Given that fermentation time has significant impact on quality and flavor of soy sauce,a global understanding of the metabolic mechanism as fermentation time prolonged is essential for producing satisfactory and consi...Given that fermentation time has significant impact on quality and flavor of soy sauce,a global understanding of the metabolic mechanism as fermentation time prolonged is essential for producing satisfactory and consistent quality of traditional soy sauce.Herein,the metabolic compounds changes of soy sauce associated with fermentation time up to 10 years were comprehensively investigated by using Chinese traditional fermented soy sauce(CTFSS)as a demonstration.Results showed that formaldehyde nitrogen,total soluble nitrogen(TSN),non-salt soluble solids,amino acids,free 5’-nucleotides and volatile compounds in CTFSS changed obviously during fermentation.Specifically,glutamic acid and aspartic acid were prominent in CTFSS.Continuous decrease in content of hypoxanthine(Hx)was found from 1 M(1-month soy sauce)to7 M(7-months soy sauce).Furthermore,a significant opposite tendency for changes between some volatile compounds and amino acids was indicated that there was a transformation between these two components.Therefore,a better understanding to the influence of fermentation time on soy sauce had been proposed.As the formation and conversion of amino acids and sugars might be mainly responsible for flavor formation in CTFSS,the ratio of these two reactions rate led the metabolism to be divided into three steps,degradation,conversion and balance.展开更多
The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spe...The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spectroscopy combined with standard normal variate-partial least squares-discriminant analysis (SNV-PLS-DA) was used to establish the discriminant analysis models for adulterated and brewed soy sauces. Chubang soy sauce was selected as an identification brand (negative, 70). The adulteration samples (positive, 72) were prepared by mixing Chubang soy sauce and blended soy sauce with different adulteration rates. Among them, the “blended soy sauce” sample was concocted of salt water (NaCl), monosodium glutamate (C<sub>5</sub>H<sub>10</sub>NNaO<sub>5</sub>) and caramel color (C<sub>6</sub>H<sub>8</sub>O<sub>3</sub>). The rigorous calibration-prediction-validation sample design was adopted. For the case of 1 mm, five waveband models (visible, short-NIR, long-NIR, whole NIR and whole scanning regions) were established respectively;in the case of 10 mm, three waveband models (visible, short-NIR and visible-short-NIR regions) for unsaturated absorption were also established respectively. In independent validation, the models of all wavebands in the cases of 1 mm and 10 mm have achieved good discrimination effects. For the case of 1 mm, the visible model achieved the optimal validation effect, the validation recognition-accuracy rate (RAR<sub>V</sub>) was 99.6%;while in the case of 10 mm, both the visible and visible-short-NIR models achieved the optimal validation effect (RAR<sub>V</sub> = 100%). The detection method does not require reagents and is fast and simple, which is easy to promote the application. The results can provide valuable reference for designing small dedicated spectrometers with different measurement modals and different spectral regions.展开更多
A Gram-positive, non-spore, round ended, straight rod Lactic acid bacteria were screened. The strain was screened out from the traditional pickle jar in Yutang soy sauce garden of Jining. In order to degrade the nitra...A Gram-positive, non-spore, round ended, straight rod Lactic acid bacteria were screened. The strain was screened out from the traditional pickle jar in Yutang soy sauce garden of Jining. In order to degrade the nitrate content in the fermentation process of traditional pickles and improve the quality of pickles, it is necessary to screen out nitrite degrading strains from pickles, and preliminarily locate nitrite reductase, and find out the most suitable pH, tempe<span style="font-family:;" "="">r<span>ature and culture time to degrade nitrite. <i>Lactobacillus</i><span> <i>plantarum</i></span> was screened by MRS medium in advance. After 48 hours of culture in a shaking table with <i>Bacillus</i><span> <i>subtilis</i></span>, the cell components were separated by centrifugation, wall breaking and other operations. After 20 hours at 30<span style="white-space:normal;">°</span>C, the content of nitrite in each component was determined by the naphthalene ethylenediamine hydrochloride method (NIR). The culture conditions were as follows: inoculation amount 3%, 6%, 9%, 12%, 15%;salinity 2%, 4%, 6%, 8%, 10%;temperature 15°C, 20<span style="white-space:normal;">°</span>C, 25<span style="white-space:normal;">°</span>C, 30<span style="white-space:normal;">°</span>C, 35<span style="white-space:normal;">°</span>C for 20 h. The results showed that the best degradation effect of nitrite was obtained under the conditions of 9% inoculum, salinity 5% and 30<span style="white-space:normal;">°</span>C. Under the conditions of 9% inoculum, 5% salinity and 30<span style="white-space:normal;">°</span>C for 5 h, 10 h, 20 h, 48 h, 66 h and 78 h, the results showed that the degradation amount gradually increased with the extension of time, and gradually maintained a stable state.<span> <i>Lactobacillus</i> <i>plantarum</i></span> JBA-3 is a new type of lactic acid bacteria which can degrade nitrite and produce nitrite reducta</span>se.</span>展开更多
基金financially supported by the National Key Research and Development Program of China(2016YFD0401501)Shanghai Pujiang Program(18PJ1432600)。
文摘Given that fermentation time has significant impact on quality and flavor of soy sauce,a global understanding of the metabolic mechanism as fermentation time prolonged is essential for producing satisfactory and consistent quality of traditional soy sauce.Herein,the metabolic compounds changes of soy sauce associated with fermentation time up to 10 years were comprehensively investigated by using Chinese traditional fermented soy sauce(CTFSS)as a demonstration.Results showed that formaldehyde nitrogen,total soluble nitrogen(TSN),non-salt soluble solids,amino acids,free 5’-nucleotides and volatile compounds in CTFSS changed obviously during fermentation.Specifically,glutamic acid and aspartic acid were prominent in CTFSS.Continuous decrease in content of hypoxanthine(Hx)was found from 1 M(1-month soy sauce)to7 M(7-months soy sauce).Furthermore,a significant opposite tendency for changes between some volatile compounds and amino acids was indicated that there was a transformation between these two components.Therefore,a better understanding to the influence of fermentation time on soy sauce had been proposed.As the formation and conversion of amino acids and sugars might be mainly responsible for flavor formation in CTFSS,the ratio of these two reactions rate led the metabolism to be divided into three steps,degradation,conversion and balance.
