P omegranate(Punica granatum L.)has attracted considerable attention in world markets due to its valuable nutrients and highly appreciated sensory properties.The aroma profiles of 4 varieties of pomegranate juice,incl...P omegranate(Punica granatum L.)has attracted considerable attention in world markets due to its valuable nutrients and highly appreciated sensory properties.The aroma profiles of 4 varieties of pomegranate juice,including Dahongtian(DP),Jingpitian(JP),Luyudan(LP),and Tianhonngdan(TP),were investigated via gas chromatography-mass spectrometry(GC-MS)and gas chromatography-olfactometry(GC-O)analyses.A total of 43 volatile compounds were identified by using GC-MS.Among these compounds,16 were considered as potential aroma-active compounds as detected by GC-O.These compounds belonged to the classes of terpinenes,alcohols,and aldehydes.Eleven volatile compounds were defined as the main contributors to the overall aroma of pomegranate juice due to their high odor activity values(OAVs≥1).Aroma recombination and omission tests confirmed thatβ-myrcene,1-hexanol,and(Z)-3-hexen-1-ol were the key aroma compounds,and limonene,1-octen-3-ol,linalool,and hexanal were important aroma-active compounds in DP samples.展开更多
In the present work,the fruits of four Morus species,namely Morus alba (white mulberry),Morus nigra (black mulberry),Morus laevigata (large white fruit),and Morus laevigata (large black fruit),were analyzed for proxim...In the present work,the fruits of four Morus species,namely Morus alba (white mulberry),Morus nigra (black mulberry),Morus laevigata (large white fruit),and Morus laevigata (large black fruit),were analyzed for proximate composition,essential minerals,and antioxidant potentials.For this purpose,the ripe fruits were collected from the northern regions of Pakistan.The major nutritional components moisture,ash,lipids,proteins,fibres,carbohydrates,and total sugar) were found to be in the suitable range along with good computed energy.Total dry weight,pH,and titratable acidity (percent citric acid) were (17.60±1.94)–(21.97±2.34) mg/100 g,(3.20±0.07)–(4.78±0.15),and (0.84±0.40)%–(2.00±0.08)%,respectively.Low riboflavin (vitamin B2) and niacin (vitamin B3) contents were recorded in all the fruits,while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW).The mulberry fruits were rich with regard to the total phenol and alkaloid contents,having values of (880±7.20)–(1650±12.25) mg/100 g FW and (390±3.22)–(660±5.25) mg/100 g FW,respectively.Sufficient quantities of essential macro-(K,Ca,Mg,and Na) and micro-(Fe,Zn,and Ni) elements were found in all the fruits.K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g,while Ca,Na,and Mg contents were (440±3.21)–(576±7.37),(260±3.86)–(280±3.50),and (240±3.51)–(360±4.20) mg/100 g,respectivly.The decreasing order of micro-minerals was Fe>Zn>Ni.The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits.Based on the results obtained,mulberry fruits were found to serve as a potential source of food diet and natural antioxidants.展开更多
Cost problem is always a bottleneck which ties to the development and the competition ability in the enterprise of our country, especially in state-owned enterprise. Practice proves that traditional cost control can n...Cost problem is always a bottleneck which ties to the development and the competition ability in the enterprise of our country, especially in state-owned enterprise. Practice proves that traditional cost control can not satisfy the needs of enterprises. Enterprises are seeking better cost control approach with great efforts in order to calculate and control cost more accurately, and require cost control system has more strong functions. This paper analyzes value chain based cost control approach, and applies the gray relevancy analysis to the approach rightly.展开更多
A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and i...A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.展开更多
Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic bloc...Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.展开更多
μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postm...μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied. The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M. longissimus during earlier aging periods compared with conventional chilling. But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain. The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities.展开更多
The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break...The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break-in(3.5%-7.5%of total polar compounds(TPC)),optimum(7.5%-22.18%of TPC),and degrading stages(above 22.18%of TPC).Further,in order to distinguish the key aroma compounds in each stage,the FFs prepared in RO at TPC of 3.5%(FF4),14.5%(FF15),and 26.96%(FF27)and their relevant oils(RO4,RO15,RO27)were selected for sensory-directed analysis.The results revealed that the FF4 had low contents of(E,E)-2,4-decadienal(deep-fried odor)which also caused lower sensory score in FF4 sample.The higher contents of(E,E)-2,4-decadienal in FF15 induced its higher deep-fried odor.The FF27 had higher hexanoic acid(sweaty odor),heptanoic acid,nonanoic acid,benzene acetaldehyde(stale odor),and trans-4,5-epoxy-(E)-2-decenal(metallic odor)compared with FF4 and FF15,thus leading to the undesirable flavor of FF27.Moreover,the decrease of 2,5-dimethylpyrazine and 2-ethyl-6-methyl-pyrazine in FF27 induced the lower roasty flavor,which may also lead to the decline of the sensory score.Similarly,the higher contents of(E)-2-undecenal,hexanoic acid,heptanoic acid,and nonanoic acid in RO27 lead to increase its rancid score and thus lower the sensory score.展开更多
A series of long-chain quaternary ammonium hydroxides were synthesized from tertiary amines and confirmed by ~1H NMR and FTIR.Surface properties and pH of these surfactants were investigated.The critical micelle conce...A series of long-chain quaternary ammonium hydroxides were synthesized from tertiary amines and confirmed by ~1H NMR and FTIR.Surface properties and pH of these surfactants were investigated.The critical micelle concentrations（CMC） of the synthesized quaternary ammonium hydroxides are lower than the conventional quaternary ammonium surfactants.The micelles shapes of these long-chain quaternary ammonium hydroxides in aqueous solution are spherical at a concentration of 0.1 mol/L.The pH values of the synthesized quaternary ammonium hydroxides are 12.25-12.51.展开更多
