alcohols, phenols, aldehydes and carbonyl compounds. GC-MS technology identified 23 and 32 compounds from H-JPPEO and L-JPPEO samples, respectively. Among which 15 compounds were detected in both essential oils, the relative content of D-limonene was the highest, the relative content in L-JPPEO was 4.75±0.16 μg/mL, while the relative content in H-JPPEO was 640.93±44.47 μg/mL. HS-GC-IMS identified 71 compounds from both extraction methods of essential oils. Compared with steam distillation, low-temperature continuous phase change extraction technology extracted more terpenes (45.75%), ketones (7.68%), esters (15.85%), and acids (5.62%).

The composition and content of fatty acids in edible cassava flour not only affect its shelf life but also serve as important indicators for evaluating the nutritional quality of cassava flour. In this experiment, edible cassava flour was used as the sample. By optimizing the fatty acid methyl esterification method and gas chromatography conditions, a qualitative and quantitative detection method for fatty acids in edible cassava flour was established. The fatty acid composition in edible cassava flour of different varieties (strains) and different storage times was analyzed and detected. The results showed that gas chromatography could accurately analyze and quantify various fatty acids in edible cassava flour. There was a good linear relationship between the concentrations of palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid in the ranges of 20.0~1000.0, 4.0~400.0, 30.0~1500.0, 10.0~500.0 and 2.0~100.0 μg/mL, respectively, with coefficient of determination (R2) ranging from 0.9992 to 0.9999. The relative standard deviations (RSDs) of sample repeatability ranged from 0.5% to 3.2%. The RSDs of concentration changes after 24 hours of storage at room temperature ranged from 0.7% to 1.1%. The average recovery rates of the five fatty acids in the samples ranged from 88.0% to 105.4%, with average recovery rate RSD ranging from 3.4% to 10.4%, indicating good sample stability, method repeatability, and accuracy. The cassava flour prepared from different edible cassava varieties mainly contained palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. There were significant differences in fatty acid content among different varieties, and the proportions of the five cassava flour fatty acids (SFA/MUFA/PUFA) were 1:(0.91~1.35):(0.12~0.39). Among them, the content of palmitic acid, oleic acid, linoleic acid, and linolenic acid in 'Huanan 9' cassava flour was significantly higher than other varieties (P

In order to study the mechanism of protease which influences on the flavor of soymilk, different kinds and concentrations of protease (papain, 15000, 30000, 45000, 60000 and 75000 U/L, aminopeptidase, 500, 1000, 1500, 2000 and 2500 U/L, flavor protease, 100, 150, 200, 250 and 300 U/L, alkaline protease, 500, 1500, 2500, 3500 and 4500 U/L) were added to the soymilk made by automatic soymilk maker. Sensory evaluation was carried out on the soymilk after heating. The content and difference of polypeptide and amino acid nitrogen in the soymilk after enzymatic hydrolysis and heating were determined, and the correlation between them and sensory flavor indexes was analyzed. The volatile flavor components of soymilk were analyzed by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS). The results showed that in the blank control group prepared by automatic soymilk maker without protease, the unpleasant beany odor and pleasant bean aroma of soymilk after heating were both lighter than those prepared by traditional method named the raw bean control group, while the contents of polypeptide and amino acid nitrogen showed reductions of 37.98% and 25.78% as compared to the raw bean control group, respectively. The sensory evaluation was carried out after adding different proteases to the soymilk prepared by automatic soymilk maker. The results showed that the soymilk added with 250 U/L flavor protease had the highest sensory score, which increased by 118.41% compared with the blank control group. In all groups added with proteases, the sensory score was significantly higher (P

The volatile substances among Malus toringoides (Rehd.) Hughes black tea，green tea and Kang brick tea were detected by electronic nose (E-nose), trap head space-gas chromatography-mass spectrometry (HS Trap GC-MS) and the differences of the volatile substances were analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA), relative odor activity value (ROAV) and differential thermography in order to explore the odor differences of Malus toringoides (Rehd.) Hughes teas with three different processes. Result showed that E-nose could effectively distinguish three kinds of Malus toringoides (Rehd.) Hughes teas, and the prediction ability of the model established by E-nose combined with OPLS-DA was 95.70%. GC-MS analysis showed that aldehydes, esters and hydrocarbons were the main volatile substances, while alcohols were the main common volatile substances of black tea and green tea. The differences in the contents of aldehydes, esters, hydrocarbons and alcohols account for the variations in the aroma of Malus toringoides (Rehd.) Hughes teas produced by different processes. ROAV value combined with aroma type analysis showed that the volatile components of fruit aroma had a relatively large contribution to the formation of the odor of Malus toringoides (Rehd.). Isovaleraldehyde might be the key aroma substance to Malus toringoides (Rehd.) Hughes teas. Differential thermogram analysis showed that trimethoxyester, isovaleraldehyde and 2-ethylfuran were the main common volatile substances in Malus toringoides (Rehd.) Hughes teas.

In this study, headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to determine the volatile flavor compounds of sundried Ulva spp., including U. prolifera collected from Xiamen (sample X), U. linza collected from Yantai (sample Y) and U. clathrata collected from Ningbo (sample N). A total of 61 volatile compounds including 19 aldehydes, 9 ketones, 6 alcohols, 8 acids, 3 esters, 2 sulfur compounds, and 14 other compounds were detected. The content of sulfur compounds was reaching 40.39%~58.09%. Meanwhile, relative odor activity value (ROAV) and sensory evaluation were employed to identify the aroma active components of Ulva spp.. The results revealed that dimethyl sulfide (onion, garlic, sulfur) and β-ionone (violet, floral) were the key aroma active components of dried Ulva spp.. Besides, dimethyl sulfoxide, 4-methyl-3-penten-2-one, benzaldehyde and 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H)-benzofuranone were the important aroma active components of three Ulva spp.. Among three tested Ulva spp., sample N contained the most abundant volatile compounds especially in aldehydes and ketones, and (E)-2-butenal, (E)-2-octenal, (E)-2,6-nondialdehyde and 1-octene-3-ol were considered as the key volatile substances. Aroma active compounds including 4-ethylbenzaldehyde, (5Z)-1,5-octadiene-3-ol, and 5-methyl furfural were only detected in sample Y, which might correlate to its unique green and fruity flavor. For sample X, the sensory analysis reulst revealed significant fishy smell (P

