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1.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 50(5): 714-719, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31762243

RESUMO

OBJECTIVE: To select and identify the bacterium which highly produces protease and ß-D-glucosidase from 72 strains of Shuidouchi from Sichuan, and to provide evidence for further research on its nutritional value and fermentation strain exploiting. METHODS: Casein degradation test and pNPG chemical test were applied respectively to detect the capacity to produce protease and ß-D-glucosidase of each strain. Characteristics of morphology, biochemistry, 16S rRNA and MALDI-TOF-MS were used to identify the fermentation strain, which genetic stability, curves of growth and enzyme producing were also obtained. RESULTS: The strain with the highest enzyme activity of ß-D-glucosidase (0.084 U/L) among the top 10 strains for producing protease was selected as the fermentation strain and was identified as Bacillus subtilis, which curves of growth and enzyme producing conformed as well. The result of genetic stability showed that capacity of enzyme producing was stable until the 10th generation. CONCLUSIONS: The fermentation strain which highly produced protease and ß-D-glucosidase was selected from 72 strains of shuidouchi from Sichuan and was identified as Bacillus subtilis.


Assuntos
Bacillus subtilis/enzimologia , Glucosidases/biossíntese , Peptídeo Hidrolases/biossíntese , Alimentos de Soja/microbiologia , China , Fermentação , RNA Ribossômico 16S
2.
Pediatrics ; 144(4)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31519792

RESUMO

BACKGROUND: In 2017, we conducted a multistate investigation to determine the source of an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections, which occurred primarily in children. METHODS: We defined a case as infection with an outbreak strain of STEC O157:H7 with illness onset between January 1, 2017, and April 30, 2017. Case patients were interviewed to identify common exposures. Traceback and facility investigations were conducted; food samples were tested for STEC. RESULTS: We identified 32 cases from 12 states. Twenty-six (81%) cases occurred in children <18 years old; 8 children developed hemolytic uremic syndrome. Twenty-five (78%) case patients ate the same brand of soy nut butter or attended facilities that served it. We identified 3 illness subclusters, including a child care center where person-to-person transmission may have occurred. Testing isolated an outbreak strain from 11 soy nut butter samples. Investigations identified violations of good manufacturing practices at the soy nut butter manufacturing facility with opportunities for product contamination, although the specific route of contamination was undetermined. CONCLUSIONS: This investigation identified soy nut butter as the source of a multistate outbreak of STEC infections affecting mainly children. The ensuing recall of all soy nut butter products the facility manufactured, totaling >1.2 million lb, likely prevented additional illnesses. Prompt diagnosis of STEC infections and appropriate specimen collection aids in outbreak detection. Child care providers should follow appropriate hygiene practices to prevent secondary spread of enteric illness in child care settings. Firms should manufacture ready-to-eat foods in a manner that minimizes the risk of contamination.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157 , Doenças Transmitidas por Alimentos/epidemiologia , Escherichia coli Shiga Toxigênica , Alimentos de Soja/microbiologia , Adolescente , Idoso , Criança , Creches/estatística & dados numéricos , Pré-Escolar , Infecções por Escherichia coli/microbiologia , Fast Foods/efeitos adversos , Fast Foods/microbiologia , Feminino , Manipulação de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Síndrome Hemolítico-Urêmica/microbiologia , Humanos , Lactente , Masculino , Recall e Retirada de Produto , Alimentos de Soja/efeitos adversos , Estados Unidos/epidemiologia
3.
J Food Sci ; 84(9): 2441-2448, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31429494

RESUMO

The purpose of the present study was to evaluate the volatile profile of Kedong sufu, which is a typical bacteria-fermented soybean product in China, using solid phase microextraction coupled to gas chromatography and mass spectrometry and to reveal the evolution and diversity of flavor substances for this specialty. A total of 75 compounds were identified, including 35 esters, 4 alcohols, 4 phenols, 4 aldehydes, 7 acids, 10 ketones, and 11 other compounds from sufu samples during ripening. Some volatile compounds increased with ripening time, especially hexadecenoic acid ethyl ester, methoxy acetic acid pentyl ester, benzene propanoic acid ethyl ester, ethyl 9-hexadecenoate, ethyl oleate, ethanol, 3-methyl-1-butanol, 5-methoxy-1-pentanol, and eugenol; these compounds enriched the flavors and provided the typical savory taste of Kedong sufu. PRACTICAL APPLICATION: This research elucidated the formation of flavor substances in sufu. For traditional fermented foods, this study provides a scientific basis for promoting the generation of typical flavor substances and for the precise determination of maturity time.