Radish is a root vegetable with significant nutritional and economic value.However,there is limited information on the flavor and taste profiles of different radish varieties.In this study,headspace gas chromatography...Radish is a root vegetable with significant nutritional and economic value.However,there is limited information on the flavor and taste profiles of different radish varieties.In this study,headspace gas chromatography-ion mobility spectrometry was used to investigate the characteristic volatile compounds in Weixian green radish,establishing its volatile compound fingerprint.Further,its volatile compound composition was compared with those of other radish varieties.A total of 46 compounds were identified in the Weixian green radish,including 19 aldehydes,six alcohols,five esters,six ketones,three furans,three pyrazines,and four other compounds.Among different radish varieties,the Weixian radish contained the largest number of volatile compounds,followed by hybrid and green-root radish samples.Flavor differences among the different radish varieties were mainly affected by the type and content of esters,aldehydes,and ketones,among which 1-nonanal,propanal,1-penten-3-one,and isobutyric acid methyl ester were the key flavor contributors.This study not only reveals the differences in the flavor compounds between different radish varieties but also provides a scientific basis for the geographical protection of varieties and market positioning of radishes in Weixian County.展开更多
To explore a novel producing strategy for enhancing antioxidant activity and aroma of low-ethanol kiwi wine,kiwifruit juice was sequential fermentation with indigenous Zygosaccharomyces rouxii(Zr)and Saccharomyces cer...To explore a novel producing strategy for enhancing antioxidant activity and aroma of low-ethanol kiwi wine,kiwifruit juice was sequential fermentation with indigenous Zygosaccharomyces rouxii(Zr)and Saccharomyces cerevisiae(Sc)without adding sugars.The organic acids,bioactive compounds,volatile constituents,antioxidant capacities and sensory profiles were measured to evaluate the performance of different inoculation ratios.The results indicated that compared with pure fermentation of Sc,the sequential fermentations significantly increased the total flavonoids,total phenols,some mono-phenols and antioxidant activities of the low-ethanol kiwi wines,and resulted in a positive effect on organic acids mainly by reducing the content of malic acid.At the same time,sequential fermentations significantly enhanced the aroma profile of the low-ethanol kiwi wines.The higher inoculation ratio of Zr greatly increased the complexity of the volatiles,improving sweet odor of the wines.While the similar inoculation ratio of Zr and Sc significantly increased the volatile contents,intensifying the tropical fruity and kernel fruity.In addition,the partial least-squares regression analysis showed that aldehydes resulted in sourness,ethyl esters and acetate esters possessed a positive impact on tropical fruity and kernel fruity.展开更多
Citri Sarcodactylis Fructus(CSF)has pharmacological effects such as anti-inflammatory and antihypertensive,and is widely used as medicine and tea.Due to the different physical and chemical properties of CSF from each ...Citri Sarcodactylis Fructus(CSF)has pharmacological effects such as anti-inflammatory and antihypertensive,and is widely used as medicine and tea.Due to the different physical and chemical properties of CSF from each growing area,we quickly distinguish CSF from different regions by determining the characteristic flavor.This study aimed to investigate the variations in volatile flavors of different CSF originating from Jinhua(JFC),Guangdong(GFC),and Yunnan(YFC).Sensory evaluation,combined with gas chromatography-ion mobility spectrometry(GC-IMS)and gas chromatography-mass spectrometry(GC-MS),was employed to analyze the volatiles of CSF.GC-IMS showed each sample exhibited its characteristic peak,with YFC demonstrating higher peak areas compared to the others.GC-MS showed that terpenes constituted the highest proportion of volatiles in CSF samples,with limonene andγ-terpinene being the major components in finger citron.Odor activity value(OAV)in combination with principal component analysis(PCA)demonstrated that specific compounds such as dimethyl anthranilate,1,3,8-p-menthatriene,2-undecanone,and geranyl propionate contributed significantly to the flavor profile of JFC.Similarly,α-Pinene,β-phellandrene,anethole,and meta-cymene played key roles in the flavor profile of GFC,whereas(Z)-β-ocimene,1,8-cineole,citronellol,6-methyl-5-hepten-2-one,β-ionone,and p-cymene were identified as characteristic flavor compounds of YFC.Sensory evaluation showed significant flavor distinctions among the three types of CSF,with JFC exhibiting a prominent fruit aroma,GFC showing an evident herbal flavor,and YFC possessing a distinct floral aroma in its overall profile.These findings provided information on the differentiation of CSF originating from various geographical regions at a molecular level.展开更多
Mulberry leaf tea(MLT),a traditional medicinal tea in Asia,is beloved by Chinese consumers for its unique sweet and mellow taste and its well-documented beneficial effects in combating metabolic diseases.Therefore,a c...Mulberry leaf tea(MLT),a traditional medicinal tea in Asia,is beloved by Chinese consumers for its unique sweet and mellow taste and its well-documented beneficial effects in combating metabolic diseases.Therefore,a comprehensive study on the aroma,flavor,and anti-NAFLD(nonalcoholic fatty liver disease)effects of MLT under different fermentation times using chromatography,statistics,and network pharmacology was conducted.A total of 110 volatile compounds and 25 non-volatile compounds were identified from three types of MLT samples and mulberry leaves.With the extension of fermentation time,the bitterness of MLT decreased significantly,and the aroma gradually changed from fresh to intense.Major aroma-contributing substances and 8 characteristic differential substances were screened using ROAV values and statistical analysis.The molecular docking predicted that the detected flavonoid glycosides have a high binding energy with bitter receptors and PRP,ranging from-4.4 to-7.9 kcal/mol.By combining this with practical analysis,it was concluded that the flavonoid glycosides may enhance the bitterness and astringency in mulberry leaves.The network pharmacology approach was used to conduct target network,GO pathway,and KEGG enrichment analysis on 13 potential substances with medicinal value,it is found that MLT mainly exerts its anti-NAFLD effect by regulating metabolism and cancer pathways.展开更多
The key aroma compounds of five yeast extracts(YE)were identified comprehensively by solvent-assisted flavor evaporation(SAFE),simultaneous distillation extraction(SDE)and solid-phase microextraction(HS-SPME)combined ...The key aroma compounds of five yeast extracts(YE)were identified comprehensively by solvent-assisted flavor evaporation(SAFE),simultaneous distillation extraction(SDE)and solid-phase microextraction(HS-SPME)combined with sensomics approach and convolutional neural network(CNN)framework.The results found 349 volatiles via three methods,with 51 in common,highlighting their combined importance.Forty-nine aroma compounds(FD factor>27)were identified by aroma extract dilution analysis,of which 40 had OAV≥1.Five YEs contained 34,26,16,27,and 27 key aroma compounds respectively,sharing only seven:δ-dodecalactone,2,5-dimethylpyrazine,2-ethyl-6-methylpyrazine,dimethyl trisulfide,indole,benzaldehyde,and 2-methoxyphenol.Additionally,unique key aroma-active compounds for Y2 wereγ-undecalactone,2,3-diethylpyrazine and 2-naphthalenol,and for Y1,Y4 and Y5 were 2-formylpyrrole,4-methyl-pentanoic acid andα-angelica lactone.Roasted and meaty aromas originated from pyrazines,lactones and phenols were prominent sensory attributes of YE.The CNN model showed great fitting and prediction capabilities(91%training set accuracy,82%validation set accuracy at the 50th epoch),reflecting aroma characteristics of YE,with high similarity to results of OAV analysis results.This research combined different extraction methods with sensomics approach and CNN,providing profound insights into YE aroma compounds and thus helping to production of YEs with desirable aroma profiles.展开更多