In this study, gas chromatography-mass spectrometry (GC-MS) was used to detect the volatile substances in the fish flavored and spicy flavored compound condiments made from different brands of Pixian douban, and the effects of different brands of Pixian douban on the volatile flavor substances of the compound condiments were analyzed in combination with chemometrics and sensory properties. The results showed that 63 volatile components were identified in fish-flavored compound seasoning, including 6 alcohols, 5 ethers, 6 aldehydes, 6 acids, 28 terpenoids, 3 ketones, 5 esters and 4 other compounds. A total of 64 volatile components were detected in the samples of spicy compound flavorings, including 6 alcohols, 1 ether, 9 aldehydes, 8 acids, 27 terpenoid hydrocarbons, 1 ketone, 5 esters and 7 others. The study showed that there were significant differences in the effects of different brands of Pixian douban on the flavor of fish flavor and spicy flavor compound seasoning, and the differences in the flavor of fish flavor compound seasoning were mainly reflected in the types and contents of aldehydes, esters and ethers.the products made by Chuanpi, Hengxing and Dandan Douban had a high content of aldehydes, esters and ethers, which played an important role in the formation of fish-flavor flavor. The difference of flavor of spicy compound condiments was mainly reflected in the type and content of aldehydes, the advantage of Chuanlaohui douban to enhance the characteristic flavor of spicy type was reflected in the rich aldehydes.

Ning black tea is one of the earliest congou black teas in China. To investigate the aroma components of Ning black teas, different grades (tribute, special grade and first grade) of Ning black teas were collected and sensorily evaluated. Aroma components were analyzed by stirring bar adsorption extraction (SBSE) combined with gas chromatography-mass spectrometry, and the differential aroma components were screened out via statistical analysis. Finally, partial least squares regression analysis (PLS-RA) was used to identify the key differential aroma components that have an important impact on the aroma quality of different grades of Ning black teas. The sensory evaluation result showed that the overall quality of Ning black tea increased with its grade. In total, 142 volatile components were identified, which were divided into 9 categories, mainly consisting of the esters (41.29%) and alcohols (30.03%). Methyl salicylate (217.44‰), linalool (88.52‰), geraniol (65.54‰), β-ionone (56.07‰), phytol (52.72‰), and phenyleacetaldehyde (41.04‰) amongst others were the main aroma components. A total of 69 volatile components showed extremely significant differences (P

In order to optimize the cooking technology of flowering broad beans, four processing parameters including soaking temperature, soaking time, frying temperature and frying time were selected for single factor and orthogonal optimization experiments, and the indexes of color difference, texture, energy and nutrition, and volatile substances were detected. The results showed that the optimal process for producing flowering broad beans were: Soaking temperature 25 ℃, soaking time 15 h, frying temperature 180 ℃ and frying time 6 min. Color difference characteristics: L* 71.05±1.22, a* 10.59±0.67, b* 29.31±1.46, texture characteristics: Crispness 20.74±1.46 N, hardness 26.67±1.33 N, nutritional label: Each 100 g of flowering broad beans contained 1869.33±0.58 kJ of energy, 18.83±0.40 g of protein, 26.93±0.21 g of fat, 33.40±0.10 g of carbohydrate. The GC-MS test results showed that there were 75 volatile substances in the two groups of samples, mainly benzene and its derivatives, alcohols, olefins, etc, including 37 in the blank group, 40 in the optimal group, and 2 kinds of volatile substances in the two groups. The characteristic substance of the blank group was p-isopropyltoluene, and the characteristic substance of the optimal group was 1-isopropenyl-3-methylbenzene. The GC-IMS test results showed that there were 57 volatile substances in the two groups of samples, mainly alcohols, esters and heterocyclic, etc, including 44 in the blank group, 42 in the optimal group, and 29 kinds of volatile substances in the two groups. After processing, the types and contents of alcohols, aldehydes and ketones decreased in varying degrees, while esters and ethers increased in varying degrees. The results of GC-IMS and GC-MS were consistent. The flowering broad beans under the optimized technology are golden in color, crisp and delicious, and rich in flavor substances.

To compare the effects of different drying methods on the solid spice of sweet potato, the fresh sweet potato was taken as the research object, and infrared drying, freeze drying, microwave vacuum drying and vacuum drying were carried out after baking. The volatile/semi volatile components of the solid spice of sweet potato were analyzed and detected by gas chromatography mass spectrometry (GC-MS), principal component analysis was used to explore the impact of different drying methods on volatile/semi volatile components, and scanning electron microscopy was used to explore the impact of different drying methods by its surface structure. The results showed that the content of volatile/semi-volatile substances in dried sweet potato solid flavor from high to low was vacuum drying, microwave vacuum drying, infrared drying and freeze drying, and the highest content was 128.87 μg/g, the main flavor substances include octyl p-methoxycinnamate, palmitoleic acid, geranyl linalool, 5-hydroxymethylfurfural, (9Z)-octadec-9,17-dialdehyde. Compared with the other three drying methods, the surface structure of vacuum dried solid spice had more water evaporation channels and holes, and the structural density was moderate, which had a positive impact on the adsorption capacity and volatile flavor of solid spice. In conclusion, vacuum drying was applicable to the drying and preparation of sweet potato solid spice, which laid a theoretical foundation for the development and application of sweet potato solid spice.

