To obtain protease-and lipase-producing halotolerant/halophilic strains suitable for shrimp paste(SP)fermentation,the microbial community structure and enzyme-producing microbial species were analyzed and predicted us...To obtain protease-and lipase-producing halotolerant/halophilic strains suitable for shrimp paste(SP)fermentation,the microbial community structure and enzyme-producing microbial species were analyzed and predicted using metagenomics in 3 high-salt samples.Based on the linear salt gradient method,128 strains were screened.Eight halotolerant/halophilic strains highly producing 2 types of enzymes were identified and inoculated into lowsalt SP to assess the heterogeneity of SP.Physicochemical properties of SP indicated that Bacillus subtilis XJ-11,Virgibacillus halodenitrificans XJ-229,Piscibacillus halophilus XY-193,and Bacillus vallismortis HT-73 were more suitable for rapid fermentation of SP.Nutritional analysis showed that SP inoculated with V.halodenitrificans XJ-229 had the highest free amino acid content and SP inoculated with P.halophilus XY-193 had the highest unsaturated fatty acid content.The former had prominent umami,sweetness,and meaty aroma,weak bitterness and fishy flavor,and the closest flavor to the control(CP)based on sensory evaluation and E-nose analysis.A total of 61 volatile compounds were detected in all samples by SPME-GC-MS,of which 32,23,40,24,and 28 were detected in the CP and SP inoculated with B.subtilis XJ-11,V.halodenitrificans XJ-229,P.halophilus XY-193,and B.vallismortis HT-73,respectively,with 12,11,12,9,and 9 key flavor compounds.Among several samples,the highest levels of pyrazines,aldehydes,alcohols,and ketones were found in SP inoculated with B.subtilis XJ-11,V.halodenitrificans XJ-229,P.halophilus XY-193,and B.vallismortis HT-73,respectively.These results suggested that inoculation of different enzyme-producing halotolerant/halophilic strains resulted in differences in SP quality and main flavors.This study provides some references for process control and interpretation of heterogeneous mechanisms in low-salt SP fermented by inoculated strains.展开更多
Traditionally fermented shrimp paste has a long fermentation period and is susceptible of external factors,which leads to unstable quality and limits its development and application.Therefore,the purpose of this study...Traditionally fermented shrimp paste has a long fermentation period and is susceptible of external factors,which leads to unstable quality and limits its development and application.Therefore,the purpose of this study is to analyze the flavor changes in the shrimp paste fermentation process and screen out the key volatile aroma components in the shrimp paste to control the flavor quality of the shrimp paste products.The overall odor profile was detected by the electronic nose.A total of 106 volatile flavor compounds in the shrimp paste samples at different fermentation stages were identified by solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)and headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS).The main aroma components alcohols,aldehydes,pyrazines and other substances in the fermentation process showed an overall upward trend.A total of 17 key volatile aroma components in shrimp paste at different fermentation stages were identified by the relative aroma activity value(ROAV)method.The combination of electronic nose,SPME-GC-MS and HS-GC-IMS could comprehensively reflect the changes of volatile components in shrimp paste at different fermentation stages,which helps to further understand the mechanism of shrimp paste flavor formation and provides a basis for the regulation of the flavor quality of shrimp paste products.展开更多
Flavor characteristics of raw shrimp,high-salt and low-salt shrimp paste were evaluated and compared by sensory analysis,headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)and solid-phase microextraction...Flavor characteristics of raw shrimp,high-salt and low-salt shrimp paste were evaluated and compared by sensory analysis,headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)and solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS).In addition,aroma profiles and aroma-active compounds in these three samples were analyzed by solvent-assisted flavor evaporation-gas chromatography-olfactometry-mass spectrometry(SAFE-GC-O-MS).Results of sensory evaluation revealed