In this study,electronic sensors,gas chromatography-mass spectrometry(GC-MS),and GC-olfactometry(GC-O)were used to analyze the flavor of pomegranate seed oil(PSO)extracted from roasted pomegranate seeds.A preliminary ...In this study,electronic sensors,gas chromatography-mass spectrometry(GC-MS),and GC-olfactometry(GC-O)were used to analyze the flavor of pomegranate seed oil(PSO)extracted from roasted pomegranate seeds.A preliminary study was conducted to determine the extent to which roasting treatment positively affects the physicochemical and sensory properties of pomegranate seeds,and a total of four conditions including raw were selected(raw,160℃for 15 min,160℃for 20 min,180℃for 10 min).This study aimed to determine if the beneficial effects of roasting seeds are retained when the oil is extracted from the seeds,and to explore their potential use in the food industry as a fat-soluble material.Electronic tongue(E-tongue)analysis revealed that roasting enhanced umami and sweetness while reducing bitterness.A total of 46 and 50 volatile compounds were detected using the electronic nose(E-nose)and GC-MS,respectively.The major volatile compounds were Maillard reaction products,which were not detected in the raw samples,and the terpene content decreased after roasting.A total of 13 odor-active compounds analyzed by GC-O were identified,with the majority having odor-active value(OAV)above 1.This study provides an aroma profile of PSO that can be used as a primary database for controlling the aroma and selecting optimal roasting conditions for application in food processing.展开更多
Based on a three-stage fermented glutinous rice wine(GRW)dough procedure,Chinese steamed bread(GRWCSB)could be well prepared.This work systematically investigated the effects of stage II-mash and liquid fermentation(M...Based on a three-stage fermented glutinous rice wine(GRW)dough procedure,Chinese steamed bread(GRWCSB)could be well prepared.This work systematically investigated the effects of stage II-mash and liquid fermentation(MLF)and dough fermentation on flavor compounds and development.The MLF system,directly applicable for GRW-CSB(identified as MLF-CSB)preparation without yeast addition,was separated into the supernatant fraction(SF)and the microbial fraction(MF).Then SF-CSB and MF-CSB were derived and prepared with different strategies.Quantitative descriptive analysis(QDA)and electronic tongue analysis indicated that the MLF-CSB demonstrated significant flavor advantages compared to the yeast-leavened CSB(Y-CSB),with bitterness and sourness intensity reduced by 72.8%and 51.1%,respectively,while wheat aroma and fruity aroma increased by 50.9%and 47.5%,respectively.Notably,SPME-GC-MS identified 53 volatile compounds in MLF-CSB,with alcohols,aldehydes,and esters markedly exceeding Y-CSB(p<0.05).(E)-2-nonenal(OAV=25.1)and 1-octen-3-ol(OAV=16.2)were identified as key aroma contributors in MLF-CSB.SF-CSB exhibited flavor profiles closely resembling those of MLF-CSB,demonstrating that SF incorporation substantially enhanced umami and fruity aromas.More importantly,the dough fermentation process also played a pivotal role in flavor development,where extending fermentation duration from 2 h to 4 h caused a 77.3%elevation of volatile compounds in Y-CSB,compared to only a 7.1%increment in SF-CSB.These findings clarify the mechanisms underlying MLF-CSB flavor superiority and highlight the potential of SF as a natural flavor enhancer.展开更多
Red sour soup(RSS)is a fermented food characterized by its distinctive aroma and broad market potential;however,its flavor profile has not yet been thoroughly investigated.In this study,three extraction techni-ques-so...Red sour soup(RSS)is a fermented food characterized by its distinctive aroma and broad market potential;however,its flavor profile has not yet been thoroughly investigated.In this study,three extraction techni-ques-solid-phase microextraction(SPME),solvent-assisted flavor evaporation(SAFE),and dual mode unity solid-phase microextraction(DMU-SPME)-were combined with gas chromatography-mass spectrometry(GC-MS)to identify 177 volatile compounds.Gas chromatography-olfactometry(GC-O)coupled with aroma extract dilution analysis(AEDA)further screened 84 aroma-active compounds.Quantification using the external standard method revealed that 36 aroma compounds exhibited odor activity values(OAVs)greater than 1.Aroma omission and recombination experiments demonstrated that 30 key aroma compounds significantly contributed to the overall aroma of RSS.Among these,ethyl hexanoate,linalool,eugenol,sulfur-containing compounds,nonanal,and guaiacol were identified as major contributors to the unique flavor characteristics of RSS.This study provides a valuable reference for both aroma research and industrial production of RSS,while also establishing a foundation for flavor studies of complex food matrices.展开更多
To acquire candidate non-Saccharomyces strains for preparation of high-quality Vidal icewine,11 representative indigenous non-Saccharomyces strains were selected for analyzing their production of organic acids,phenoli...To acquire candidate non-Saccharomyces strains for preparation of high-quality Vidal icewine,11 representative indigenous non-Saccharomyces strains were selected for analyzing their production of organic acids,phenolic compounds,aroma-active compounds and evaluating their sensory profile in Vidal juice.The results showed that the contents of organic acids in the wines were controlled and balanced well by the non-Saccharomyces strains as well as polyphenol concentrations were well improved during the fermentation.The strains differed from each other in their ability to produce aroma compounds,causing diversity and complexity of aroma characteristics in wine.Fermentation by Saccharomycopsis crataegensis YC30(Sc)and Hanseniaspora uvarum QTX22(Hu)could enhance the sweet and floral notes in Vidal icewine,especially Sc,which has never been reported before.It can not only enrich the aroma categories,but also increase the content ofδ-decalactone,γ-decalactone,ethyl isobutyrate,ethyl butyrate,phenethyl acetic acid,etc.The evaluation and optimization of non-Saccharomyces yeast strains could provide theoretical basis for the improvement of ice wine quality,and supply new ideas and strategies for the brewing of ice wine.展开更多
