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 fer...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.展开更多
This research was aimed at isolating and identifying the predominant lactic acid bacteria(LAB) in the traditional Chinese salt-fermented soybean food,douchi,from Yunnan,China.The predominant LAB present were isolated ...This research was aimed at isolating and identifying the predominant lactic acid bacteria(LAB) in the traditional Chinese salt-fermented soybean food,douchi,from Yunnan,China.The predominant LAB present were isolated and identified by conventional culture-dependent methods combined with molecular biological methods.Two hundred and sixty isolates were obtained from thirty kinds of traditional fermented douchi from six cities and counties in Yunnan,and those strains were divided into twelve groups by their morphological and biochemical characteristics.Based on 16S ribosomal DNA(rDNA) sequencing and analysis,56 representative strains were identified as belonging to 6 genera and 14 species:Lactobacillus(4 spp.),Weissella(3 spp.),Pediococcus(2 spp.),Staphylococcus(2 spp.),Enterococcus(1 sp.),and Bacillus(2 spp.).The results show that douchi contains a large natural population of LAB of diverse composition from which some strains could be selected as starters for functional fermented foods.This is the first study on the original douchi from Yunnan,and the results suggest that it may be a useful source for the isolation of LAB.This study has also laid a foundation for further research on developing functional douchi products.展开更多
Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide at- tention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic ag...Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide at- tention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic agents warrant investigation. In this study, 8 fibrinolytic enzyme-producing strains were isolated from Douchi--a traditional Chinese food, and strain XY-1 which produced the largest amount of the enzyme was chosen for the following experiments. The enzyme produced by strain XY-1 was named Douchi fibrinolytic enzyme （DFE）. We optimized the liquid culture medium of strain XY-1 for enzyme production using Plackett-Burman and Box-Behnken design. The predicted maximal DFE yield was 19.78 FU/mL with 11.4 g/L peptone, 0.5 g/L magnesium sulfate and 1 g/L sodium chloride. How- ever, we acquired maximal production of 21.33 FU/mL in actual experiments, equal to 107.84% of the theoretical value, and the yield had been increased by 79.55% as compared to the yield of un-optimized culture. It was demonstrated that the combined use of Plackett-Burman design and response surface methodology in fermentation optimization can effectively and rapidly increase DFE production.展开更多
Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of iso...Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.展开更多
[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products. [Method] The Douchi flbrinolytic enzyme producing strain was screened on the selected medium prepar...[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products. [Method] The Douchi flbrinolytic enzyme producing strain was screened on the selected medium prepared with self-made pork blood powder, the strain with the highest activity was screened out according to the size of hydrolysis cycle, and then preserved in LB medium. [ Rebait] A Douchi fibrinolytic enzyme producing strain with high thrombolytic activity was successfully screened out from the Douchi produced in Hunan, Guangdong and Jiangxi Prov- inces. [ Ceadusioe] The study lays foundation for the development of new-type thrombolytic drugs.展开更多
基金supported by Special key project of technological innovation and application development in Yongchuan District,Chongqing(2021yc-cxfz20002)the special funds of central government for guiding local science and technology developmentthe funds for the platform projects of professional technology innovation(CSTC2018ZYCXPT0006).
文摘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.
基金Project supported by the State Key Laboratory of Food Science and Technology of Jiangnan University (No.SKLF-KF-200805)the Yunnan Provincial Science and Technology Department (No.KKSA200926038),China
文摘This research was aimed at isolating and identifying the predominant lactic acid bacteria(LAB) in the traditional Chinese salt-fermented soybean food,douchi,from Yunnan,China.The predominant LAB present were isolated and identified by conventional culture-dependent methods combined with molecular biological methods.Two hundred and sixty isolates were obtained from thirty kinds of traditional fermented douchi from six cities and counties in Yunnan,and those strains were divided into twelve groups by their morphological and biochemical characteristics.Based on 16S ribosomal DNA(rDNA) sequencing and analysis,56 representative strains were identified as belonging to 6 genera and 14 species:Lactobacillus(4 spp.),Weissella(3 spp.),Pediococcus(2 spp.),Staphylococcus(2 spp.),Enterococcus(1 sp.),and Bacillus(2 spp.).The results show that douchi contains a large natural population of LAB of diverse composition from which some strains could be selected as starters for functional fermented foods.This is the first study on the original douchi from Yunnan,and the results suggest that it may be a useful source for the isolation of LAB.This study has also laid a foundation for further research on developing functional douchi products.
基金supported by a grant from the Ministry of Environmental Protection (No. 200909036)
文摘Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide at- tention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic agents warrant investigation. In this study, 8 fibrinolytic enzyme-producing strains were isolated from Douchi--a traditional Chinese food, and strain XY-1 which produced the largest amount of the enzyme was chosen for the following experiments. The enzyme produced by strain XY-1 was named Douchi fibrinolytic enzyme （DFE）. We optimized the liquid culture medium of strain XY-1 for enzyme production using Plackett-Burman and Box-Behnken design. The predicted maximal DFE yield was 19.78 FU/mL with 11.4 g/L peptone, 0.5 g/L magnesium sulfate and 1 g/L sodium chloride. How- ever, we acquired maximal production of 21.33 FU/mL in actual experiments, equal to 107.84% of the theoretical value, and the yield had been increased by 79.55% as compared to the yield of un-optimized culture. It was demonstrated that the combined use of Plackett-Burman design and response surface methodology in fermentation optimization can effectively and rapidly increase DFE production.
基金Supported by the Youth Fund Project from Beijing Academy of Agricultural and Forestry Sciences(QNJJ202001)。
文摘Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.
文摘[Objective] To isolate and preserve a high-activity Douchi fibrinolytic enzyme producing strain from Douchi products. [Method] The Douchi flbrinolytic enzyme producing strain was screened on the selected medium prepared with self-made pork blood powder, the strain with the highest activity was screened out according to the size of hydrolysis cycle, and then preserved in LB medium. [ Rebait] A Douchi fibrinolytic enzyme producing strain with high thrombolytic activity was successfully screened out from the Douchi produced in Hunan, Guangdong and Jiangxi Prov- inces. [ Ceadusioe] The study lays foundation for the development of new-type thrombolytic drugs.