Assuntos
Aromatizantes/química , Alimentos de Soja/análise , Soja/química , Compostos Orgânicos Voláteis/química , Bactérias/metabolismo , China , Fermentação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Humanos , Microextração em Fase Sólida/métodos , Alimentos de Soja/microbiologia , Soja/metabolismo , Soja/microbiologia , Paladar
4.
Appl Microbiol Biotechnol ; 103(18): 7519-7535, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31378837

RESUMO

Bacillus subtilis natto is a GRAS bacterium. Nattokinase, with fibrinolytic and antithrombotic activities, is one of the major products of this organism. It is being gradually recognized that B. subtilis natto can also be used as a biosynthetic strain for vitamin K2, which has phenomenal benefits, such as effects in the prevention of cardiovascular diseases and osteoporosis along with antitumor effects. Knocking out of the aprN gene by homologous recombination could improve the redox potential and slightly increase the concentration of MK-7. By detecting the change in redox potential during the growth of B. subtilis natto, a good oxygen supply and state of the cell membrane were found to be beneficial to vitamin K2 synthesis. A two-step RSM was used to optimize the operation parameters and substrate concentration in the new residue-free fermentation culture. The optimal conditions for the residue-free medium and control were determined. The optimum concentrations of soybean flour, corn flour, and peptone were 78.9, 72.4, and 24.8 g/L, respectively. The optimum rotational speed and volume of the culture medium using a shaking flask were 117 rpm and 10%, respectively. The state and composition of the cell membranes were more stable when engineered bacteria were cultured in this residue-free fermentation medium. Finally, the concentration of MK-7 increased by 37% to 18.9 mg/L, and the fermentation time was shortened by 24 h.


Assuntos
Bacillus subtilis/enzimologia , Fermentação , Oxirredução , Alimentos de Soja/microbiologia , Vitamina K 2/análogos & derivados , Bacillus subtilis/genética , Biofilmes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Meios de Cultura/química , Recombinação Homóloga , Microbiologia Industrial , Subtilisinas/metabolismo , Vitamina K 2/metabolismo
5.
Food Chem Toxicol ; 133: 110729, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31381944

RESUMO

The present study aimed to develop a consortium of nutritive fermented food products, supplemented with phytochemicals, with reduced toxicological contents. We developed new flavored Doenjang products (protein rich) fermented with lotus, ginkgo, and garlic plant extract-based Meju (termed as EMD) as the starter culture and by using traditional Meju (termed as TMD), where these plant extracts were added later during the fermentation process. Fermented Doenjang samples were analyzed for reduced levels of biogenic amines (BAs), aflatoxins, and microbial hazards, (including Bacillus cereus) as well as for their nutritive contents and antioxidant potential, after varying periods of fermentation (0, 3, 6, 9 and 12 months). All Doenjang samples prepared using plant extracts and their mixtures (1% and 10%) showed desired reduction in B. cereus counts, BAs, aflatoxins, and other foodborne pathogens as well as showed potent antioxidant abilities, including phenolic/flavonoid contents. Based on the higher efficiency in reducing various toxicants, Ginkgo biloba leaf extract added TMD samples were selected for the development of Doenjang products as an innovative approach, with great potential to improve the quality and safety of soybean fermented products in the Korean market, offering enhanced health benefits and reduced risks of toxicity.