Many dormitories have a high population density,and occupants exposed to volatile organic compounds(VOCs)could suffer severe physical and mental issues,so it is important to ensure good indoor air quality(IAQ).Current...Many dormitories have a high population density,and occupants exposed to volatile organic compounds(VOCs)could suffer severe physical and mental issues,so it is important to ensure good indoor air quality(IAQ).Currently,indoor VOC analysis using only chemical concentration cannot accurately reflect the effect of odor on human comfort.Therefore,the sensory evaluation of indoor odor acts as a supplementary method for an IAQ assessment.Here,we measured indoor VOC concentrations in 10 dormitories under occupied and unoccupied conditions.The contribution of building materials and human-related emissions was analyzed.An odor activity value(OAV)was calculated using the VOC concentration and odorant threshold.In addition,recruited sensory odor panel members assessed the odor intensity of each dormitory and the correlation between odor intensity and chemical measurements was analyzed.The indoor total VOC(TVOC)concentration under occupied conditions ranged from 242.2 to 1063.1μg/m^(3),with a mean value of 454.1μg/m^(3).The TVOC concentration under unoccupied conditions varied from 97.2 to 1055.2μg/m^(3),with a mean value of 342.2μg/m^(3).The TVOC concentration of 90% of the dormitories under the two conditions met the national IAQ standards.An average of 53.6% indoor TVOC emissions are related to building materials,the outdoor-related TVOC concentration accounts for 15.7%,and the average human-related TVOC emissions are 1519.4μg/(h·person),which accounts for 30.7%.Compared to TVOC concentration,odor intensity-OAV(OAV_(sum),OAV_(max))could better characterize subjective and objective correlations.However,the goodness-of-fit is not satisfactory.Weber–Fencher's law has limitations in characterizing the correlation between odor intensity and OAV when applied to the indoor air mixture,based on this small-scale study.展开更多
Reservoir-induced earthquakes related with the construction of the Three Gorges Project have attracted great concerns of the public. Since the first water impoundment on May 25, 2003, a number of earthquakes have occu...Reservoir-induced earthquakes related with the construction of the Three Gorges Project have attracted great concerns of the public. Since the first water impoundment on May 25, 2003, a number of earthquakes have occurred during the water storage stages, in which the largest was the Badong M5.1 earthquake on December 16, 2013. In this paper, the relationships between seismic activities, b value, seismic parameters, and reservoir water level fluctuations are studied. In addition, based on the digital seismic waveform data obtained since 2000, the focal depth changes and focal mechanism characteristics before and after the water impoundment are studied as well. These provide us important information to understand the earthquake mechanisms. The results show that these earthquakes are typical reservoir-induced earthquakes, which are closely related to water infiltration, pore pressure, and water level fluctuations.The majority of the micro and small earthquakes are caused by karst collapse, mine collapse, bank reformation, superficial unloading, and so on. The larger earthquakes are related to the fault structures to some extent. Due to the persistent effects of water impoundment on the seismic and geological environments around the reservoir and water infiltration into the rocks, the influences on the crustal deformation field, gravity field, seepage field, and fault medium-softening action may vary gradually from a higher strength to a weaker one. Therefore, it is possible that small earthquakes and few medium earthquakes(M≤5.5) will occur in the reservoir area in the future.展开更多
This study evaluated and compared the fermentative and flavor properties of Hericium erinaceus and Tremella fuciformis fermented beverage(HTFB)produced by four commercial lactic acid bacteria(LAB),i.e.,L.plantarum,L.r...This study evaluated and compared the fermentative and flavor properties of Hericium erinaceus and Tremella fuciformis fermented beverage(HTFB)produced by four commercial lactic acid bacteria(LAB),i.e.,L.plantarum,L.rhamnosus,L.paracasei or S.thermophilu s.All four strains showed the probiotic potential of utilizing Hericium erinaceus and Tremella fuciformis as fermentation substrates.Among four LAB,L.plantarum produced significantly highest concentrations of total acids(76.16 g/L),while the viable count of HTFB inoculated with L.paracasei was the highest(7.18 log CFU/mL).The contents of bioactive components such as polyphenols and triterpenoids significantly increased after fermentation regardless of the strains.The fermentation process enriched the volatile profile and reduced the unpleasant flavors such as nonanal and 1-octen-3-ol.According to the relative odor activity values and PLS-DA analysis,a total of 8 volatile organic compounds were identified as markers with odor contributions.Furthermore,the olfactory characteristics of the four beverages could be clearly distinguished by electronic nose.The electronic tongue results showed that the fermentation process increased the sourness and decreased the bitterness and astringency of the beverage,resulting in an improved taste property.The sensory evaluation finally confirmed that HTFB inoculated with L.paracasei was the most acceptable product to consumers with high overall flavor coordination.Overall,this work provided valuable information for the selection of premium fermentation strains to produce fermented edible fungi beverages with better nutritional and sensory qualities.展开更多
基金funded by Shaanxi Natural Science Foundation (2019JQ-665)Xi’an Agricultural Science and Technology Project (20NYYF0021)supported by the Open Project Program of Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University (BTBU), Beijing 100048, China (SPFW2020YB12)
文摘P omegranate(Punica granatum L.)has attracted considerable attention in world markets due to its valuable nutrients and highly appreciated sensory properties.The aroma profiles of 4 varieties of pomegranate juice,including Dahongtian(DP),Jingpitian(JP),Luyudan(LP),and Tianhonngdan(TP),were investigated via gas chromatography-mass spectrometry(GC-MS)and gas chromatography-olfactometry(GC-O)analyses.A total of 43 volatile compounds were identified by using GC-MS.Among these compounds,16 were considered as potential aroma-active compounds as detected by GC-O.These compounds belonged to the classes of terpinenes,alcohols,and aldehydes.Eleven volatile compounds were defined as the main contributors to the overall aroma of pomegranate juice due to their high odor activity values(OAVs≥1).Aroma recombination and omission tests confirmed thatβ-myrcene,1-hexanol,and(Z)-3-hexen-1-ol were the key aroma compounds,and limonene,1-octen-3-ol,linalool,and hexanal were important aroma-active compounds in DP samples.