To promote the application of Leucosceptrum canum honey in food processing and improve its potential development and utilization value, in this study, Leucosceptrum canum honey yogurt was prepared with Leucosceptrum canum honey and cow milk as raw materials. The preparation process of Leucosceptrum canum honey yogurt was optimized based on a single-factor experiment and response surface test. Gas chromatography-mass spectrometer (GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were used to analyze the free fatty acids and volatile flavor components of Leucosceptrum canum honey yogurt. The results showed that the best formula for Leucosceptrum canum honey yogurt was 1.2% Leucosceptrum canum honey, 7% sucrose, and 9 h fermentation time. The sensory score was 87.5±1.3, and the related physical and chemical health indicators of the product met the standard requirements. At the same time, compared with the yogurt without Leucosceptrum canum honey, the content of unsaturated fatty acids in Leucosceptrum canum honey yogurt increased. There were 74 volatile flavor components in Leucosceptrum canum honey yogurt, among which the contents of hydrocarbons and esters were higher. And the relative contents of phenols, esters, and ketones were increased by 4.06%, 1.35%, and 1.35%, respectively, compared with the blank yogurt. The overall flavor quality was improved. The yogurt prepared with Leucosceptrum canum honey and cow milk, had delicate tissue, good stability, and good flavor. The yogurt product was health with certain characteristics.

To illustrate effects of sealed yellowing on the aroma quality of tea samples, sensory evaluation, headspace solid-phase microextraction combined with gas chromatography-mass spectrometry and multivariate statistical analysis were used to study the aroma characteristics and volatile compounds of yellow teas (with sealed yellowing) and control samples (without sealed yellowing) manufactured from three tea varieties. The result showed that yellow teas had sweet flavor compared with control samples. Meanwhile, the total content of volatile components in the yellow tea was 1.09~1.44 times that of the control sample, and the proportion of alcohols and hydrocarbons accounted for 65.88%~76.93%. The result of principal component analysis and hierarchical cluster analysis of volatile compounds indicated that the composition of compounds reflected the difference of aroma characteristics, and then 35 characteristic aroma compounds were screened (P

To find potential brewing ingredients for Luzhou strong-aroma Baijiu, two Baijiu samples were fermented using Glutinous sorghum (GS) and its mixture with Triticum aestivum L. ZN168 (MGZ) in the ratio of 2:8 (w:w), and their flavor substances and harzard components were tested using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that the proteins, polyphenols and anthocyanins contents in GS and MGZ were measured to show no significant difference (P>0.05), while the pectins contents of MGZ were down by 9.7% compared with GS. And compared with GS Baijiu, the total ester contents and the total acid contents of MGZ Baijiu were slumped by 7.9% and rising by 8.3% respectively, but both of them satisfied the national standards of superior Baijiu products in China. Meanwhile, being characteristic of high ethyl hexanoate contents, GS Baijiu and MGZ Baijiu both showed typical flavors of strong-aroma Baijiu. In two Baijiu samples, totally 102 volatile components were detected, identified and quantified, and 26 substances were found to contribute to the formation of flavor differences between the two Baijiu samples, using orthogonal partial least-squares discrimination analysis (OPLS-DA) and odor activity values (OAV) analysis. Compared with GS Baijiu, MGZ Baijiu had higher OAVs of middle- and long-chain fatty acid esters, fatty acids and alcohols, and its methanol and ethyl carbamate contents were fell by 20.6% and 39.9% separately, showing good safety with fill-bodied flavor, rich and mellow taste. These findings suggested that ZN168 could be a potential fermentation material for strong-aroma Chinese Baijiu.

To investigate the effects of crushed water extraction, uncrushed water extraction, crushed alcohol extraction, uncrushed alcohol extraction, pulverized soup post-extraction and unpulverized soup extraction on volatile flavor components of Zanthoxylum bungeanum Maxim. and its ability to confer volatile flavor substances to braised duck neck was studied. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) were used to determine the differences of main volatile flavor components in brine and braised duck neck under different treatment methods. GC-MS results showed that the main aromatic compounds in Zanthoxylum bungeanum Maxim. were alcohols, hydrocarbons, esters and ethers. Water extraction could improve the dissolution of 4-terpineol and other alcohols, and alcohol extraction could improve the dissolution of pyoletene and other substances. Decoction extraction had a better dissolution effect on ethers, and crushing treatment could effectively promote the dissolution of hydrocarbons and esters, and was not conducive to the retention of volatile components of alcohol and ether in the brine. The main substances in braised duck neck were 4-terpenoid and cineole after brine preparation of Zanthoxylum bungeanum Maxim. extract under different treatment methods. Water extraction could significantly promote the retention of eucalyptol and limonene in braised duck neck. Ethanol extraction improved the effect of anethole in duck neck. Whether Zanthoxylum bungeanum Maxim. was crushed or not had no significant effect on the volatile flavor substances assigned to duck neck by the prepared brine. Based on GC-IMS spectrum analysis, it was found that for the extract, only alcohol extraction showed significant differences. Similarly, only alcohol extraction showed significant difference in braised duck neck. The volatile flavour compounds of different treatments for Zanthoxylum bungeanum Maxim. extract and gives braised duck neck ability has a significant effect of volatile flavor substances.

In this study, cellulase-assisted steam distillation was used to extract essential oil from bergamot peel. Based on the single factor analysis of enzymatic hydrolysis pH, enzymatic addition amount, enzymatic hydrolysis temperature and enzymatic hydrolysis time, the extraction process was optimized by using Box-Behnken response surface design method. Moreover, the chemical compositions of the extracted essential oil were analyzed by Gas chromatography-mass Spectrometry (GC-MS). Finally, the antioxidant activities of the essential oil was evaluated by the scavenging rates of ABTS+· and DPPH·. According to the research results, 3.11% yield of essential oil was achieved under the optimal extraction conditions: enzymatic hydrolysis of pH5.2, enzymatic dosage of 0.7%, enzymatic hydrolysis temperature of 52 ℃, and enzymatic hydrolysis time of 2.1 h. A total of 42 compounds were identified from the extracted peel essential oils. Among them, linalool acetate had the highest (14.72%) relative content, followed by d-limonene (14.58%) and linalool (8.89%). Besides, according to the results of antioxidant activity study, the essential oil extracted by this method presented good antioxidant activity in the experimental concentration range, and showed an obvious dose-effect relationship. The scavenging rate of ABTS+· reached 91.20% when the concentration of essential oil was 40 mg/mL; and the scavenging rate of DPPH· reached 93.19% when the concentration of essential oil was 70 mg/mL. Therefore, this optimized process has high yield of essential oil and can be developed as a natural antioxidant.