Assuntos
Aflatoxinas/análise , Carga Bacteriana , Aminas Biogênicas/análise , Extratos Vegetais/análise , Alimentos de Soja/análise , Bacillus cereus/isolamento & purificação , Linhagem Celular , Cor , Fermentação , Microbiologia de Alimentos/métodos , Qualidade dos Alimentos , Depuradores de Radicais Livres/análise , Alho/química , Ginkgo biloba/química , Humanos , Concentração de Íons de Hidrogênio , Coreia (Geográfico) , Lotus/química , Alimentos de Soja/microbiologia , Soja/química , Soja/microbiologia
6.
J Sci Food Agric ; 99(13): 5687-5695, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31150112

RESUMO

BACKGROUND: The quality of soy sauce is strongly affected by microorganisms and raw materials (defatted soybean or whole soybean). The present study investigated the effect of two types of fortified pattern, including inoculation with starters (Tetragenococcus halophilus combined with Zygosaccharomyces rouxii and Candida versatilis), and adding culture medium (saccharified rice flour solution), on the metabolite profiles and microbial community of soy sauce produced from defatted soybean (DP) and whole soybean (HD). Relationships between microbes and volatiles, and their interactions, were shown. RESULTS: The dominant metabolites differed in the soy sauce samples except for isoflavones. Alcohols and phenols were higher in DP moromi. Two classes of dominant esters, long-chain fatty acid esters (LFAE) and unsaturated-short-chain fatty acid esters (USFAE), were higher in HD moromi than DP. Weissella, Leuconostoc, and Aspergillus were the dominant microbes. Leuconostoc, and Aspergillus increased, and Weissella decreased in moromi inoculated with starters compared with a control. Similar changes to Leuconostoc were observed in moromi added culture medium. CONCLUSIONS: The microbes were responsible for the formation of volatiles. The intergeneric interactions with microbes were affected by fortified pattern. The effect of starters or culture medium on microbial community and metabolites of soy sauce depended on the raw material. © 2019 Society of Chemical Industry.


Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Microbiota , Alimentos de Soja/microbiologia , Soja/microbiologia , Álcoois/análise , Álcoois/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Candida/metabolismo , Enterococcaceae/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Fermentação , Fungos/classificação , Fungos/genética , Fungos/metabolismo , Fenóis/análise , Fenóis/metabolismo , Alimentos de Soja/análise , Soja/metabolismo , Zygosaccharomyces/metabolismo
7.
Food Chem ; 292: 81-89, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054696

RESUMO

How to effectively increase or decrease the ability of A. oryzae to produce enzymes was the key to improve the quality of soy sauce. However, multi-core property of A. oryzae resulted in genetic instability of the new strain. Here, A. oryzae 3.042-3 which can stably produce mononuclear spores was constructed based on A. oryzae 3.042. A. oryzae 3.042-3-c obtained by transformation of the fragment of cis-CreA into A. oryzae 3.042-3 exhibited genetic stability. The fragment containing the cis-acting and the promoter CreA from A. oryzae was connected to chromosome VII in A. oryzae 3.042-3-c. Compared with A. oryzae 3.042-3, the cellulase activity of A. oryzae 3.042-3-c was reduced by 50.5% and the pectinase activity was decreased by 10.0%. At the end of the soy sauce fermentation, the salt-free solid content of A. oryzae 3.042-3-c was higher 58.9% than that of A. oryzae 3.042-3. The kinds and contents of the flavor components of the soy sauce from the fermentation by A. oryzae 3.042-3-c were higher than those of the A. oryzae 3.042 and A. oryzae 3.042-3, especially in alcohols and esters. HEMF was only found in the soy sauce from A. oryzae 3.042-3-c. The results indicated that the new strain A. oryzae 3.042-3-c could improve the quality of soy sauce from the low-salt solid fermentation by decreasing enzyme activity of cellulase and pectinase.


Assuntos
Aspergillus oryzae/enzimologia , Proteínas Fúngicas/metabolismo , Alimentos de Soja/análise , Aspergillus oryzae/genética , Celulase/genética , Celulase/metabolismo , Cromossomos Fúngicos , Qualidade dos Alimentos , Proteínas Fúngicas/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Alimentos de Soja/microbiologia
8.
J Microbiol Biotechnol ; 29(2): 191-199, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30602270