文摘In the present work,the fruits of four Morus species,namely Morus alba (white mulberry),Morus nigra (black mulberry),Morus laevigata (large white fruit),and Morus laevigata (large black fruit),were analyzed for proximate composition,essential minerals,and antioxidant potentials.For this purpose,the ripe fruits were collected from the northern regions of Pakistan.The major nutritional components moisture,ash,lipids,proteins,fibres,carbohydrates,and total sugar) were found to be in the suitable range along with good computed energy.Total dry weight,pH,and titratable acidity (percent citric acid) were (17.60±1.94)–(21.97±2.34) mg/100 g,(3.20±0.07)–(4.78±0.15),and (0.84±0.40)%–(2.00±0.08)%,respectively.Low riboflavin (vitamin B2) and niacin (vitamin B3) contents were recorded in all the fruits,while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW).The mulberry fruits were rich with regard to the total phenol and alkaloid contents,having values of (880±7.20)–(1650±12.25) mg/100 g FW and (390±3.22)–(660±5.25) mg/100 g FW,respectively.Sufficient quantities of essential macro-(K,Ca,Mg,and Na) and micro-(Fe,Zn,and Ni) elements were found in all the fruits.K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g,while Ca,Na,and Mg contents were (440±3.21)–(576±7.37),(260±3.86)–(280±3.50),and (240±3.51)–(360±4.20) mg/100 g,respectivly.The decreasing order of micro-minerals was Fe>Zn>Ni.The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits.Based on the results obtained,mulberry fruits were found to serve as a potential source of food diet and natural antioxidants.
文摘Cost problem is always a bottleneck which ties to the development and the competition ability in the enterprise of our country, especially in state-owned enterprise. Practice proves that traditional cost control can not satisfy the needs of enterprises. Enterprises are seeking better cost control approach with great efforts in order to calculate and control cost more accurately, and require cost control system has more strong functions. This paper analyzes value chain based cost control approach, and applies the gray relevancy analysis to the approach rightly.
文摘A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.
基金The work was supported bythe public welfare programofthe Ministry of Science and Technology of China (2004DIA3J010)the special preparatoryresearch of national keyfun-damental research project (2002CCD01700)the Young Scientists Funds of Institute of Earthquake Science , CEA(QN200401) .
文摘Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.
基金Supported by the National High Technology Research and Development Program of China(2006BAD05A03)~~
文摘μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied. The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M. longissimus during earlier aging periods compared with conventional chilling. But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain. The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities.
基金financially supported by the National First-Class Discipline Program of Food Science and Technology (JUFSTR20180202)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_1852)+1 种基金National Natural Science Foundation of China (31901728)Jiangsu Planned Projects for Postdoctoral Research Funds (2020Z297)
文摘The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break-in(3.5%-7.5%of total polar compounds(TPC)),optimum(7.5%-22.18%of TPC),and degrading stages(above 22.18%of TPC).Further,in order to distinguish the key aroma compounds in each stage,the FFs prepared in RO at TPC of 3.5%(FF4),14.5%(FF15),and 26.96%(FF27)and their relevant oils(RO4,RO15,RO27)were selected for sensory-directed analysis.The results revealed that the FF4 had low contents of(E,E)-2,4-decadienal(deep-fried odor)which also caused lower sensory score in FF4 sample.The higher contents of(E,E)-2,4-decadienal in FF15 induced its higher deep-fried odor.The FF27 had higher hexanoic acid(sweaty odor),heptanoic acid,nonanoic acid,benzene acetaldehyde(stale odor),and trans-4,5-epoxy-(E)-2-decenal(metallic odor)compared with FF4 and FF15,thus leading to the undesirable flavor of FF27.Moreover,the decrease of 2,5-dimethylpyrazine and 2-ethyl-6-methyl-pyrazine in FF27 induced the lower roasty flavor,which may also lead to the decline of the sensory score.Similarly,the higher contents of(E)-2-undecenal,hexanoic acid,heptanoic acid,and nonanoic acid in RO27 lead to increase its rancid score and thus lower the sensory score.
基金the financial support from Research Institute Technology Development Special Fund of Ministry of Science and Technology(No.2012EG11120)
文摘A series of long-chain quaternary ammonium hydroxides were synthesized from tertiary amines and confirmed by ~1H NMR and FTIR.Surface properties and pH of these surfactants were investigated.The critical micelle concentrations（CMC） of the synthesized quaternary ammonium hydroxides are lower than the conventional quaternary ammonium surfactants.The micelles shapes of these long-chain quaternary ammonium hydroxides in aqueous solution are spherical at a concentration of 0.1 mol/L.The pH values of the synthesized quaternary ammonium hydroxides are 12.25-12.51.
