米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优...米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优势细菌属,东南组的优势细菌属为红球菌属(Rhodococcus)(14.6%),东南组中5个组的菌群结构在属水平上类似,表明米酒曲的菌群结构与地域环境有一定联系。根霉属(Rhizopus)在所有米酒曲样品中占绝对优势(80.98%~99.22%)。米酒曲中细菌菌落总数最高的为湖北省孝感地区的酒曲(8.21 lg CFU/g),霉菌孢子数最高的为广东佛山的酒曲(9.61 lg个/g),酵母菌菌落总数最高的为安徽省阜阳市地区的酒曲(10.02 lg CFU/g)。同时,筛选获得酒曲中优势菌株功能菌4株,将4株功能菌株接种强化米酒曲,结果表明同时接种商业酒曲和功能菌株(SG组)的酒曲糖化酶、蛋白酶活力分别提高至1583.4 U和776.13 U/g,SG组的酯类物质种类最多达到17种,并且SG组的醇类、酯类和烷烃类物质的含量均显著提高,分别达到了1021.94、1190.82、535.80μg/100 g,表明功能菌在米酒及米酒曲中应用潜力巨大。展开更多
By the addition of rice wine koji, enhancement of the reactivity was observed for the baker＇s yeast reduction of β-keto esters into （S）-β-hydroxy esters with high enantiomeric purity （73-98%）.
In this study, effect of rice added to meju dough was evaluated based on the variation of nutritional ingredients and bacterial community diversity in finished doenjang. The ratio of rice added to meju dough (cooked a...In this study, effect of rice added to meju dough was evaluated based on the variation of nutritional ingredients and bacterial community diversity in finished doenjang. The ratio of rice added to meju dough (cooked and crushed soybean before fermentation) was 0, 0.2, and 0.4 based on dry weight. Free amino acids, minerals, polyphenol, and total phenolic compounds relatively decreased by addition of rice. However, 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging and ferric ion reduction activity was not influenced. Organic acids, which are fermentation metabolites, significantly increased in proportion to percentage balance of rice. Seven and four volatile compounds (VCs) were detected in doenjang prepared without and with rice, respectively, and contents of VCs were significantly lower in the rice-supplemented doenjang. Bacterial community diversity was significantly increased by addition of rice to meju dough. Rice alters chemical composition, fermentation products, and bacterial diversity, but does not downgrade the nature of doenjang.展开更多
The effect of thermally processed rice koji extracts on survival of yeast Saccharomyces cerevisiae was examined in comparison with non-heated koji extract. In chronological life span (CLS) tests on high-sugar fermenta...The effect of thermally processed rice koji extracts on survival of yeast Saccharomyces cerevisiae was examined in comparison with non-heated koji extract. In chronological life span (CLS) tests on high-sugar fermentation, the survivals of the yeast cells grown with heated koji extracts were higher than non-heated koji extract. Heat treatment of the extracts by autoclaving led to a loss in most of amino acids due to the Maillard reaction, although histidine contents slightly increased. In glucose-arginine mixtures, arginine was partly converted to histidine by autoclaving and the addition of histidine prolonged the CLS of yeast cells. The yeast cells grown with the non-heated extracts were more resistant to oxidative stress whereas the antioxidant activities were lower than those of the heated extracts. The yeast cells grown with the heated extracts were more tolerant to ethanol and had a higher reduction capacity in the late stationary phase when the cells were incubated in the presence of ethanol. Maillard reaction products elevated the levels of reactive oxygen species to yeast cells grown under ethanol stress in the late stationary phase. These results suggest that thermally processed koji extracts can act as a protectant against ethanol stress during the late stationary phase of yeast growth and extend the CLS due to the increase of histidine contents by autoclaving.展开更多
文摘米酒曲中微生物种类多样,微生物之间的相互作用影响着米酒的风味与品质。该研究基于高通量测序技术分析了我国南方地区米酒曲中微生物菌群多样性,研究结果表明,雷尔氏菌属(Ralstonia)和魏斯氏菌属(Weissella)为东南组和中部组的共同优势细菌属,东南组的优势细菌属为红球菌属(Rhodococcus)(14.6%),东南组中5个组的菌群结构在属水平上类似,表明米酒曲的菌群结构与地域环境有一定联系。根霉属(Rhizopus)在所有米酒曲样品中占绝对优势(80.98%~99.22%)。米酒曲中细菌菌落总数最高的为湖北省孝感地区的酒曲(8.21 lg CFU/g),霉菌孢子数最高的为广东佛山的酒曲(9.61 lg个/g),酵母菌菌落总数最高的为安徽省阜阳市地区的酒曲(10.02 lg CFU/g)。同时,筛选获得酒曲中优势菌株功能菌4株,将4株功能菌株接种强化米酒曲,结果表明同时接种商业酒曲和功能菌株(SG组)的酒曲糖化酶、蛋白酶活力分别提高至1583.4 U和776.13 U/g,SG组的酯类物质种类最多达到17种,并且SG组的醇类、酯类和烷烃类物质的含量均显著提高,分别达到了1021.94、1190.82、535.80μg/100 g,表明功能菌在米酒及米酒曲中应用潜力巨大。
文摘By the addition of rice wine koji, enhancement of the reactivity was observed for the baker＇s yeast reduction of β-keto esters into （S）-β-hydroxy esters with high enantiomeric purity （73-98%）.
文摘In this study, effect of rice added to meju dough was evaluated based on the variation of nutritional ingredients and bacterial community diversity in finished doenjang. The ratio of rice added to meju dough (cooked and crushed soybean before fermentation) was 0, 0.2, and 0.4 based on dry weight. Free amino acids, minerals, polyphenol, and total phenolic compounds relatively decreased by addition of rice. However, 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging and ferric ion reduction activity was not influenced. Organic acids, which are fermentation metabolites, significantly increased in proportion to percentage balance of rice. Seven and four volatile compounds (VCs) were detected in doenjang prepared without and with rice, respectively, and contents of VCs were significantly lower in the rice-supplemented doenjang. Bacterial community diversity was significantly increased by addition of rice to meju dough. Rice alters chemical composition, fermentation products, and bacterial diversity, but does not downgrade the nature of doenjang.
文摘The effect of thermally processed rice koji extracts on survival of yeast Saccharomyces cerevisiae was examined in comparison with non-heated koji extract. In chronological life span (CLS) tests on high-sugar fermentation, the survivals of the yeast cells grown with heated koji extracts were higher than non-heated koji extract. Heat treatment of the extracts by autoclaving led to a loss in most of amino acids due to the Maillard reaction, although histidine contents slightly increased. In glucose-arginine mixtures, arginine was partly converted to histidine by autoclaving and the addition of histidine prolonged the CLS of yeast cells. The yeast cells grown with the non-heated extracts were more resistant to oxidative stress whereas the antioxidant activities were lower than those of the heated extracts. The yeast cells grown with the heated extracts were more tolerant to ethanol and had a higher reduction capacity in the late stationary phase when the cells were incubated in the presence of ethanol. Maillard reaction products elevated the levels of reactive oxygen species to yeast cells grown under ethanol stress in the late stationary phase. These results suggest that thermally processed koji extracts can act as a protectant against ethanol stress during the late stationary phase of yeast growth and extend the CLS due to the increase of histidine contents by autoclaving.