In this research, the compositional changes of key aroma compounds of ‘Guire No. 82’ mangoes before and after dehydration at green, semi-ripe and fully ripe stages were assessed by gas chromatography-mass spectrometry (GC-MS). The results revealed that the key aroma compounds of fresh fruit in ‘Guire No. 82’, such as β-pinene, 2-carene, β-myrcene, 3-hexene-1-alcohol, etc., possessed the highest content in the green ripening stage, which also suffer a great loss accompanying with the processing, and even not at all for decyl aldehyde. Meanwhile, the content of β-pinene and β-myrcene gradually decreased with the mango ripening, but the content of ethyl caproate and ethyl butyrate increased and reached the middle value at the half-ripe stage, and its content remained the highest after processing. Additionally, the content of ethyl hexanoate, ethyl butyrate and phenethyl alcohol reached the peak value at the full ripening stage, however, the loss of its content after processing was also very obvious, especially for ethyl hexanoate. O-cymene was only detected at the half-ripening stage, which remained after processing. The content of β-ionone was the highest in the half-ripening stage and remained at the highest level after processing. From the analysis of main aroma components, the 14 main aroma components of half-ripe mango did not disappear after processing, and the retention rate of main aroma components (original fruit flavor) reached 100%. Therefore, compared with other ripening stages, the key aroma compounds of mangoes processed into original dried fruit at the half-ripening stage of ‘Guire No. 82’ were better than those of the other two stages.

In order to examine the variation of volatile components of Eucommia ulmoides leaves Fuzhuan tea during the production process, the combination of headspace solid phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) was applied to explore the changes of volatile components of tea products during the production process. The results showed that 152 volatile components were identified in the production process of Eucommia ulmoides leaves Fuzhuan tea. Among these volatile components, the relative contents of acids, esters, ketones, alcohols were high and may be the main volatile components of Eucommia ulmoides leaves Fuzhuan tea during the production process. Principal components analysis (PCA), hierarchical cluster analysis (HCA) and partial least squares discriminant analysis (PLS-DA) were used to effectively distinguish the different processing stages of Eucommia ulmoides leaves Fuzhuan tea. The composition and structure of volatile components, such as acids, alcohols, ketones and esters, altered significantly during the production process of Eucommia ulmoides leaves Fuzhuan tea, whereas the contents of the volatile components with irritant, green, spicy and bad smell volatile components such as propanoic acid, acetic acid and 2-hexenal showed a decreased trend. Moreover, linalool, dodecanoic acid, tetradecanoic acid, hexadecanoic acid ethyl ester, 4-hydroxy-5-methyl-3(2H)-furanone, acetaldehyde and other volatile components with fungus fragrance, woody fragrance, flower fruit fragrance and frankincense presented a increased trend. Based on VIP value, 64 markers of differential volatile components during the production process were identified. For instance, the relative contents of 5-methyl-1H-Indole, dotriacontane and 1-dodecanol in the raw material samples, 3-amino-phenol, oxacyclohexadecan-2-one and 5-hydroxy-3-methyl-1-indanone in the piling fermentation samples, benzoic acid, 2-methoxy-4-vinylphenol and 1-hexen-3-ol in the steam and forming stage samples, 6,10,14-trimethyl-2-penta- decanone, 1H-pyrrole-2-carboxaldehyde and 2-hydroxy-cyclopentadecanone in the 8th day of flowering stage samples, and ethosuximide, 1-methoxy-4-propyl-benzene in the 25th day of flowering stage samples were relatively higher compared with other stages. Therefore, these compounds might be the potential indicators for the assessment of the raw material screening, piling fermentation, steam and forming, different stages of flowering of Eucommia ulmoides leaves Fuzhuan tea. In the finished product, hexadecanoic acid methyl ester，(R)-5,6,7,7a- tetrahydro-4,4,7a-trimethyl-2(4H)-Benzo-furanone, dodecanoic acid, 6,10,14-trimethyl-2-Penta-decanone, β-ionone and other volatile components were relatively higher compared with the content of aromatic volatile components, which might be the main material basis of fragrance of Eucommia ulmoides leaves Fuzhuan tea. The results can provide the material basis for identifying the aroma characteristics and regulating the formation of aroma of Eucommia ulmoides leaves Fuzhuan tea during processing.

Targeted at the aged Fengxiang crude Baijiu stored in Jiuhai, a container for Chinese Baijiu, this paper adopted the gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) to analyze the changes of volatile substances in the Fengxiang Baijiu. The results indicated that 85 compounds were detected by GC-MS, including 41 esters, 10 acids, 17 alcohols, and some compounds with high molecular weight. During storage, the content of esters decreased obviously, that of acids increased, and that of higher fatty acid esters such as ethyl palmitate, ethyl linoleate, elaidic acid ethyl ester, and stearic acid ethyl ester, and phenylethyl alcohol showed a linear growth. In contrast, a total of 47 compounds, dominated by 23 esters and 14 aldehydes and ketones, were identified by GC-IMS, as it was more sensitive to substances with small molecules. It was found that the content of dipropyl sulfide, isopentane, diacetyl, etc., increased with time. The principal component analysis (PCA) of the two techniques showed that there were significant differences between aged crude Baijiu. Combining the above two techniques, a change law of the volatile components in aged Fengxiang crude Baijiu was derived, the content of acids increased, that of esters declined, and that of ethyl palmitate, ethyl linoleate, elaidic acid ethyl ester, stearic acid ethyl ester, phenylethyl alcohol, benzaldehyde, dimethyl sulfide, and lactic acid grew. It was expected that the results of this paper could provide a theoretical basis for the establishment of the aging system of Fengxiang Baijiu.