基金supported by the taishan Industrial Experts Program and the Yuandu Industry Leading talents Project.
文摘Radish is a root vegetable with significant nutritional and economic value.However,there is limited information on the flavor and taste profiles of different radish varieties.In this study,headspace gas chromatography-ion mobility spectrometry was used to investigate the characteristic volatile compounds in Weixian green radish,establishing its volatile compound fingerprint.Further,its volatile compound composition was compared with those of other radish varieties.A total of 46 compounds were identified in the Weixian green radish,including 19 aldehydes,six alcohols,five esters,six ketones,three furans,three pyrazines,and four other compounds.Among different radish varieties,the Weixian radish contained the largest number of volatile compounds,followed by hybrid and green-root radish samples.Flavor differences among the different radish varieties were mainly affected by the type and content of esters,aldehydes,and ketones,among which 1-nonanal,propanal,1-penten-3-one,and isobutyric acid methyl ester were the key flavor contributors.This study not only reveals the differences in the flavor compounds between different radish varieties but also provides a scientific basis for the geographical protection of varieties and market positioning of radishes in Weixian County.
基金supported by Key Research and Development Program of Shaanxi Province(Grant No.2022NY-022)National Natural Science Foundation of China(31601436)。
文摘To explore a novel producing strategy for enhancing antioxidant activity and aroma of low-ethanol kiwi wine,kiwifruit juice was sequential fermentation with indigenous Zygosaccharomyces rouxii(Zr)and Saccharomyces cerevisiae(Sc)without adding sugars.The organic acids,bioactive compounds,volatile constituents,antioxidant capacities and sensory profiles were measured to evaluate the performance of different inoculation ratios.The results indicated that compared with pure fermentation of Sc,the sequential fermentations significantly increased the total flavonoids,total phenols,some mono-phenols and antioxidant activities of the low-ethanol kiwi wines,and resulted in a positive effect on organic acids mainly by reducing the content of malic acid.At the same time,sequential fermentations significantly enhanced the aroma profile of the low-ethanol kiwi wines.The higher inoculation ratio of Zr greatly increased the complexity of the volatiles,improving sweet odor of the wines.While the similar inoculation ratio of Zr and Sc significantly increased the volatile contents,intensifying the tropical fruity and kernel fruity.In addition,the partial least-squares regression analysis showed that aldehydes resulted in sourness,ethyl esters and acetate esters possessed a positive impact on tropical fruity and kernel fruity.
基金’Jinhua bergamot miniature potted variety breeding and cultivation technology research’(2021-2-028).
文摘Citri Sarcodactylis Fructus(CSF)has pharmacological effects such as anti-inflammatory and antihypertensive,and is widely used as medicine and tea.Due to the different physical and chemical properties of CSF from each growing area,we quickly distinguish CSF from different regions by determining the characteristic flavor.This study aimed to investigate the variations in volatile flavors of different CSF originating from Jinhua(JFC),Guangdong(GFC),and Yunnan(YFC).Sensory evaluation,combined with gas chromatography-ion mobility spectrometry(GC-IMS)and gas chromatography-mass spectrometry(GC-MS),was employed to analyze the volatiles of CSF.GC-IMS showed each sample exhibited its characteristic peak,with YFC demonstrating higher peak areas compared to the others.GC-MS showed that terpenes constituted the highest proportion of volatiles in CSF samples,with limonene andγ-terpinene being the major components in finger citron.Odor activity value(OAV)in combination with principal component analysis(PCA)demonstrated that specific compounds such as dimethyl anthranilate,1,3,8-p-menthatriene,2-undecanone,and geranyl propionate contributed significantly to the flavor profile of JFC.Similarly,α-Pinene,β-phellandrene,anethole,and meta-cymene played key roles in the flavor profile of GFC,whereas(Z)-β-ocimene,1,8-cineole,citronellol,6-methyl-5-hepten-2-one,β-ionone,and p-cymene were identified as characteristic flavor compounds of YFC.Sensory evaluation showed significant flavor distinctions among the three types of CSF,with JFC exhibiting a prominent fruit aroma,GFC showing an evident herbal flavor,and YFC possessing a distinct floral aroma in its overall profile.These findings provided information on the differentiation of CSF originating from various geographical regions at a molecular level.
基金supported by the Natural Science Foundation of Liaoning Province(2021-MS-299)the National Natural Science Foundation of China(31770725)the China Scholarship Council(CSC No.202008210171).
文摘Mulberry leaf tea(MLT),a traditional medicinal tea in Asia,is beloved by Chinese consumers for its unique sweet and mellow taste and its well-documented beneficial effects in combating metabolic diseases.Therefore,a comprehensive study on the aroma,flavor,and anti-NAFLD(nonalcoholic fatty liver disease)effects of MLT under different fermentation times using chromatography,statistics,and network pharmacology was conducted.A total of 110 volatile compounds and 25 non-volatile compounds were identified from three types of MLT samples and mulberry leaves.With the extension of fermentation time,the bitterness of MLT decreased significantly,and the aroma gradually changed from fresh to intense.Major aroma-contributing substances and 8 characteristic differential substances were screened using ROAV values and statistical analysis.The molecular docking predicted that the detected flavonoid glycosides have a high binding energy with bitter receptors and PRP,ranging from-4.4 to-7.9 kcal/mol.By combining this with practical analysis,it was concluded that the flavonoid glycosides may enhance the bitterness and astringency in mulberry leaves.The network pharmacology approach was used to conduct target network,GO pathway,and KEGG enrichment analysis on 13 potential substances with medicinal value,it is found that MLT mainly exerts its anti-NAFLD effect by regulating metabolism and cancer pathways.
基金supported by National Key Research&Development Program of China(2021YFD2100105)School-Enterprise Cooperation Project(2023-4201-13-000901).