RESUMO

We inoculated different combinations of three starter candidates of Bacillus licheniformis, Staphylococcus succinus, and Tetragenococcus halophilus, into sterilized soybeans to predict their contributions to volatile compounds production through soybean fermentation. Simultaneously, we added NaCl to soybean cultures to evaluate its effect on the volatile compounds profile. Cells in soybean cultures (1.5% NaCl) reached almost their maximum growth in a day of incubation, while cell growth was delayed by increasing NaCl concentration in soybean cultures. The dominance of B. licheniformis and S. succinus in the mixed culture of three starter candidates switched to T. halophilus as the NaCl concentration increased from 1.5% to 14% (w/w). Seventeen volatile compounds were detected from the control and starter candidate-inoculated soybean cultures with and without the addition of NaCl. Principal component analysis of these volatile compounds concluded that B. licheniformis and S. succinus made major contributions to producing a specific volatile compound profile from soybean cultures where both species exhibited good growth. 3-Hydroxybutan-2-one, butane-2,3-diol, and 2,3,5,6-tetramethylpyrazine are specific odor notes for B. licheniformis, and 3-methylbutyl acetate and 2-phenylethanol are specific for S. succinus. Octan-3-one and 3-methylbutan-1-ol were shown to be decisive volatile compounds for determining the involvement of S. succinus in the soybean culture containing 7% NaCl. 3-Methylbutyl acetate and 3-methylbutan-1-ol were also produced by T. halophilus during soybean fermentation at an appropriate level of NaCl. Although S. succinus and T. halophilus exhibited growth on the soybean cultures containing 14% NaCl, species-specific volatile compounds determining the directionality of the volatile compounds profile were not produced.


Assuntos
Bactérias/metabolismo , Microbiologia de Alimentos , Alimentos de Soja/microbiologia , Soja/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Fermentação , Concentração de Íons de Hidrogênio , Microbiota/efeitos dos fármacos , Análise de Componente Principal , Cloreto de Sódio/química , Cloreto de Sódio/farmacologia , Especificidade da Espécie , Compostos Orgânicos Voláteis/análise
9.
J Sci Food Agric ; 99(1): 219-225, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29855042

RESUMO

BACKGROUND: Excessive nitrite in food is potentially harmful to human health because of carcinogenic effects caused by its nitroso-derivatives. Douchi, which widely distributed throughout the country, is a traditional solid fermented soybean food with low nitrite content. RESULTS: In this study, bacteria which can degrade nitrite were isolated from Douchi and identified from their 16S rDNA sequences. Acinetobacter guillouiae, Acinetobacter bereziniae, Bacillus subtilis, Bacillus tequilensis, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus aryabhattai and Bacillus methylotrophicus were selected. It was shown that all strains were able to degrade nitrite to some extent, including Bacillus subtilis NDS1, which was able to degrade 99.41% of nitrite. The enzyme activities of these strains were determined at 24 and 48 h and were shown to correspond with their nitrite degradation rates. The strains were used to inoculate Jiangshui, a kind of traditional fermented vegetable from northwest China that often has a high nitrite content. Of the strains tested, Bacillus subtilis NDS1, Bacillus tequilensis NDS3, Acinetobacter bereziniae NDS4, Bacillus subtilis NDS6, and Bacillus subtilis NDS12 were able to degrade nitrite in Jiangshui more rapidly, with Acinetobacter bereziniae NDS4 degrading almost all nitrite in 48 h compared with 180 h of control. CONCLUSION: These results indicate that the selected strains have potential to be used as nitrite-degrading agents in food. © 2018 Society of Chemical Industry.


Assuntos
Acinetobacter/isolamento & purificação , Acinetobacter/metabolismo , Bacillus/isolamento & purificação , Bacillus/metabolismo , Nitritos/metabolismo , Alimentos de Soja/microbiologia , Acinetobacter/classificação , Acinetobacter/genética , Bacillus/classificação , Bacillus/genética , DNA Bacteriano/genética , Filogenia , RNA Ribossômico 16S/genética , Alimentos de Soja/análise , Verduras/química , Verduras/microbiologia
10.
Probiotics Antimicrob Proteins ; 11(1): 283-294, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29411244

