Comparative evaluation of commercial Douchi by different molds:biogenic amines,non-volatile and volatile compounds

To provide new insights into the development and utilization of Douchi artificial starters,three common strains(Aspergillus oryzae,Mucor racemosus,and Rhizopus oligosporus)were used to study their influence on the fermentation of Douchi.The results showed that the biogenic amine contents of the three types of Douchi were all within the safe range and far lower than those of traditional fermented Douchi.Aspergillus-type Douchi produced more free amino acids than the other two types of Douchi,and its umami taste was more prominent in sensory evaluation(P<0.01),while Mucor-type and Rhizopus-type Douchi produced more esters and pyrazines,making the aroma,sauce,and Douchi flavor more abundant.According to the Pearson and PLS analyses results,sweetness was significantly negatively correlated with phenylalanine,cysteine,and acetic acid(P<0.05),bitterness was significantly negatively correlated with malic acid(P<0.05),the sour taste was significantly positively correlated with citric acid and most free amino acids(P<0.05),while astringency was significantly negatively correlated with glucose(P<0.001).Thirteen volatile compounds such as furfuryl alcohol,phenethyl alcohol,and benzaldehyde caused the flavor difference of three types of Douchi.This study provides theoretical basis for the selection of starting strains for commercial Douchi production.

Effect of different drying methods on the amino acids,α-dicarbonyls and volatile compounds of rape bee pollen

The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.

Exploring Nutritional Compositions,Volatile Compounds,Health Benefits,Emerging Processing Technologies,and Potential Food Products of Glutinous Rice:A Review

Glutinous rice(Oryza sativa var.glutinosa)stands out as one of the most popular rice varieties globally,amidst thousands of rice cultivars.Its increasing popularity is attributed to its rich nutritional compositions and health benefits.This review aims to summarize the nutritional compositions,volatile compounds,and health benefits of glutinous rice.Further,in-depth studies are necessary to explore the utilization of glutinous rice in enhancing processing technologies and developing new food products.Glutinous rice has been shown to possess numerous health benefits,including antioxidant activity,bioactive compounds,anti-cancer properties,anti-inflammatory effects,anti-diabetic potential,and cholesterol-lowering effects.Besides its nutritional compositions,the major volatile compounds identified in glutinous rice could serve as a functional food for human consumption.Emerging processing technologies related to glutinous rice are elaborated to improve the latest developments for incorporating them into various food products.

Understanding changes in volatile compounds and fatty acids of Jincheng orange peel oil at different growth stages using GC-MS

Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.

Comprehensive lipidomics and volatile compounds profiling reveals correlation of lipids and flavors in DHA-enriched egg yolk

DHA-enriched eggs have gained popularity due to their unique nutritional value,but their flavor can be challenging for some consumers to accept.The study analyzed the correlation of lipids and flavors in DHA-enriched egg yolks using comprehensive lipidomics and volatile compound analysis.The results showed that 411 lipids were detected in two egg yolk samples.Among them,148 lipid species,including 48 DHA-containing lipids,were significantly higher in DHA-enriched egg yolks than in Common ones(P<0.05).Furthermore,of the 24 volatile compounds detected,the contents of benzaldehyde,heptanal,hexanal,decanal and 2-nonanone in DHA-enriched egg yolks were significantly higher than in Common egg yolks(P<0.05).The“fishy”smell characteristic of DHAenriched egg yolks was mainly caused by volatile aldehydes,which may be produced through the hydrolysis of lipids in the egg yolk to free fatty acids and further oxidation.Analysis of the correlation network diagram revealed that phospholipids containing docosahexaenoic acid(DHA),linoleic acid,or oleic acid chains were the main contributors to the characteristic flavor of DHA-enriched egg yolks.Overall,this study explored the effect of different lipids on the flavor of DHA-enriched egg yolks and provided a theoretical basis for the production and improvement of DHA-enriched eggs.