The drying is an important part of the processing of Ziziphi Spinosae Semen (ZSS) in the producing area and has an important effect on the quality of ZSS. In this study, an integrated 1H nuclear magnetic resonance and gas chromatography-mass spectrometry method was developed to reveal the effects of vacuum drying (VD), freeze-drying (FD), and hot air drying (HAD) method on the chemical composition and antioxidant activity of ZSS. Then the effects of different drying methods on the quality of ZSS were investigated. The results showed that the VD produced high contents of 6 fatty acids (palmitic acid, linoleic acid, oleinic acid, stearic acid, squalene, and γ-tocopherol), 7 amino acids (leucine, isoleucine, valine, alanine, γ-aminobutyric acid, glutamine, and threonine), and 2 carbohydrates (α-glucose and β-glucose), but exhibited weak DPPH radical scavenging activity, ABTS cation radical scavenging activity and FRAP antioxidant activity (FD>VD>HAD). However, FD gave an improved secondary metabolite profile retention, such as jujuboside A, betulinic acid, magnoflorine, and 6ʹʹʹ-feruloylspinosin, thereby resulting in a superior DPPH radical scavenging activity (IC50: 2.82±0.15 mg/mL), ABTS cation radical scavenging activity (IC50: 0.86±0.02 mg/mL) and FRAP antioxidant activity (58.91±2.87 mg VC/g). Thus, FD was a suitable drying method to maximize the product quality retention of ZSS. This study can provide a scientific reference for the establishment of reasonable processing technical specifications of ZSS and provide an experimental basis for improving the quality of ZSS.

In order to explore the quality and flavor differences of traditional homemade chopped peppers from different regions, this study selected traditional homemade chopped peppers from six regions in Hunan as the research object, and determined the differences in organic acids and volatile components by using high performance liquid chromatography and headspace solid phase microextraction-gas chromatography (HS-SPME-GC-MS). The differences in physical and chemical parameters, organic acids and volatile components were compared and analyzed. The results showed that the salinity, acidity, various organic acids and volatile components of the farm chopped peppers in six different regions were significantly different (P

In order to understand the volatile matter information of sun-dried green tea in Menghai County, eight samples of sun-dried green tea in Menghai County were detected by electronic nose and headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The results of electronic nose detection showed that the 8 tea samples could be divided into 4 groups, among which 5 tea samples from Nannuoshan (NN), Xiding (XD), Bulangshan (BL), Gelanghe (GL) and Zhangjiasandui (ZJ) belonged to one group, while Bada (BD), Bulangshan Border (BJ) and Bada Zhanglang (ZL) belonged to one group respectively. Sulfides and hydrocarbons were the main volatile compounds in the sun-dried green tea samples enriched by electronic nose. GC-MS results showed that 55 volatile compounds were detected in 8 sun-dried green tea samples, mainly alcohols (9 kinds), esters (7 kinds), aldehydes (9 kinds), ketones (6 kinds), alkenes (13 kinds), alkanes (5 kinds), heterocyclic (4 kinds). Alcohols had the greatest influence on the relative content of volatile substances in sun-dried green tea, the highest was ZL tea sample (64.02%), and the lowest was BJ tea sample (37.14%), which was mainly manifested in linalool and phytol. There were 19 kinds of volatile substances in 8 sun-dried green tea samples, and 10 kinds of higher content were 3 alcohols (linalool, α-terpineol, geraniol), 2 aldehydes (phenylacetaldehyde, crocinaldehyde), 2 ketones (β-ionone, phytoketone), 2 heterocyclic compounds (cis-linalool oxide, trans-linalool oxide), 1 esters (dihydroactinidiolide). The total relative content of volatile substances in sun-dried green tea in Gelanghe township was higher than that in Nannuoshan township and Xiding township, mainly in aldehydes. The dominant aroma components of sun-dried green tea in Bulangshan township were ketones and alkanes; The dominant aroma components in Xiding township were olefins, that was, sun-dried green tea from different producing areas had different dominant volatile substances.

In order to explore the composition of main volatile compounds and the difference of aroma compounds in Sauce-flavor Baijiu with different sweet flavor characteristics, sensory evaluation method was used to select Sauce-flavor Baijiu samples, the volatile components were analyzed by headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), and partial least squares discriminant analysis (PLS-DA) was used to analyze different Baijiu samples and their flavor differences substances. The results showed that the samples were divided into three groups, and the intensity values of sweet-flavor in each group were 4.0~5.0, 3.0~4.0 and 0.0~3.0, respectively, and a total of 68 volatile flavor compounds were characterized, including 27 esters, 12 alcohols, 10 aldehydes and ketones, 3 acids, 10 aromatics and 6 terpenes, among them, esters, aromatics and alcohols with sweet and fruity aromas were the three most abundant types of compounds in different Baijiu samples, and the content was the highest in Baijiu samples with a sweet flavor intensity greater than 3.0, indicating that these three types of substances had an important impact on the flavor characteristics of sweet aroma. There were 25 potential difference compounds affecting the three groups of Baijiu samples, and the related sweet flavor markers were mainly 3-methyl butanol, ethyl octanoate, isobutyl lactate and ethyl phenylacetate, indicating that these substances were the important aroma compounds that cause differences between different sauce-flavor Baijiu samples with different sweet flavor characteristics.