文摘The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spectroscopy combined with standard normal variate-partial least squares-discriminant analysis (SNV-PLS-DA) was used to establish the discriminant analysis models for adulterated and brewed soy sauces. Chubang soy sauce was selected as an identification brand (negative, 70). The adulteration samples (positive, 72) were prepared by mixing Chubang soy sauce and blended soy sauce with different adulteration rates. Among them, the “blended soy sauce” sample was concocted of salt water (NaCl), monosodium glutamate (C<sub>5</sub>H<sub>10</sub>NNaO<sub>5</sub>) and caramel color (C<sub>6</sub>H<sub>8</sub>O<sub>3</sub>). The rigorous calibration-prediction-validation sample design was adopted. For the case of 1 mm, five waveband models (visible, short-NIR, long-NIR, whole NIR and whole scanning regions) were established respectively;in the case of 10 mm, three waveband models (visible, short-NIR and visible-short-NIR regions) for unsaturated absorption were also established respectively. In independent validation, the models of all wavebands in the cases of 1 mm and 10 mm have achieved good discrimination effects. For the case of 1 mm, the visible model achieved the optimal validation effect, the validation recognition-accuracy rate (RAR<sub>V</sub>) was 99.6%;while in the case of 10 mm, both the visible and visible-short-NIR models achieved the optimal validation effect (RAR<sub>V</sub> = 100%). The detection method does not require reagents and is fast and simple, which is easy to promote the application. The results can provide valuable reference for designing small dedicated spectrometers with different measurement modals and different spectral regions.
文摘A Gram-positive, non-spore, round ended, straight rod Lactic acid bacteria were screened. The strain was screened out from the traditional pickle jar in Yutang soy sauce garden of Jining. In order to degrade the nitrate content in the fermentation process of traditional pickles and improve the quality of pickles, it is necessary to screen out nitrite degrading strains from pickles, and preliminarily locate nitrite reductase, and find out the most suitable pH, tempe<span style="font-family:;" "="">r<span>ature and culture time to degrade nitrite. <i>Lactobacillus</i><span> <i>plantarum</i></span> was screened by MRS medium in advance. After 48 hours of culture in a shaking table with <i>Bacillus</i><span> <i>subtilis</i></span>, the cell components were separated by centrifugation, wall breaking and other operations. After 20 hours at 30<span style="white-space:normal;">°</span>C, the content of nitrite in each component was determined by the naphthalene ethylenediamine hydrochloride method (NIR). The culture conditions were as follows: inoculation amount 3%, 6%, 9%, 12%, 15%;salinity 2%, 4%, 6%, 8%, 10%;temperature 15°C, 20<span style="white-space:normal;">°</span>C, 25<span style="white-space:normal;">°</span>C, 30<span style="white-space:normal;">°</span>C, 35<span style="white-space:normal;">°</span>C for 20 h. The results showed that the best degradation effect of nitrite was obtained under the conditions of 9% inoculum, salinity 5% and 30<span style="white-space:normal;">°</span>C. Under the conditions of 9% inoculum, 5% salinity and 30<span style="white-space:normal;">°</span>C for 5 h, 10 h, 20 h, 48 h, 66 h and 78 h, the results showed that the degradation amount gradually increased with the extension of time, and gradually maintained a stable state.<span> <i>Lactobacillus</i> <i>plantarum</i></span> JBA-3 is a new type of lactic acid bacteria which can degrade nitrite and produce nitrite reducta</span>se.</span>