Effect of Metaxenia on Volatile Compounds in Bagged Apple Fruit of Fuji

In the present study, the effect of pollen grain sources on volatile com- pounds in bagged apple fruit of Yan Fuji 3, grown at two experiment sites and pol- linated by pollens of other five cultivars was evaluated, to select appropriate poll- enizer cultivars for Fuji, and to provide a theoretical basis for improving the flavor and aroma of bagged apple fruit of Fuji. The results proved the significant metaxe- nia effect of the five pollenizer cultivars on volatile compounds of bagged apple fruit of Fuji. The numbers of both volatile compounds and characteristic aroma com- pounds in bagged apple fruit pollinated by Golden Delicious were larger and those of the fruit pollinated by Gala were smaller at both experiment sites. However, there were differences in the numbers of volatile compounds and characteristic aroma compounds among the fruits pollinated by Starkrimson, Jinxiuhaitang and Ruby at both experimental sites. The differences were caused by 12 compounds that only existed at a low level in certain samples. All of them were not the aroma contribu- tors except ethyl 2-methylbutyrate. The content of alcohols in bagged Fuji fruit was largely increased by Starkrimson and Ruby pollination; the content of aldehydes was obviously increased by Golden Delicious, Starkrimson and Gala pollination; the con- tents of esters and terpenes were significantly increased by Golden Delicious, Starkrimson and Ruby pollination. Jinxiuhaitang pollination showed no significant ef- fects for improving the content of four categories of volatile compounds. The metax- enia of the pollenizer cultivars on volatile compounds in bagged Fuji fruit was stable at the two experimental sites.

Effect of the Inclusion of Chestnut in the Finishing Diet on Volatile Compounds of Dry-Cured Ham from Celta Pig Breed

The effect of the inclusion of chestnut in pigs ifnishing diet on volatile compounds of dry-cured Celta ham was studied. Twelve hams of each type （from three different pigs ifnishing diets：concentrate （CO）, mixed （MI） and chestnut （CH）） were used. Volatiles were extracted using a purge-and-trap method and analyzed by gas chromatography/mass spectrometry （GC/MS）. Thirty-nine volatile compounds were identified in dry-cured Celta ham samples. Most abundant volatiles in ham samples were aldehydes, which represented respectively, 53% （CO）, 51% （MI） and 46% （CH） of the total volatile composition. With the exception of 2-butenal, 2-methyl, all aldehydes were affected by feeding system. On the other hand, hydrocarbons n-alkanes were the second major group in the volatile proifle of dry-cured Celta hams and represented 28.9, 35.7 and 32.4%of the total volatile composition for CO, MI and CH groups, respectively. Ham samples from chestnut group showed a higher content of alcohols and this result could be related with the inclusion of chestnut in the ifnishing diet of pigs. Principal component analysis showed a good separation among groups. The discriminant analysis selected eight variables （butanoic acid, hexanal, octanal, nonenal （E）, decenal （E）, tetradecane, decane trimethyl and pyridine 2-methyl） and calculated two discriminating functions to predict if chestnut has been included in the ifnishing diet. Thus, it was possible to discriminate between groups fed with ifnishing diets containing chestnuts in their composition （mixed and chestnut group）.

Co-Treatment of EFF and 1-MCP for Enhancing the Shelf-Life and Aroma Volatile Compounds of Oriental Sweet Melons(Cucumis melo var.makuwa Makino)

Compared to other melon types, oriental sweet melon （Cucumis melo var. makuwa Makino） is quite a different species with a shorter shelf-life due to its typical climacteric behavior and thin pericarp. The purpose of this experiment is to explore the effects of co- treatment of enhanced freshness formulation （EFF） and 1-methylcyclopropene （1-MCP） on physiological changes and the content of aroma volatile compounds introduced by them of two oriental sweet melon cultivars （Yumeiren and Tianbao） during storage. The melons were stored in incubators with temperature of 15~C and a relative humidity of 85% for 24 d during which fruit quality and related physiological index were measured. Compared to the control, both treatments delayed fruit weight loss rate and kept the fruit firmness, water content and soluble solids content. Ascorbate peroxidase （APX） and phenylalanine ammonia lyase （PAL） activities showed fluctuations in treated melons, while lipoxygenase （LOX） activity （P〈0.01） and malondialdehyde （MDA） content （P〈0.05） decreased compared to control. During the early stage of storage, alcohols and aldehydes were the main volatile compounds, and esters gradually increased during storage. Of all the esters, acetic esters were the main components, followed by oxalic acid esters and other esters. The total content of aroma volatile compounds, esters, alcohols and aldehydes of co-treated melons were all higher than those of 1-MCP treated and control melons. In addition, the aroma volatile peak of co-treated melons occurred later than that of 1-MCP treated and control melons. In summary, co-treatment of EFF and 1-MCP was more beneficial than 1-MCP treatment to delay ripening and senescence, maintain fruit quality, enhance shelf-life and improve levels of aroma volatile compounds.