RESUMO

The plasminogen-free fibrin plate assay method was used to isolate Bacillus subtilis MX-6, a strain with high production of nattokinase from Chinese douchi. The presence of aprN, a gene-encoding nattokinase, was verified with PCR method. The predicted amino acid sequence was aligned with homologous sequences, and a phylogenetic tree was constructed. Nattokinase was sublimated with ammonium sulfate, using a DEAE-Sepharose Fast Flow column, a CM-Sepharose Fast Flow column and a Sephadex G-75 gel filtration column. SDS-PAGE analysis indicated that the molecular weight of the purified nattokinase from Bacillus subtilis MX-6 was about 28 kDa. Fermentation of Bacillus subtilis MX-6 nattokinase showed that nattokinase production was maximized after 72 h; the diameter of clear zone reached 21.60 mm on the plasminogen-free fibrin plate. Nattokinase production by Bacillus subtilis MX-6 increased significantly after supplementation with supernatant I, supernatant II and soy peptone but decreased substantially after the addition of amino acids. This result indicated that the nattokinase production by B. subtilis MX-6 might be induced by soybean polypeptides. The addition of MgSO4 and CaCl2 increased B. subtilis MX-6 nattokinase production.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/biossíntese , Alimentos de Soja/microbiologia , Subtilisinas/biossíntese , Sequência de Aminoácidos , Bacillus/classificação , Bacillus/enzimologia , Bacillus/genética , Bacillus subtilis/química , Bacillus subtilis/classificação , Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sequência de Bases , Meios de Cultura/metabolismo , Fermentação , Filogenia , Alinhamento de Sequência , Soja/metabolismo , Soja/microbiologia , Subtilisinas/química , Subtilisinas/genética
11.
Food Chem ; 274: 510-517, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30372972

RESUMO

Alkaline protease was purified from Bacillus sp. ZJ1502 isolated from fermented bean curd and its enzymatic properties were investigated. The final purification fold and specific activity were 18.6 and 30,230 U/mg, respectively. The molecular weight was 14 kDa by SDS-PAGE. The optimal pH and temperature were 10.0 and 40 °C, respectively. Alkaline protease showed high stability at pH 9-11. Mn2+ and Tween-80 improved its activity by 22% and 31%, respectively, while SDS, CMC and EDTA respectively inhibited its activity by 33%, 47% and 22%. Alkaline protease exhibited poor tolerance to n-butyl alcohol and ethanol, but showed resistance to H2O2. 29.8% of the original activity was still retained after 0.5 M H2O2 treatment for 3 min. The Km and Vmax values of this enzyme towards casein were 16.7 mg/ml and 14.7 µg/(min·ml), respectively. This study provides a basis for understanding enzymatic properties of Bacillus sp. ZJ1502 alkaline protease.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Endopeptidases/química , Peróxido de Hidrogênio/química , 1-Butanol/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Reatores Biológicos , Eletroforese em Gel de Poliacrilamida , Endopeptidases/isolamento & purificação , Endopeptidases/metabolismo , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Metais/química , Peso Molecular , Alimentos de Soja/microbiologia , Especificidade por Substrato , Tensoativos/química , Temperatura Ambiente
12.
Food Sci Technol Int ; 25(2): 141-149, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30286623

RESUMO

Lactic acid bacteria alone or with special adjunct probiotic strains are inevitable for the preparation of various specific functional foods. Moreover, because of their growth and metabolism, the final products are preserved for a certain time. Thus, growth dynamics of the lactic acid bacteria of the Fresco DVS 1010 culture ( Lactococcus lactis spp. lactis, Lactococcus lactis spp. cremoris, Streptococcus salivarius spp. thermophilus) during liquid-state fermentation of soya mashes and pH values within the process were analyzed in this study. Although milk is the most typical growth medium for the lactic acid bacteria, presumable viable counts of Fresco culture reached levels 109 CFU ml-1 after 8 h, representing 2-3 log increase in comparison to initial state (specific growth rates ranged from 1.06 to 1.64 h-1). After 21 days of storage period, the pH levels in the products were reduced to 4.50-4.70, representing a decrease of about 1.5-1.7 units. All prepared soybean products contained detectable amounts of raffinose-series oligosaccharides (0.25-0.68 g per 100 g) that were reduced in average by about 30.5% during period of 21 days.