To clarify the key aroma compounds of Fuji apples and the influence of drying temperatures, the volatile compounds of Fuji apple slices dried by hot-air at 50, 60, 70 and 80 ℃ were characterized by head space solid-phase micro-extraction gas chromatography-mass spectrometer (HS-SPME-GC-MS) combined with electronic nose. The results showed that 64 volatile compounds were identified in fresh and four kinds of dried apple samples, including 23 esters, 18 alcohols, 8 aldehydes, 2 alkenes, 2 ketones, 3 lactones, 1 acid, 3 sulfur-containing compounds and 4 heterocyclic compounds. The differences between types and contents of volatile compounds in different samples were great. The content of aroma compounds in fresh samples was 397.059 mg/kg. Total volatile compounds contents in four hot-air dried samples from high to low were 64.189 mg/kg at 50 ℃, 57.703 mg/kg at 80 ℃, 32.124 mg/kg at 70 ℃ and 32.020 mg/kg at 60 ℃, respectively. Odor-active value (OAV) analysis showed that there were 8 key aroma compounds both in fresh apple sample and hot-air dried apple samples. They were α-farnesene (12746.11~1597.75), hexyl 2-methylbutyrate (755.62~6.90), hexanol (2988.00~168.54), 1-octene-3-ol (53.12~12.08), nonanal (1534.99~47.36), trans-2-nonenal (1202.98~189.38), linalool (1264.30~212.75) and 6-methy-5-hepten-2-one (11.27~3.90). The key aroma compounds identified in hot-air dried samples included 2-methyl-1-butanol (32.26~7.16), 3-methyl-4-heptanol (14.39~6.90), phenylethanol (11.11~4.67), octanal (211.25~84.36), 3-hydroxy-2-butanone (64.57~21.86), 3-methylthiopropanol (13.52~5.88) and 2-pentylfuran (26.44~14.88). Electronic nose analysis showed that there were differences in aroma profiles between fresh apple and apple slices dried by hot-air at different temperatures. The fresh samples and dried apple slices could be effectively distinguished by principle component analysis (PCA). Considering aroma and energy consumption, 80 ℃ hot air dehydration apple slices had better characteristic aroma than 50 ℃ hot air treatments. Therefore, 80 ℃ hot air drying was the optimal drying condition.

To explore the relationship between diet and human health, this study aimed to evaluate the beneficial effects of the existing Guangxi longevity dietary pattern on the human body from metabolomics. After 2 weeks of habitual diet, the selected volunteers followed this dietary pattern with high adherence for the same period. The blood and fecal samples were collected 3 times then performed metabolomics analysis, including before the habitual diet, the beginning (which was also the ending point of habitual diet) and the end of Guangxi longevity dietary pattern. The results showed that after the Guangxi longevity dietary intervention of volunteers, the relative abundance of serum histidine, glycerol, α-glucose and β-glucose was significantly increased (P

In order to determine the suitable cooking time of Morchella soup, the sensory indexes, volatile flavor substances and amino acids of Morchella soup boiled for 20, 40, 60 and 120 min were quantitatively analyzed. The results show that the color, smell and taste of Morchella soup were the best and the score was the highest when boiled for 40 min, and the score was significantly higher than that of other cooking time (P

The nutritional composition, physicochemical indexes and harmful substance contents of flaxseed oil during frying process under conventional frying condition were studied in this paper, and its frying performance was comprehensively analyzed by principal component analysis. The results showed that the unsaturation of flaxseed oil without frying was 81.77%. The content of α-linolenic acid was 47.50%, which was a kind of high nutritional value edible oil. During the 60 h (5 d)170 ℃ continuous frying, the color, acid value, peroxide value, refractive index, carbonyl value, polar components, tocopherol content and fatty acid composition of flaxseed oil changed significantly (P

In order to optimize the steam distillation extraction process of essential oil from Citrus reticulata Blanco cv. Manau Gan, fresh peel samples were used as materials, and ultrasonic assisted treatment was adopted. On the basis of optimized distillation equipment and single factor tests, Box-Behnken experiment was used to design for ultrasonic temperature, ultrasonic power and ultrasonic time. The essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the extraction effect of Clevenger distillation apparatus was better than the other three distillation devices. The optimal oil extraction process was obtained by response surface analysis: ultrasonic temperature 33 ℃, ultrasonic power 80 W, ultrasonic time 32 min. Under the optimal conditions, the extraction yield of essential oil reached 2.50%±0.02%. Twenty-nine compounds were identified by gas chromatography-mass spectrometry (GC-MS), accounted for 99.16% of the total volatiles, including alkenes (mainly D-limonene, content up to 88.35%), alcohols (mainly Linalool 0.18%), aldehydes (mainly Octanal 0.17%), et al. This research technique could be used for the extraction of essential oil from Citrus reticulata Blanco cv. Manau Gan.

Objective: By simulating the heating process of edible oil in daily life, the transformation and degradation conditions of tert butyl hydroquinone (TBHQ) in vegetable oil samples containing TBHQ were determined. The two transformation products of TBHQ, tert butyl p-benzoquinone (TQ) and 2,5-di-tert-butyl-1,4-benzoquinone (TBK), were finally determined by gas chromatography-mass spectrometry and matching of unknown compounds with the database. And a gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of tert-Butyl-hydroquinone (TBHQ) and its two degradation products 2-tert-Butyl-1,4-benzoquinone (TQ) and 2,5-di-tert-butyl-1,4-benzoquinone (TBK) in vegetableoil. Methods: The sample was dissolved in n-hexane saturated with acetonitrile and extracted with acetonitrile saturated with n-hexane. The acetonitrile layer was extracted twice, and the acetonitrile layer was combined. The acetonitrile layer was concentrated to nearly dry in 40 ℃ water bath and then redissolved with methanol, HP-5MS UI capillary column (30 m×0.25 mm, 0.25 μm) was used without splitter injection. Then selected the ion monitoring mode，gas chromatography-mass spectrometry determination, external standard method quantitative. Results: The linear range of the three compounds was good (R2>0.995). Under the three levels of concentration, the recoveries were 83.40%~107.71%, and the relative standard deviation (n=6) was less than 8.5%. The limits of quantitation (loqs) of TBHQ and TBK were 10 μg/kg and TQ was 50 μg/kg. 25 batches of samples were measured. TQ was measured in two batches of samples, and TBK was measured after heating treatment. Conclusion: The method is simple, sensitive, accurate and reliable. It is suitable for the simultaneous determination of TBHQ and its degradation products in vegetable oil.