Changes in Volatile Compounds of Sweet Potato Tips During Fermentation

Volatile compounds in fresh and fermented sweet potato tips at O, 10, 20, 30, and 40 d during fermentation were investigated. A new parameter named ＂relative odor activity value （ROAV）＂ was applied in evaluating the contributions of volatile compounds to flavor, considering odor threshold. The results showed that volatile compounds could be clustered in the following chemical families： alkenes （most of them were sesquiterpene）, alcohols, aldehydes, ketones, and esters in decreasing order. During fermentation, the concentrations of alkenes and ketones were increased and then decreased continuously. Alcohols and esters were increased; while the concentrations of aldehydes decreased. Interestingly, fermenting processes （0-20 d） may contribute to the increase of alkenes and ketones. Major compounds that were identified in all samples include α- and B-caryophyllene, β- and γ-elemene, and β-cubebene （in decreasing order）. The changes of their concentrations during fermentation were the same as that of alkenes. Caryophyllene was abundant in all of the samples examined. It has anti-tumour, anti-inflammatory and anti-pests activities. It can mediate interactions among plant, herbivores and their natural enemies. β- and γ-elemene, which have been used as antitumor drugs, have not been reported previously as volatiles from sweet potato tips. β-cubebene with antioxidant activity can be used as natural preservatives in food and/or by the pharmaceutical industry.

Aroma Volatile Compound Analysis of SPME Headspace and Extract Samples from Crabapple (Malus sp.) Fruit Using GC-MS

Volatile compounds from the ripened crabapple fruit of six varieties （Red Splendor, Strawberry Parfait, Pink Spire, Radiant, Sparkler, and Flame） were analyzed by the use of the SPME/GC/MS method. The changes in the volatiles between the ripened and upon full maturity fruit states were studied in Red Splendor and Strawberry Parfait. An effort was made to summarize an effective method for searching and identifying new idioplasms containing a particular fruit aroma within Malus. A total of 37 compounds were identified from the sample. The main aroma volatiles of the six varieties of fruit were comprised of 2-hexenal, 3-hexenal, hexanal, 2,4-hexadienal, benzaldehyde, diethyl phtbalate. The main volatile compound of the crabapple fruit was 2-hexenal, but the relative content percentages were different （45.37, 21.98, 33.56, 32.21, 38.60, and 45.88%）. The aroma components accumulated differently as the fruits ripened. The relative content of aldehydes and esters decreased as alcohols increased after the Red Splendor and Strawberry Parfait fruit ripened. For Red Splendor, the main volatile was still 2-hexenal, but the relative content decreased to 42.89%, and the relative content of alcohols increased by 13.86% as aldehydes and esters declined by 12.16 and 7.18%, respectively. For Strawberry Parfait, the main volatile was changed to cyclohexanol, and the relative content increased to 46.43%, while the relative content of alcohols increased by 49.03% as aldehydes and esters declined by 23.74 and 9.34%, respectively.

Effects of thyme(Thymus vulgaris L.)addition on the volatile compounds of mutton broth during boiling

To investigate the effects of thyme(Thymus vulgaris L.)addition on the flavor modification of mutton broth during boiling,three mutton-broth samples with various thyme contents 0.06%(S1),0.30%(S2),and1.50%(S3)were analyzed and compared,without thyme as control(0.00%,S0).The meaty,fatty,pastoral flavor and spicy were chosen as sensory attributes to evaluate the flavor of the mutton-broth samples.Sensory results were significantly different(P<0.001),with S2 having the optimum overall acceptability.A total of 99 volatile compounds were identified by gas chromatography-mass spectrometry,among which19 compounds were considered as the odor-active compounds according to their odor activity values.Significant changes(P<0.05)appeared in most volatiles in S0 with thyme addition,especially aldehydes.Free fatty acids(FFAs)were also identified,and all of them significantly increased with increased thyme(P<0.05).Correlation analysis of odor-active compounds,FFAs,and sensory attributes through partial least squares regression indicated the important volatiles and FFAs remarkably contributed to the mutton broth samples,and further confirmed that the 0.30%of thyme may be a desirable addition amount for the sensory characteristics of mutton broth.