Assuntos
Fermentação , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Lactobacillus plantarum/crescimento & desenvolvimento , Probióticos , Alimentos de Soja/microbiologia , Soja/microbiologia , Contagem de Colônia Microbiana , Alimento Funcional/microbiologia , Concentração de Íons de Hidrogênio , Ácido Láctico , Lactococcus lactis/crescimento & desenvolvimento , Modelos Biológicos , Oligossacarídeos/metabolismo , Rafinose/metabolismo , Streptococcus thermophilus/crescimento & desenvolvimento
13.
J Sci Food Agric ; 99(6): 3168-3175, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30537220

RESUMO

BACKGROUND: The salt-tolerant yeast strain Candida versatilis is usually added to high-salt, liquid-state soy sauce fermentation. The genome of C. versatilis was sequenced in our previous study but the reason for its high-osmolarity ability was not clear. RESULTS: The 9.7 Mbp genome of C. versatilis contained 4711 CDS. Candida versatilis was the closest to another yeast, Zygosaccharomyces rouxii, added to soy sauce fermentation. The protein sequence of the whole genome was divided into 4338 groups, accounting for 92.1% of all the predicted protein of C. versatilis using OrthoMCL. Mitogen-activated protein kinase (MAPK) signal pathways, including high osmolarity and cell integrity, were predicted and proved by investigating the expression changes of the key genes CvHOG1, CvGPD1, and CvFPS1 in a high osmotic environment and by testing the variations of intracellular glycerol and extracellular glycerol. CONCLUSION: Candida versatilis exhibited strong osmotolerance because it could synthesize intracellular glycerol and absorb glycerol from the environment cooperated with the shut down of glycerol efflux channel in membrane. © 2018 Society of Chemical Industry.


Assuntos
Candida/química , Candida/genética , Alimentos de Soja/microbiologia , Candida/metabolismo , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genoma Fúngico , Glicerol/metabolismo , Osmose , Alimentos de Soja/análise
14.
J Biosci Bioeng ; 127(2): 183-189, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30146188

RESUMO

Koji is a traditional fermentation culture medium, based on Aspergillus oryzae, which is commonly used in the manufacture process of Japanese fermented products such as soy sauce, miso, and sake, and promote enzymatic degradation. Koji is usually prepared by culturing a mold on cereals such as wheat flour, soybean, or rice, but that cultured on seaweeds has not been developed yet. This study prepared the koji by culturing A. oryzae on seaweed nori (dried piece of Pyropia yezoensis), and, then, characterized on this nori koji. The nori koji contained 0.85 µg N-acetylglucosamine, estimated as 6.1 µg mold cells, per gram dry matter and showed various kind of enzymatic activities in glycosidase, protease, and phosphatase as well as traditional soy sauce koji and rice koji. The suitability of these characteristics for degradation of nori was tested on nori sauce culture with and without the addition of the nori koji. After 167 days of culture, the fermentation tank with the nori koji showed over 74% recovery of supernatant while that without the nori koji had less than 57% recovery. The supernatant of culture mashes contained more than two times larger quantity of total nitrogen compounds in nori koji test group against control group. The present study prepared koji on seaweed nori for the first time and demonstrated its advantages to shorten the culture period and increase taste value in nori sauce manufacture. Development of seaweed koji enables a method to prepare cereal allergen free fermented sauces from seaweeds.


Assuntos
Aspergillus oryzae/citologia , Técnicas de Cocultura/métodos , Fermentação , Porphyra/citologia , Alga Marinha/metabolismo , Aspergillus oryzae/metabolismo , Reatores Biológicos/microbiologia , Oryza/microbiologia , Porphyra/metabolismo , Alga Marinha/química , Alga Marinha/citologia , Alimentos de Soja/microbiologia , Soja , Paladar
15.
Biotechnol Adv ; 37(1): 223-238, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30521852

RESUMO

For centuries, fermented soy foods have been dietary staples in Asia and, now, in response to consumer demand, they are available throughout the world. Fermentation bestows unique flavors, boosts nutritional values and increases or adds new functional properties. In this review, we describe the functional properties and underlying action mechanisms of soy-based fermented foods such as Natto, fermented soy milk, Tempeh and soy sauce. When possible, the contribution of specific bioactive components is highlighted. While numerous studies with in vitro and animal models have hinted at the functionality of fermented soy foods, ascribing health benefits requires well-designed, often complex human studies with analysis of diet, lifestyle, family and medical history combined with long-term follow-ups for each subject. In addition, the contribution of the microbiome to the bioactivities of fermented soy foods, possibly mediated through direct action or bioactive metabolites, needs to be studied. Potential synergy or other interactions among the microorganisms carrying out the fermentation and the host's microbial community may also contribute to food functionality, but the details still require elucidation. Finally, safety evaluation of fermented soy foods has been limited, but is essential in order to provide guidelines for consumption and confirm lack of toxicity.