Objective: The study aimed to compare the variance of constituents of volatile oil in the stems, leaves and flowers of Vitex negundo var. heterophylla (VNH). Methods: The volatile oil in the stems, leaves and flowers of VNH were extracted by hydrodistillation, respectively, and their constituents were analyzed and identified by GC-MS, and the differences in their chemical compositions were analyzed by principal component analysis (PCA) and cluster analysis. Results: Total of 83 volatile components were identified from different parts of the VNH, including olefins, alcohols, ketones, esters, etc. 14, 58 and 55 volatile components were detected from the stems, leaves, and flowers, accounting for 59.91%, 98.32% and 95.83% of the total volatile oils in each part, respectively. Only 8 volatile components were shared by three parts, whereas 4, 22 and 21 volatile components were unique to the stems, leaves and flowers, respectively. The differential components of the volatile oils from different parts of VNH were obtained by PCA, in which the signature volatile components in the stem were 2,4-bis (1,1-dimethylethyl)-phenol, 14-methyl-pentadecanoic acid, methyl ester, heneicosane, etc, and the trademark volatile components in the leaves were β-terpinene, elemol, caryophyllene oxide, etc, whereas the hallmark volatile components in the flowers were formed by sabenene, 2,3-dihydro-3-[2-aminoethyl]-5-methoxy-1,3- dimethyl-indole-2-one, citenamide, etc. As revealed by the results of the cluster analysis, the stems of VNH were clustered with the flowers and then with the leaves. Conclusion: The composition of the volatile oil in the stems, leaves and flowers of of VNH had certain variability, which would provide a scientific basis for the further medicinal or industrial exploitation of different parts of VNH.

The crude milk thistle oil was refined and degummed using membrane separation technology and the process was optimized. Taking flux and degumming as the main indicators, and referring to indicators such as iodine value, peroxide value, acid value, etc., inorganic alumina ceramic membranes with pore sizes of 300, 800 nm and 1 μm and organic membranes with a molecular weight cut-off of 10 kDa were screened. Three organic membranes including polyamide (PAN) membrane, cellulose acetate (CA) membrane and polyethersulfone (PES) membrane were screened, and membrane materials with low membrane pollution, high degumming rate and moderate flux were screened out. The selected PES membrane was optimized by orthogonal process in terms of membrane molecular weight cut-off, pressure and oil-soluble ratio. The composition of fatty acids before and after refining was compared with a gas-mass spectrometer, and the morphology of the membrane before and after the experiment was observed by scanning electron microscope (SEM). The results showed that the degumming rate of PES membrane was 73.33%, the flux was 14.69 L·m−2·h−1, the iodine value was 111.1 g/100 g, the peroxide value was 0.115 g/100 g, and the acid value was 5.7 g/mg. The overall effect was the best. The conditions of the membrane after orthogonal optimization were the membrane molecular weight cut-off of 8 kDa, the oil-soluble ratio of 1:3, and the pressure of 0.3 MPa. RSD was 1.93%

In order to study the effects of different cooking methods (frying, steaming and boiling) on the volatile flavor compounds in beef, solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to analyze the volatile flavor compounds of beef. GC-MS method was used to isolate and identify volatile flavor compounds in beef samples treated with different cooking methods. The results showed that 114 volatile flavor compounds were isolated and identified from beef samples treated by different cooking methods. The ways of cooking had significant effects on the volatile flavor compounds of beef, among which frying had the strongest effect, followed by steaming, and boiling had the slightest effect. A total of 61 compounds were detected in raw beef, while 59, 33 and 60 compounds were detected in steamed beef, fried beef and boiled beef, respectively. There were 14 volatile flavor compounds in common in raw beef, steamed beef, fried beef and boiled beef, which were listed in the following: 2-hydroxy-pentanoic acid methyl ester, hexanoic acid, dimethyl-silanediol, 1-octene-3-ol, 1-pentanol, nonanal, decanal, hexanal, tetradecanal, octanal, acetone, 2,3-octanedione, 3,7,11,15-tetramethylhexadiene-2-ene, methoxy-phenyl-oxime. The main volatile flavor compounds in raw beef were hexanoic acid ethyl ester and hexanoic acid (the relative contents were 16.15% and 11.17%, respectively). The main volatile flavor compounds in boiled beef were nonanal and 2, 3-octanedione (13.44% and 11.94%, respectively). The main volatile flavor compounds in steamed beef was hexanal (relative content was 44.89%). The main volatile flavor compounds in fried beef were formaldehyde, nonanal and hexanal (19.49%, 17.66% and 9.58%, respectively). The results of principal component analysis (PCA) showed that esters, hydrocarbons, acids and aldehydes might be the main factors affecting the differentiation of volatile flavor compounds in different samples. The results from this study would provide a technical reference for beef processing.

The essential oil from Calendula officinalis L. was extracted by microwave-assisted steam distillation. Taking the yield as the evaluation index, the extraction process of essential oil was optimized by orthogonal experiment on the basis of single factor test. The chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The antioxidant effect of the essential oil was evaluated by the scavenging activity of DPPH free radical, hydroxyl radical and ABTS+ free radical. The results showed that the optimum conditions for extracting the essential oil by microwave-assisted steam distillation were as follows: NaCl content 3%, ratio of material to liquid 1:30 g/mL, microwave power 240 W. Under these conditions, the yield of the essential oil was 0.156%. By GC-MS analysis, a total of 25 components were identified in the essential oil, accounting for 97.94% of the total components, mainly alcohols and terpenes. In the antioxidant test, the scavenging ability of the essential oil to DPPH free radical was weak. It had strong scavenging ability to hydroxyl radical and ABTS+ radical. In general, it had obvious antioxidant activity and a good dose-effect relationship. This study would provide more reliable technological parameters for large-scale production of Calendula officinalis L. essential oil, and provide basic data and reference for the evaluation of its antioxidant activity.

In order to study the removal effect of pesticide residues in fresh-cut potatoes by electrolyzed functional water combined with ultrasonic cleaning, the simulating pollution of procymidone, phorate, chlorothalonil and chlorpyrifos in fresh-cut potatoes with different cutting methods was carried out. After the detection of these samples by gas chromatography-mass spectrometry (GC-MS), the removal rates of four pesticide residues in fresh-cut potatoes treated with acid electrolyzed functional water (AcEW)-ultrasonic cleaning were obtained. The effects of washing solution, the ratio of sample to washing solution, ultrasonic power and washing time on pesticide removal rates were investigated. The results showed that the suitable washing solution for fresh-cut potato was AcEW; there was no significant difference (P>0.05) on pesticide removal rates under the conditions of different ratios of sample to washing solution. The optimal ultrasonic power of potato strip, chips, slices and diced potato were 200, 400, 400 and 400 W, respectively. Under these conditions, the mean removal rate of chlorpyrifos and phorate were 78.79%, 75.05%, 70.56% and 68.46%, respectively; and the mean removal rate of procymidone and chlorothalonil were 45.96%, 45.91%, 37.5% and 36.92%, respectively. And the optimal washing time of them were 10, 10, 20 and 20 minutes, respectively. Under these conditions, the mean removal rate of chlorpyrifos and phorate were 78.03%, 75.52%, 71.85% and 69.18%, respectively; and the mean removal rate of procymidone and chlorothalonil were 47.27%, 45.05%, 40.65% and 41.33%, respectively. The results obtained in this study provide theoretical and technical support for improving the pesticide residue control levels in cleaning process of fresh-cut potato.