Comparison of volatile and semivolatile compounds from commercial cigarette by supercritical fluid extraction and simultaneous distillation extraction

Supercritical carbon dioxide fluid extraction (SFE) was studied as a rapid method for extraction of volatile and semivolatile compounds of Chinese commercial cigarettes. The method was compared with simultaneous distillation and extraction (SDE). Temperature and pressure for the SFE were optimized. The extracts obtained by the two methods showed different characters in composition and represented differently the flavor characteristics of tobacco; compared to SDE, SFE can extract compounds within a shorter time and avoid the thermal degradation and solvent contamination of samples. The extracts by the two extraction methods are complementary for investigating the flavor characteristic of tobacco products.

Analysis of Aroma Volatile Compounds in Fuji Apple Using SPME with Different Fiber Coatings

The aroma volatile compounds in Fuji apple were isolated by solid-phase microextraction( SPME),and detected by gas chromatography-mass spectrometry( GC-MS). The results showed that the optimal retention time of the heating up of capillary columns was 5 min. Of the seven fibers used in this work,DVB/CAR/PDMS was found to be the most suitable to extract the aroma volatile compounds in Fuji apple. A total number of 43 volatile compounds were identified according to their retention time on capillary columns and their mass spectra,including eleven esters,ten alcohols,ten aldehydes,seven alkenes,two anhydrides,one ketone,one phenol and one ether. This detection method will provide a new foundation for analysis of volatile compounds in apple were identified.

Volatile Compounds Selection via Quantile Correlation and Composite Quantile Correlation: A Whiting Case Study

The freshness and quality indices of whiting (Merlangius merlangus) influenced by a large number of chemical volatile compounds, are here analyzed in order to select the most relevant compounds as predictors for these indices. The selection process was performed by means of recent statistical variable selection methods, namely robust model-free feature screening, based on quantile correlation and composite quantile correlation. On the one hand, compounds 2-Methyl-1-butanol, 3-Methyl-1-butanol, Ethanol, Trimethylamine, 3-Methyl butanal, 2-Methyl-1-propanol, Ethylacetate, 1-Butanol and 2,3-Butanedione were identified as major predictors for the freshness index and on the other hand, compounds 3-Methyl-1-butanol, 2-Methyl-1- butanol, Ethanol, 3-Methyl butanal, 3-Hydroxy-2-butanone, 1-Butanol, 2,3-Butane- dione, 3-Pentanol, 3-Pentanone and 2-Methyl-1-propanol were identified as major predictors for the quality index.

Effects of Grafting on Volatile Compounds in Bitter Gourd Fruit

[Objectives]This study was conducted to explore the effects of grafting on volatile compounds in bitter gourd fruit.[Methods]The volatile compounds and relative contents of grafted and non-grafted fruit were analyzed by headspace solid phase micro-extraction with gas chromatography-mass spectrometry.[Results]There were 59 volatile compounds in Haiyan No.2S,including six unique compounds.There were 58 volatile compounds in Haiyan No.2J,including five unique compounds.[Conclusions]This study provides a scientific basis for further analysis of bitter gourd flavor regulation mediated by grafting.

Multivariate Optimization of Volatile Compounds Extraction in Chardonnay Wine by Headspace-Solid Phase Micro Extraction and Gas Chromatography Coupled with Tandem Mass Spectrometry

A method for optimization of extraction of volatile compounds in Chardonnay wine was developed using headspace-solid phase microextraction (HS-SPME) and gas chromatography coupled with triple quadrupole tandem mass spectrometry (GC-MS/MS). Optimization of the HS-SPME conditions, temperature (T, °C) and extra-ction time (t, minutes), was carried out using a 22 factorial central composite rota- tional design (CCRD). Total area of chromatographic peaks of nineteen compounds was monitored in order to identify the best response and the data was collected on multiple reaction monitoring (MRM) mode. The mathematical model that describes the response surface for the CCRD was validated using the analysis of variance (ANO VA) with 95% of confidence level. This model showed a lack of fit based on mean square pure error ratios for each response, in which Fcalculated was 2.23 higher than Ftabulated. Even though the models cannot be rigorously used to make quantitative predictions, the coefficients of the model, especially the linear ones, are useful for understanding systematic behaviour of the response values as a function of the factor levels. Multivariate statistical design can be used in optimization of HS-SPME extraction parameters with reduced number of experiments and can be useful in sampling method of volatile compounds of Chardonnay wines analysis by CG-MS/MS. The optimal condition achieved in this method was 30°C and 45 minutes of extraction.