Assuntos
/microbiologia , Leite de Soja/química , Soja/química , Fermentação , Humanos , Microrganismos Geneticamente Modificados/genética , Alimentos de Soja/microbiologia , Leite de Soja/metabolismo , Soja/genética , Soja/microbiologia
16.
PLoS One ; 13(12): e0208821, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30586377

RESUMO

Tetragenococcus halophilus is a halophilic lactic acid bacterium that exists in the traditional Japanese seasoning miso-a fermented soy paste. Considering the popularity of miso as a component of healthy diet, we attempted to evaluate the immunoregulatory functions of T. halophilus spices isolated from miso. We screened 56 strains that facilitated the upregulation of activation markers such as CD86 and CD69 on B cells and T cells in vitro. Of these, 7 strains (Nos. 1, 3, 13, 15, 19, 30, and 31) were found to preferentially induce the CD86 expression on B cells. Furthermore, DNA microarray analysis revealed that T. halophilus strain No. 1 significantly augmented the gene expressions of CD86, CD70, IL-10, INF-γ, and IL-22 in B cells. We confirmed these results at the protein level by flow cytometry. Mice feeding diet containing 1% T. halophilus No. 1 exhibited significantly greater IgA production in the serum. Furthermore, a diet containing 1% T. halophilus No. 1 augmented ovoalbumin (OVA)-specific IgG titer in mice upon OVA/alum immunization. Thus, we demonstrated that T. halophilus No. 1 is a strong immunomodulatory strain with potential as a probiotic.


Assuntos
Linfócitos B/microbiologia , Enterococcaceae/isolamento & purificação , Alimentos de Soja/microbiologia , Linfócitos T/microbiologia , Animais , Linfócitos B/metabolismo , Citocinas/metabolismo , Microbiologia de Alimentos , Regulação da Expressão Gênica , Camundongos , Linfócitos T/metabolismo
17.
J Nutr Sci Vitaminol (Tokyo) ; 64(5): 379-383, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30381629

RESUMO

The regional standard for tempeh established by the Codex Alimentarius defines the use of Rhizopus oligosporus, R. oryzae, and/or R. stolonifer as soybean tempeh starters. However, comparative studies on the functions of tempeh prepared with these Rhizopus species are scarce. In the present study, we examined the effects of dietary tempeh prepared with these three Rhizopus species using rats fed with a high-fat diet. Compared to the control diet, consumption of tempeh prepared with R. stolonifer significantly suppressed serum levels of aspartate transaminase, total bilirubin, and ammonium (indices of liver function). However, less or no suppression was observed with tempeh prepared with R. oligosporus or R. oryzae. Serum levels of triglyceride, total cholesterol, HDL cholesterol, and glucose were unaffected. Liver levels of free cholesterol, a parameter relating to liver injury, were significantly decreased by the three types of the tempeh examined; however, there was no difference in the free cholesterol levels among the tempeh groups. We conclude that the ingestion of tempeh prepared with R. stolonifer might have beneficial effects pertaining to the liver function in rats fed with high-fat diets.


Assuntos
Dieta Hiperlipídica , Manipulação de Alimentos , Fígado/metabolismo , Rhizopus , Alimentos de Soja/microbiologia , Soja/microbiologia , Compostos de Amônio/sangue , Animais , Aspartato Aminotransferases/sangue , Bilirrubina/sangue , Colesterol/metabolismo , Comportamento Alimentar , Fermentação , Tecnologia de Alimentos , Masculino , Ratos Sprague-Dawley , Rhizopus/classificação , Especificidade da Espécie
18.
Biomol Concepts ; 9(1): 131-142, 2018 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-30481150

RESUMO

Bacteriophages are ubiquitous and have been reported to have been found in many food products. Their presence is important as they have the ability to interact with their bacterial host in food matrices. Fermented soybean products, one of the most widely consumed ethnic foods among Asian people, are prepared naturally and include Japanese Natto, Indian Kinema, Korean Chongkukjang and Thai Thua Nao. This review highlights bacteriophages which have been isolated from fermented soybean products and also includes an overview of their diversity, occurrence as well as their significance.