文摘The key aroma compounds of five yeast extracts(YE)were identified comprehensively by solvent-assisted flavor evaporation(SAFE),simultaneous distillation extraction(SDE)and solid-phase microextraction(HS-SPME)combined with sensomics approach and convolutional neural network(CNN)framework.The results found 349 volatiles via three methods,with 51 in common,highlighting their combined importance.Forty-nine aroma compounds(FD factor>27)were identified by aroma extract dilution analysis,of which 40 had OAV≥1.Five YEs contained 34,26,16,27,and 27 key aroma compounds respectively,sharing only seven:δ-dodecalactone,2,5-dimethylpyrazine,2-ethyl-6-methylpyrazine,dimethyl trisulfide,indole,benzaldehyde,and 2-methoxyphenol.Additionally,unique key aroma-active compounds for Y2 wereγ-undecalactone,2,3-diethylpyrazine and 2-naphthalenol,and for Y1,Y4 and Y5 were 2-formylpyrrole,4-methyl-pentanoic acid andα-angelica lactone.Roasted and meaty aromas originated from pyrazines,lactones and phenols were prominent sensory attributes of YE.The CNN model showed great fitting and prediction capabilities(91%training set accuracy,82%validation set accuracy at the 50th epoch),reflecting aroma characteristics of YE,with high similarity to results of OAV analysis results.This research combined different extraction methods with sensomics approach and CNN,providing profound insights into YE aroma compounds and thus helping to production of YEs with desirable aroma profiles.
基金supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education(NRF-2022R1I1A3066192).
文摘In this study,electronic sensors,gas chromatography-mass spectrometry(GC-MS),and GC-olfactometry(GC-O)were used to analyze the flavor of pomegranate seed oil(PSO)extracted from roasted pomegranate seeds.A preliminary study was conducted to determine the extent to which roasting treatment positively affects the physicochemical and sensory properties of pomegranate seeds,and a total of four conditions including raw were selected(raw,160℃for 15 min,160℃for 20 min,180℃for 10 min).This study aimed to determine if the beneficial effects of roasting seeds are retained when the oil is extracted from the seeds,and to explore their potential use in the food industry as a fat-soluble material.Electronic tongue(E-tongue)analysis revealed that roasting enhanced umami and sweetness while reducing bitterness.A total of 46 and 50 volatile compounds were detected using the electronic nose(E-nose)and GC-MS,respectively.The major volatile compounds were Maillard reaction products,which were not detected in the raw samples,and the terpene content decreased after roasting.A total of 13 odor-active compounds analyzed by GC-O were identified,with the majority having odor-active value(OAV)above 1.This study provides an aroma profile of PSO that can be used as a primary database for controlling the aroma and selecting optimal roasting conditions for application in food processing.
基金funded by the program for the National Natural Science Foundation of China(No.32101988)the Postdoctoral Research Foundation of China(No.2019 M651706)+1 种基金supported by the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,Jiangnan Universitysupported by the Cross-Innovation Open Project of Food Flavor and Health,Beijing Technology and Business University.
文摘Based on a three-stage fermented glutinous rice wine(GRW)dough procedure,Chinese steamed bread(GRWCSB)could be well prepared.This work systematically investigated the effects of stage II-mash and liquid fermentation(MLF)and dough fermentation on flavor compounds and development.The MLF system,directly applicable for GRW-CSB(identified as MLF-CSB)preparation without yeast addition,was separated into the supernatant fraction(SF)and the microbial fraction(MF).Then SF-CSB and MF-CSB were derived and prepared with different strategies.Quantitative descriptive analysis(QDA)and electronic tongue analysis indicated that the MLF-CSB demonstrated significant flavor advantages compared to the yeast-leavened CSB(Y-CSB),with bitterness and sourness intensity reduced by 72.8%and 51.1%,respectively,while wheat aroma and fruity aroma increased by 50.9%and 47.5%,respectively.Notably,SPME-GC-MS identified 53 volatile compounds in MLF-CSB,with alcohols,aldehydes,and esters markedly exceeding Y-CSB(p<0.05).(E)-2-nonenal(OAV=25.1)and 1-octen-3-ol(OAV=16.2)were identified as key aroma contributors in MLF-CSB.SF-CSB exhibited flavor profiles closely resembling those of MLF-CSB,demonstrating that SF incorporation substantially enhanced umami and fruity aromas.More importantly,the dough fermentation process also played a pivotal role in flavor development,where extending fermentation duration from 2 h to 4 h caused a 77.3%elevation of volatile compounds in Y-CSB,compared to only a 7.1%increment in SF-CSB.These findings clarify the mechanisms underlying MLF-CSB flavor superiority and highlight the potential of SF as a natural flavor enhancer.
基金supported by the National Key R&D Program of China,Study on the formation mechanism and regulation technology of Chinese traditional and ethnic food quality,(2021YFD2100100).
文摘Red sour soup(RSS)is a fermented food characterized by its distinctive aroma and broad market potential;however,its flavor profile has not yet been thoroughly investigated.In this study,three extraction techni-ques-solid-phase microextraction(SPME),solvent-assisted flavor evaporation(SAFE),and dual mode unity solid-phase microextraction(DMU-SPME)-were combined with gas chromatography-mass spectrometry(GC-MS)to identify 177 volatile compounds.Gas chromatography-olfactometry(GC-O)coupled with aroma extract dilution analysis(AEDA)further screened 84 aroma-active compounds.Quantification using the external standard method revealed that 36 aroma compounds exhibited odor activity values(OAVs)greater than 1.Aroma omission and recombination experiments demonstrated that 30 key aroma compounds significantly contributed to the overall aroma of RSS.Among these,ethyl hexanoate,linalool,eugenol,sulfur-containing compounds,nonanal,and guaiacol were identified as major contributors to the unique flavor characteristics of RSS.This study provides a valuable reference for both aroma research and industrial production of RSS,while also establishing a foundation for flavor studies of complex food matrices.