that these three samples showed significant differences in sensitivity to the W2W,W2S,W1S and W1W sensors of the electronic nose(p<0.05),which represent organic sulfides,alkane aromatic compounds,short chain alkanes,and sulfides,respectively.Assessment of sensory parameters indicated tha high-salt shrimp paste had a strong roasted and meaty aroma,while low-salt shrimp paste showed an umami aroma more similar to raw shrimp.A total of 118 volatile compounds were identified using the three afore-mentioned gas chromatography methods.Among them,37 aroma-active compounds were detected by GC-O.High-salt shrimp was shown to contain more acids,aldehydes and heterocyclic compounds,which resembled cheese,roasted and meaty aromas.In contrast,low-salt shrimp paste contained more esters,which was similar to the umami aroma profile of raw shrimp.Interestingly,pyrazines were only produced in fermented shrimp paste samples,suggesting that they were produced during the fermentation process and they may contribute unique roasted and meaty aromas,which were important for the overall aroma characteristics of shrimp paste.展开更多
To study the changes of volatile compounds and antioxidant activity of fast fermented shrimp head paste during the fermentation processing,Penaeus vannamei boone head was used as the raw material,and compound starter ...To study the changes of volatile compounds and antioxidant activity of fast fermented shrimp head paste during the fermentation processing,Penaeus vannamei boone head was used as the raw material,and compound starter was added for fermen-tation.During the 14 days of fermentation,the changes of free amino acids,volatile flavor compounds and main components were determined by SPME-GC-MS and electronic nose.The oxidation-resistance changes of water extract at different fermentation stages were evaluated.The results showed that the total free amino acids increased from original 2320 to 5640 mg(100 mL)^(−1).SPME-GC-MS analysis found that aldehydes,pyrazine compounds increased from 10.80%,1.94%to 24.35%,13.63%respectively during the fermentation process.The HO·scavenging ability of shrimp head paste increased from 52%to 86%.Our results showed that the shrimp paste produced from shrimp head fermentation could obtain good flavor and possess certain antioxidant activity of aquatic fermented condiment.展开更多
基金supported by the National Natural Science Foundation of China(22138004)Shaoxing Science and Technology Plan Project(2022B43001,2023B43001).
文摘To obtain protease-and lipase-producing halotolerant/halophilic strains suitable for shrimp paste(SP)fermentation,the microbial community structure and enzyme-producing microbial species were analyzed and predicted using metagenomics in 3 high-salt samples.Based on the linear salt gradient method,128 strains were screened.Eight halotolerant/halophilic strains highly producing 2 types of enzymes were identified and inoculated into lowsalt SP to assess the heterogeneity of SP.Physicochemical properties of SP indicated that Bacillus subtilis XJ-11,Virgibacillus halodenitrificans XJ-229,Piscibacillus halophilus XY-193,and Bacillus vallismortis HT-73 were more suitable for rapid fermentation of SP.Nutritional analysis showed that SP inoculated with V.halodenitrificans XJ-229 had the highest free amino acid content and SP inoculated with P.halophilus XY-193 had the highest unsaturated fatty acid content.The former had prominent umami,sweetness,and meaty aroma,weak bitterness and fishy flavor,and the closest flavor to the control(CP)based on sensory evaluation and E-nose analysis.A total of 61 volatile compounds were detected in all samples by SPME-GC-MS,of which 32,23,40,24,and 28 were detected in the CP and SP inoculated with B.subtilis XJ-11,V.halodenitrificans XJ-229,P.halophilus XY-193,and B.vallismortis HT-73,respectively,with 12,11,12,9,and 9 key flavor compounds.Among several samples,the highest levels of pyrazines,aldehydes,alcohols,and ketones were found in SP inoculated with B.subtilis XJ-11,V.halodenitrificans XJ-229,P.halophilus XY-193,and B.vallismortis HT-73,respectively.These results suggested that inoculation of different enzyme-producing halotolerant/halophilic strains resulted in differences in SP quality and main flavors.This study provides some references for process control and interpretation of heterogeneous mechanisms in low-salt SP fermented by inoculated strains.