Assuntos
Bacteriófagos/isolamento & purificação , Alimentos de Soja/virologia , Soja/virologia , Bacillus/isolamento & purificação , Bacillus/virologia , Fermentação , Qualidade dos Alimentos , Alimentos de Soja/microbiologia , Alimentos de Soja/normas , Soja/microbiologia
19.
Appl Microbiol Biotechnol ; 102(23): 10017-10026, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30284011

RESUMO

Okara (soybean residue), a by-product from soymilk and tofu production, has a green, grassy off odour as it contains a large amount of aldehydes. This work investigated the rate-limiting enzyme(s) in the formation of aldehydes in okara and the pathways leading to their bioconversion into fruity, pleasant-smelling esters by the yeast Lindnera saturnus. Lipase and hydroperoxide lyase were shown to be rate-limiting enzymes while endogenous soy lipoxygenase was also crucial for the production of aldehydes in okara. Subsequent fermentation of okara by L. saturnus increased the amount of esters by about 70 times to 165-277 µg/g dried okara. The generation of C7 esters followed our hypothesised pathway, while that for C6 esters was mainly affected by L. saturnus. This study presents a simple and inexpensive one-pot setup for the natural bio-production of esters from okara.


Assuntos
Ésteres/metabolismo , Proteínas de Plantas/química , Polissacarídeos/química , Saccharomycetales/metabolismo , Alimentos de Soja/microbiologia , Compostos Orgânicos Voláteis/metabolismo , Aldeído Liases/metabolismo , Catálise , Sistema Enzimático do Citocromo P-450/metabolismo , Fermentação , Manipulação de Alimentos , Microbiologia Industrial , Ácido Linoleico/análise , Lipase/metabolismo , Lipoxigenase/metabolismo , Ácido alfa-Linoleico/análise
20.
Food Microbiol ; 76: 196-203, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30166141

RESUMO

While the detrimental effect of bacteriophages on lactic acid bacterial fermentation is well documented, the importance of Bacillus subtilis phages in soybean-based fermented foods is not. In this study, we show for the first time that 100% of Korean soybean-based fermented foods (Doenjang, Gochujang, and Cheonggukjang) and 70% of raw materials (Meju and rice straw) were contaminated with B. subtilis-infecting phages (as high as 3.7 × 104 PFU g-1). Among 15 isolated B. subtilis-infecting phages, BSP18 was selected for further studies due to its specificity to and relatively broad host infectivity (34%) against B. subtilis. This Myoviridae family phage, BSP18 could infect all of the tested wild-type and commercially-used strains for soybean-based fermented food preparation. Furthermore, artificial contamination of as low as 102 PFU g-1 of BSP18 significantly inhibited B. subtilis growth during Cheonggukjang fermentation. Moreover, phage-treated samples contained considerably more degraded γ-PGA which could negatively affect the functional property of Cheonggukjang. We also present the data, strongly suggesting BSP18-encoded, not bacterial, γ-PGA hydrolase was responsible for γ-PGA degradation. In conclusion, B. subtilis phages are widespread in Korean soybean-based fermented foods and it should be of great concern as phages may hamper the bacterial growth during fermentation and yield poor quality products.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/virologia , Bacteriófagos/isolamento & purificação , Myoviridae/isolamento & purificação , Alimentos de Soja/virologia , Bacillus subtilis/metabolismo , Bacteriófagos/metabolismo , República Democrática Popular da Coreia , Fermentação , Microbiologia de Alimentos/métodos , Myoviridae/genética , Oryza/microbiologia , Oryza/virologia , Ácido Poliglutâmico/análogos & derivados , Ácido Poliglutâmico/análise , Prevalência , Alimentos de Soja/microbiologia
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