基金This research was supported by the Science and Technology Plan Project of Shaanxi(No.K3310218103 and K3010220051)the Science and Technology Innovation Project of Ningxia Agriculture and Forestry Academy(No.NKYJ-20-01 and NGSB-2021-5-04)Ningxia Youth Science and Technology Talent Project(No.NXKJTJGC2020140).
文摘To acquire candidate non-Saccharomyces strains for preparation of high-quality Vidal icewine,11 representative indigenous non-Saccharomyces strains were selected for analyzing their production of organic acids,phenolic compounds,aroma-active compounds and evaluating their sensory profile in Vidal juice.The results showed that the contents of organic acids in the wines were controlled and balanced well by the non-Saccharomyces strains as well as polyphenol concentrations were well improved during the fermentation.The strains differed from each other in their ability to produce aroma compounds,causing diversity and complexity of aroma characteristics in wine.Fermentation by Saccharomycopsis crataegensis YC30(Sc)and Hanseniaspora uvarum QTX22(Hu)could enhance the sweet and floral notes in Vidal icewine,especially Sc,which has never been reported before.It can not only enrich the aroma categories,but also increase the content ofδ-decalactone,γ-decalactone,ethyl isobutyrate,ethyl butyrate,phenethyl acetic acid,etc.The evaluation and optimization of non-Saccharomyces yeast strains could provide theoretical basis for the improvement of ice wine quality,and supply new ideas and strategies for the brewing of ice wine.
基金supported by the National Natural Sciences Foundation of China(52278109).
文摘Many dormitories have a high population density,and occupants exposed to volatile organic compounds(VOCs)could suffer severe physical and mental issues,so it is important to ensure good indoor air quality(IAQ).Currently,indoor VOC analysis using only chemical concentration cannot accurately reflect the effect of odor on human comfort.Therefore,the sensory evaluation of indoor odor acts as a supplementary method for an IAQ assessment.Here,we measured indoor VOC concentrations in 10 dormitories under occupied and unoccupied conditions.The contribution of building materials and human-related emissions was analyzed.An odor activity value(OAV)was calculated using the VOC concentration and odorant threshold.In addition,recruited sensory odor panel members assessed the odor intensity of each dormitory and the correlation between odor intensity and chemical measurements was analyzed.The indoor total VOC(TVOC)concentration under occupied conditions ranged from 242.2 to 1063.1μg/m^(3),with a mean value of 454.1μg/m^(3).The TVOC concentration under unoccupied conditions varied from 97.2 to 1055.2μg/m^(3),with a mean value of 342.2μg/m^(3).The TVOC concentration of 90% of the dormitories under the two conditions met the national IAQ standards.An average of 53.6% indoor TVOC emissions are related to building materials,the outdoor-related TVOC concentration accounts for 15.7%,and the average human-related TVOC emissions are 1519.4μg/(h·person),which accounts for 30.7%.Compared to TVOC concentration,odor intensity-OAV(OAV_(sum),OAV_(max))could better characterize subjective and objective correlations.However,the goodness-of-fit is not satisfactory.Weber–Fencher's law has limitations in characterizing the correlation between odor intensity and OAV when applied to the indoor air mixture,based on this small-scale study.
基金supported by the National Natural Science Foundation of China (41572354)the Key Foundation of the Institute of Seismology (IS201616254)
文摘Reservoir-induced earthquakes related with the construction of the Three Gorges Project have attracted great concerns of the public. Since the first water impoundment on May 25, 2003, a number of earthquakes have occurred during the water storage stages, in which the largest was the Badong M5.1 earthquake on December 16, 2013. In this paper, the relationships between seismic activities, b value, seismic parameters, and reservoir water level fluctuations are studied. In addition, based on the digital seismic waveform data obtained since 2000, the focal depth changes and focal mechanism characteristics before and after the water impoundment are studied as well. These provide us important information to understand the earthquake mechanisms. The results show that these earthquakes are typical reservoir-induced earthquakes, which are closely related to water infiltration, pore pressure, and water level fluctuations.The majority of the micro and small earthquakes are caused by karst collapse, mine collapse, bank reformation, superficial unloading, and so on. The larger earthquakes are related to the fault structures to some extent. Due to the persistent effects of water impoundment on the seismic and geological environments around the reservoir and water infiltration into the rocks, the influences on the crustal deformation field, gravity field, seepage field, and fault medium-softening action may vary gradually from a higher strength to a weaker one. Therefore, it is possible that small earthquakes and few medium earthquakes(M≤5.5) will occur in the reservoir area in the future.
基金financially supported by Transformation Program of Scientific and Technological Achievements of Jiangsu Province(BA2021062).
文摘This study evaluated and compared the fermentative and flavor properties of Hericium erinaceus and Tremella fuciformis fermented beverage(HTFB)produced by four commercial lactic acid bacteria(LAB),i.e.,L.plantarum,L.rhamnosus,L.paracasei or S.thermophilu s.All four strains showed the probiotic potential of utilizing Hericium erinaceus and Tremella fuciformis as fermentation substrates.Among four LAB,L.plantarum produced significantly highest concentrations of total acids(76.16 g/L),while the viable count of HTFB inoculated with L.paracasei was the highest(7.18 log CFU/mL).The contents of bioactive components such as polyphenols and triterpenoids significantly increased after fermentation regardless of the strains.The fermentation process enriched the volatile profile and reduced the unpleasant flavors such as nonanal and 1-octen-3-ol.According to the relative odor activity values and PLS-DA analysis,a total of 8 volatile organic compounds were identified as markers with odor contributions.Furthermore,the olfactory characteristics of the four beverages could be clearly distinguished by electronic nose.The electronic tongue results showed that the fermentation process increased the sourness and decreased the bitterness and astringency of the beverage,resulting in an improved taste property.The sensory evaluation finally confirmed that HTFB inoculated with L.paracasei was the most acceptable product to consumers with high overall flavor coordination.Overall,this work provided valuable information for the selection of premium fermentation strains to produce fermented edible fungi beverages with better nutritional and sensory qualities.