In order to ameliorate the fishy aftertaste and value addition of Pangasius bocourti fillets, this article used Perilla frutescens water extract for deodorization. The fishy aftertaste and color difference were used as indicators, combined with electronic nose auxiliary analysis to conduct single-factor experiments. Afterwards, the deodorization process parameters were optimized by orthogonal experiments. GC-MS was used to distinguish the differences in volatile compounds before and after deodorization of Pangasius bocourti fillets. After analyzing the experimental results, it was found that with the help of the electronic nose, the best process conditions for deodorization of Pangasius bocourti fillets were: The concentration of Perilla frutescens aqueous extract was 3%, the deodorization time was 60 min, and the deodorization temperature was 20 ℃. Under this condition, the fish fillets had no obvious fishy aftertaste, and the flesh was white and had a light Perilla frutescens fragrance. After soaking in Perilla frutescens water extract, the main fishy aftertaste substances such as hexanal, nonanal and 1-octen-3-ol in the fish meat were greatly reduced. It could be seen that the Perilla frutescens water extract could effectively reduce the fishy aftertaste of Pangasius bocourti and ameliorate the flavor characteristics of fish fillets. This article would deliver a theoretical foundation for subsequent development and industrial production of Pangasius bocourti in the future.

Mature corn grains is an important food ration for residents in our country, but its edible flavor quality was rarely reported. The volatile organic components (VOCs) in whole grain powder with different treatment of 5 high-quality yellow grain maize varieties were detected with gas chromatography-mass spectrometry (GC-MS), the results showed that a total of 101 species of VOCs were identified, but only 60~70 species were found in a single variety. These VOCs could be divided into 12 categories, of which, the number of esters, alkanes and ketones were more, followed by alcohols, aldehydes and amides. When the composition of VOCs were analyzed, it was also found that there were about 20 species of components with high content at the level of over 106 peak area, which constituted 80% of the total volatile substances content, in these high content components, 13 were co-owned which were present in all samples, and 4~16 were specific which varied among varieties. There were two species of high content components at the level of 107 peak area，n-dodecane and tert-butanol were identified, which were considered to be important volatile substances in corn. The detection results also showed that the relative total content of VOCs in the samples distributed from 36.660 to 68.001 mg/kg. When they were compared each other, it was also found that the total content of VOCs was significantly different among varieties and samples, including different storage time and packages. The content of aroma substances in newly harvested grains was the highest. The ears or grains was stored naturally 1 year, its VOCs lost about 1/5. While the whole powder was stored naturally 1 year, its VOCs lost nearly a third. But the powder being stored in vacuum bags and under the low temperature 3 years, the loss of VOCs was slightly. These results suggested that the aroma substances content in corn was a variety characteristic. Excellent varieties and special production areas could effectively increase the kinds and the content of aroma substances in grains. Storage time and storage conditions could significantly affect the quality of aroma. Storage under the conditions of low temperature and vacuum could effectively maintain the quality of aroma. These results provided important reference data for quality evaluation of high quality edible corn.

Based on the metabolomic technique of GC-MS, the metabolites and metabolic differential mechanism of rice from Ning'an and Wuchang city were studied. SIMCA and R software were used for multivariate statistical analysis of the data. The results showed that the place of production had an influence on the quantity, content, type and proportion of the metabolites of Daohuaxiang rice. A total of 127 metabolites were identified in rice samples from the two regions. A total of 22 different metabolites were screened out through the analysis of the differences between the samples from the two regions. And it was found that the origin had the most significant influence on the contents of fatty acids and their derivatives. The results of metabolic pathway analysis showed that the main mechanism of rice metabolism difference in different producing areas was the metabolism of fatty acids. Linoleic acid, palmitic acid and fumaric acid were the three key metabolites. And the difference of metabolites type and content was related to rice quality. The research analyzes the different mechanisms of rice metabolism in different producing areas from the aspect of metabolite composition, which can provide theoretical support for the regional differentiation of rice production and the traceability of agricultural products.

To explore the mechanism of citrus pulp in absorption of flavor compounds, the composition, nitrogen adsorption-desorption isotherm of sweet orange pulp powder was tested, its microstructure was observed by scanning electron microscope (SEM), its adsorption capacity for flavor components in orange oil was tested and analyzed by gas chromatography-mass spectrometry (GC-MS). The results of component analysis showed that the sweet orange pulp powder was mainly composed of dietary fiber (51.87%±3.12%), protein (20.47%±0.58%), lipid (11.33%±1.60%), and starch (4.06%±0.59%). SEM observations and analysis of the nitrogen adsorption-desorption isotherm indicated that there were lots of wedges, slits and other irregular structures in the sweet orange pulp powder. The specific surface area of the sweet pulp powder was 2.98 m2/g. The results of GC-MS analysis showed that the sweet orange pulp powder had an obvious effect on the adsorption of typical aroma components of orange oil such as limonene, γ-terpinene, β-myrcene, β-phellandrene, linalool, octanal, nonanal, etc., especially of linear fatty aldehydes and oxygenated terpenoid, while had a relatively weak effect for bicyclic monoterpenoids such as α-pinene, sabinene. In summary, the wedges, slits formed by the cross-linking of the components in the sweet orange pulp powder were the key foundation for its absorption of flavor compounds. The results could provide a reference for the further development and utilization of sweet orange pulp.