The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of th...The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of three Holstein cows.Based onhigher activity of cellulose or nitrogenase,three CB types[CB-2(KT725624),CB-5(KT725623)and CB-6(KT725622)]and one NFB type[NFB-3(KT735054)]were screened out,respectively.Two parts were included in this study.The first part explored the optimal mixed ratio of CB to NFB through inoculating filter paper medium with the bacteria of 2×10^5 cfu·mL^-1.According to CMCase and FPase activities in the medium,the ratio of 4 to 1 was proven to be more effective.In the second part,rumen fermentation in vitro was conducted at 4:1 of CB to NFB,aiming at studying the effects of mixed bacteria.Six groups were classified,namely,control group(no bacteria),Group 1(CB-2+NFB-3),Group 2(CB-5+NFB-3),Group 3(CB-6+NFB-3),Group 4(NFB-3)and Group 5(CB-6).All the experimental groups had the same amount of bacteria(4×10^6 cfu·mL^-1)in the fermentation liquid.Samples were collected at 2,4,8,12 and 24 h of incubation.Compared with the groups with CB or NFB alone,gas production,dry matter degradability and bacterial protein expressions in the mixed groups increased.However,NH3-N concentration decreased and p H was stable.Meanwhile,related values among three mixed groups were significantly different;values in Group 2 were the best.展开更多
为开发新型高品质的蜂蜜茶酒,利用酿酒酵母和非酿酒酵母混菌发酵制备蜂蜜茶酒,采用电子鼻技术结合顶空固相微萃取-气相色谱-质谱(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC-MS),并...为开发新型高品质的蜂蜜茶酒,利用酿酒酵母和非酿酒酵母混菌发酵制备蜂蜜茶酒,采用电子鼻技术结合顶空固相微萃取-气相色谱-质谱(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC-MS),并对发酵蜂蜜茶酒的基本理化、有机酸和多酚含量进行检测,以酿酒酵母单菌发酵(SF)和非酿酒酵母单菌发酵(HF)产品作为对比分析,综合评价混菌发酵(MF)对蜂蜜茶酒品质和风味的影响。结果表明:相较于SF和HF,MF提高了蜂蜜茶酒总酚和总黄酮含量。发酵后样品的有机酸含量上升,多酚含量下降。HF电子鼻传感器响应值低,且MF大部分传感器响应值大于SF。HS-SPME-GC-MS共鉴定出75种香气成分,混菌发酵使蜂蜜茶酒中的挥发性化合物种类和含量显著增加(P<0.05)。PLS-DA分析共筛选出10种差异化合物(VIP>1),其中有6种为酯类风味物质。OAV>1的关键香气成分共有12种,相较于HF和SF,对MF香气贡献率较高的为具有花香的苯乙醇、蜂蜜甜香的乙酸苯乙酯、水果香气的甲酸戊酯和醋酸正丙酯等。综上,混菌发酵蜂蜜茶酒相较于单菌发酵更具优势,总体风味更丰富浓郁。本文为非酿酒酵母在酒类中的应用及茶叶副产物深加工利用提供了理论依据。展开更多
基金Supported by China Agriculture Research System(CARS-37)Northeast Agricultural University Innovation Funding for Postgraduate(yjscx14007)。
文摘The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of three Holstein cows.Based onhigher activity of cellulose or nitrogenase,three CB types[CB-2(KT725624),CB-5(KT725623)and CB-6(KT725622)]and one NFB type[NFB-3(KT735054)]were screened out,respectively.Two parts were included in this study.The first part explored the optimal mixed ratio of CB to NFB through inoculating filter paper medium with the bacteria of 2×10^5 cfu·mL^-1.According to CMCase and FPase activities in the medium,the ratio of 4 to 1 was proven to be more effective.In the second part,rumen fermentation in vitro was conducted at 4:1 of CB to NFB,aiming at studying the effects of mixed bacteria.Six groups were classified,namely,control group(no bacteria),Group 1(CB-2+NFB-3),Group 2(CB-5+NFB-3),Group 3(CB-6+NFB-3),Group 4(NFB-3)and Group 5(CB-6).All the experimental groups had the same amount of bacteria(4×10^6 cfu·mL^-1)in the fermentation liquid.Samples were collected at 2,4,8,12 and 24 h of incubation.Compared with the groups with CB or NFB alone,gas production,dry matter degradability and bacterial protein expressions in the mixed groups increased.However,NH3-N concentration decreased and p H was stable.Meanwhile,related values among three mixed groups were significantly different;values in Group 2 were the best.
文摘为开发新型高品质的蜂蜜茶酒,利用酿酒酵母和非酿酒酵母混菌发酵制备蜂蜜茶酒,采用电子鼻技术结合顶空固相微萃取-气相色谱-质谱(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC-MS),并对发酵蜂蜜茶酒的基本理化、有机酸和多酚含量进行检测,以酿酒酵母单菌发酵(SF)和非酿酒酵母单菌发酵(HF)产品作为对比分析,综合评价混菌发酵(MF)对蜂蜜茶酒品质和风味的影响。结果表明:相较于SF和HF,MF提高了蜂蜜茶酒总酚和总黄酮含量。发酵后样品的有机酸含量上升,多酚含量下降。HF电子鼻传感器响应值低,且MF大部分传感器响应值大于SF。HS-SPME-GC-MS共鉴定出75种香气成分,混菌发酵使蜂蜜茶酒中的挥发性化合物种类和含量显著增加(P<0.05)。PLS-DA分析共筛选出10种差异化合物(VIP>1),其中有6种为酯类风味物质。OAV>1的关键香气成分共有12种,相较于HF和SF,对MF香气贡献率较高的为具有花香的苯乙醇、蜂蜜甜香的乙酸苯乙酯、水果香气的甲酸戊酯和醋酸正丙酯等。综上,混菌发酵蜂蜜茶酒相较于单菌发酵更具优势,总体风味更丰富浓郁。本文为非酿酒酵母在酒类中的应用及茶叶副产物深加工利用提供了理论依据。