基金support from the National Key R&D Program of China (2019YFD0901903)the Innovation Team Project of Hebei (Province) Modern Agricultural Industry Technology System (HBCT2018170207)the Postgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX20_1426)
文摘Traditionally fermented shrimp paste has a long fermentation period and is susceptible of external factors,which leads to unstable quality and limits its development and application.Therefore,the purpose of this study is to analyze the flavor changes in the shrimp paste fermentation process and screen out the key volatile aroma components in the shrimp paste to control the flavor quality of the shrimp paste products.The overall odor profile was detected by the electronic nose.A total of 106 volatile flavor compounds in the shrimp paste samples at different fermentation stages were identified by solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)and headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS).The main aroma components alcohols,aldehydes,pyrazines and other substances in the fermentation process showed an overall upward trend.A total of 17 key volatile aroma components in shrimp paste at different fermentation stages were identified by the relative aroma activity value(ROAV)method.The combination of electronic nose,SPME-GC-MS and HS-GC-IMS could comprehensively reflect the changes of volatile components in shrimp paste at different fermentation stages,which helps to further understand the mechanism of shrimp paste flavor formation and provides a basis for the regulation of the flavor quality of shrimp paste products.
基金supported by the National Natural Science Foundation of China[grant numbers 32072348,31671825].
文摘Flavor characteristics of raw shrimp,high-salt and low-salt shrimp paste were evaluated and compared by sensory analysis,headspace-gas chromatography-ion mobility spectrometry(HS-GC-IMS)and solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS).In addition,aroma profiles and aroma-active compounds in these three samples were analyzed by solvent-assisted flavor evaporation-gas chromatography-olfactometry-mass spectrometry(SAFE-GC-O-MS).Results of sensory evaluation revealed that these three samples showed significant differences in sensitivity to the W2W,W2S,W1S and W1W sensors of the electronic nose(p<0.05),which represent organic sulfides,alkane aromatic compounds,short chain alkanes,and sulfides,respectively.Assessment of sensory parameters indicated tha high-salt shrimp paste had a strong roasted and meaty aroma,while low-salt shrimp paste showed an umami aroma more similar to raw shrimp.A total of 118 volatile compounds were identified using the three afore-mentioned gas chromatography methods.Among them,37 aroma-active compounds were detected by GC-O.High-salt shrimp was shown to contain more acids,aldehydes and heterocyclic compounds,which resembled cheese,roasted and meaty aromas.In contrast,low-salt shrimp paste contained more esters,which was similar to the umami aroma profile of raw shrimp.Interestingly,pyrazines were only produced in fermented shrimp paste samples,suggesting that they were produced during the fermentation process and they may contribute unique roasted and meaty aromas,which were important for the overall aroma characteristics of shrimp paste.
基金supported by the National Na-tural Science Foundation of China(Nos.32072348 and 31671825)the Open Project Program of Beijing Key Laboratory of Flavor Chemistry(No.SPFW2019YB01).
文摘To study the changes of volatile compounds and antioxidant activity of fast fermented shrimp head paste during the fermentation processing,Penaeus vannamei boone head was used as the raw material,and compound starter was added for fermen-tation.During the 14 days of fermentation,the changes of free amino acids,volatile flavor compounds and main components were determined by SPME-GC-MS and electronic nose.The oxidation-resistance changes of water extract at different fermentation stages were evaluated.The results showed that the total free amino acids increased from original 2320 to 5640 mg(100 mL)^(−1).SPME-GC-MS analysis found that aldehydes,pyrazine compounds increased from 10.80%,1.94%to 24.35%,13.63%respectively during the fermentation process.The HO·scavenging ability of shrimp head paste increased from 52%to 86%.Our results showed that the shrimp paste produced from shrimp head fermentation could obtain good flavor and possess certain antioxidant activity of aquatic fermented condiment.