Identification of Volatile Compounds in Codfish(Gadus) by a Combination of Two Extraction Methods Coupled with GC-MS Analysis

Codfish is a kind of abyssal fish species with a great value in food industry. However, the flavor of codfish, especially the unpleasant odor, has caused serious problems in its processing. To accurately identify the volatile compounds in codfish, a combination of solid phase micro-extraction(SPME) method and simultaneous distillation extraction(SDE) method was used to extract the volatiles. Gas chromatography-mass spectrometry(GC-MS) along with Kovats indices(KI) and authentic standard compounds were used to identify the volatiles. The results showed that a total of 86 volatile compounds were identified in codfish, of them 24 were extracted by SDE, 69 compounds by SPME, and 10 compounds by both SDE and SPME. Seventy volatile compounds were found to have specific odors, of them 7 typical compounds contributed significantly to the flavor of codfish. Alcohols(i.e.,(E)-2-penten-1-ol and 2-octanol), esters(i.e., ethyl butyrate and methyl geranate), aldehydes(i.e., 2-dodecenal and pentadecanal) contributed the most to fresh flavor while nitrogen compounds, sulphur compounds, furans, as well as some ketones(i.e., 2-hydroxy-3-pentanone) brought unpleasant odor, such as fishy and earthy odor. It was indicated that the combination of multiple extraction methods and GC-MS analysis can enhance the accuracy of identification, and provide a reference for the further study on flavor of aquatic products.

The Characterization of Steam Distillation as an Extraction Method to Extract Volatile Compounds from <i>Prunella vulgaris</i>and the Investigation of Their Anti-Tumorous Effect

Prunella vulgaris (PV) is a perennial plant which is widely grown around the world. It has been widely used as a medicinal treatment for generations. Previous studies showed extracts from this plant had a wide range of therapeutic efficacy, including anti-tumorous effect. However, the volatile organic compounds (VOCs) extracted from it were rarely explored. This paper reports on the characterization of a steam distillation process to extract VOCs in PV and also the anti-tumorous effects of the PV distillate using the tetrazolium-based Cell Counting Kit-8 (CCK-8) as the test agent, when the VOCs were used to treat oral squamous cancer cells, SSC154. It was found that most abundant VOCs came out steadily and continuously for as long as the duration of the steam extraction could extend. However, some compounds such as benzaldehyde did show depletion as the distillation process progressed, while some compounds such as caryophyllene oxide was only sparsely found at the beginning of distillation. The PV distillate was mildly effective in its cytotoxicity to cancer cells SCC154, in a dosage dependent manner.

Discrimination of pharmacodynamic components and volatile compounds of Poria cocos cultivated with five different materials based on GC-IMS analysis

Objectives:The chemical constituents of Poria cocos grown with different substrates vary significantly;thus,identifying and comparing their biomarkers are important.Materials and Methods:Herein,the chemical constituents of Poria cocos obtained with five different substrates were assessed using gas chromatography–ion mobility spectrometry(GC-IMS),high-performance liquid chromatography and multivariate statistical analysis.Results:The content of moisture,ash,alcohol-soluble matter,and heavy metals,except for those of the miscellaneous wood Poria cocos,conform to the specifications defined in the Chinese Pharmacopoeia(Edition 2020),and the polysaccharide contents are all greater than 57%.Conclusions:Based on GC-IMS and the established fingerprints,87 compounds were detected,70 of which were identified in each group.Multivariate statistical analysis revealed seven compounds(two esters,three alcohols,and two aldehydes),which could be considered as potential marker compounds for discrimination.

Modern approaches for detection of volatile organic compounds in metabolic studies focusing on pathogenic bacteria:Current state of the art

Pathogenic microorganisms produce numerous metabolites,including volatile organic compounds(VOCs).Monitoring these metabolites in biological matrices(e.g.,urine,blood,or breath)can reveal the presence of specific microorganisms,enabling the early diagnosis of infections and the timely implementation of tar-geted therapy.However,complex matrices only contain trace levels of VOCs,and their constituent com-ponents can hinder determination of these compounds.Therefore,modern analytical techniques enabling the non-invasive identification and precise quantification of microbial VOCs are needed.In this paper,we discuss bacterial VOC analysis under in vitro conditions,in animal models and disease diagnosis in humans,including techniques for offline and online analysis in clinical settings.We also consider the advantages and limitations of novel microextraction techniques used to prepare biological samples for VOC analysis,in addition to reviewing current clinical studies on bacterial volatilomes that address inter-species in-teractions,the kinetics of VOC metabolism,and species-and drug-resistance specificity.