Tea plants grown under sunshade net and greenhouse are new methods for coping with high- temperature stress in later summer in middle and south China. Aroma is one of the most important flavors and qualities of tea. I...Tea plants grown under sunshade net and greenhouse are new methods for coping with high- temperature stress in later summer in middle and south China. Aroma is one of the most important flavors and qualities of tea. In this research the cultivar “Longjing-changye” (LJCY) was grown under sunshade net, greenhouse and open field as treatments to study the changes of aromatic substances by using Head Space Solid Phase-microextraction and Gas Chromatography-Mass Spectrometry (HS-SPME/GC-MS). The results showed that tea plants grown under sunshade net and greenhouse had higher content of aroma substances in autumn tea. Those growing conditions are good for improving the contents of the ester and geraniol with floral and fruity fragrance in autumn tea. Moreover, overshadowing in summer is helpful to improve fragrance of fresh tea leaves quality in autumn tea, particularly the 50% sunshade net.展开更多
依据专家感官审评结果将14个红茶样本按香气品质的优劣划分为优质红茶与缺陷红茶2组,基于快速气相电子鼻(fast gas chromatography-electronic-nose,GC-E-Nose)和气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)融合技术结...依据专家感官审评结果将14个红茶样本按香气品质的优劣划分为优质红茶与缺陷红茶2组,基于快速气相电子鼻(fast gas chromatography-electronic-nose,GC-E-Nose)和气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)融合技术结合多元统计分析对2组茶样进行判别分析,筛选影响两类茶样分类的关键差异组分。结果显示:GC-E-Nose(44维)和GC-MS(73维)相融合可以得到117维融合数据集,用其建立的正交偏最小二乘判别分析模型可以实现两类红茶的准确分类,其模型解释能力和预测能力(R_(Y)^(2)=0.976,Q^(2)=0.959)较单一的GC-E-Nose或GC-MS数据模型更优。基于变量投影重要性>1.6和P<0.05双变量原则,共筛选出二甲基硫醚(B3、B25)、β-紫罗酮(A59)、(3E)-4,8-二甲基壬-1,3,7-三烯(A20)、二氢猕猴桃内酯(A64)、芳樟醇(A17)、苯乙醇(A19)、δ-辛内酯(A41)和γ-壬内酯(A45)8个关键香气组分对分类起重要作用。研究结果表明,GC-E-Nose与GC-MS融合技术可以实现缺陷红茶和优质红茶的快速、准确分类,该方法可作为传统感官审评方法的补充,为红茶品质控制和质量提升提供技术支撑。展开更多
为揭示云南两个品种基于六堡茶工艺加工后的茶叶的香气成分,探讨较为合适制作六堡茶的茶树品种,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-...为揭示云南两个品种基于六堡茶工艺加工后的茶叶的香气成分,探讨较为合适制作六堡茶的茶树品种,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC/MS),结合相对香气活度值(Relative Odor Activity Value,ROAV)法分析云南两个品种茶叶渥堆发酵的挥发性成分。结果表明,共检测出152种挥发性成分,以醇类、酯类挥发性成分种类为主,以芳樟醇、月桂烯醇、壬醛、二氢猕猴桃内酯、亚麻酸甲酯和棕榈酸甲酯相对含量较高。ROAV贡献值分析结果显示:两个品种加工过程中主要香气贡献挥发性成分有19种,两个样品显著(P<0.05)贡献的香气化合物包括苯甲醇、癸醛、壬醛、α-紫罗酮、1-辛烯-3-醇、雪松醇、芳樟醇、反式-芳樟醇氧化物(呋喃型)。壬醛、癸醛、β-紫罗兰酮等3种挥发性有机化合物对云抗10号(Y6)陈香的形成具有较大贡献,α-雪松醇、长叶蒎烯、β-柏木烯、右旋萜二烯、α-紫罗酮等5种挥发性有机化合物对黑龙潭群体种(H6)陈香透参香的形成具有较大贡献。本研究从香气成分的角度明确了云抗10号、黑龙潭群体种均适合作为六堡茶原料,其中黑龙潭群体种在感官审评、关键香气成分种类和含量都高于云抗10号,因此黑龙潭群体种相较于云抗10号更适合做六堡茶。展开更多
文摘Tea plants grown under sunshade net and greenhouse are new methods for coping with high- temperature stress in later summer in middle and south China. Aroma is one of the most important flavors and qualities of tea. In this research the cultivar “Longjing-changye” (LJCY) was grown under sunshade net, greenhouse and open field as treatments to study the changes of aromatic substances by using Head Space Solid Phase-microextraction and Gas Chromatography-Mass Spectrometry (HS-SPME/GC-MS). The results showed that tea plants grown under sunshade net and greenhouse had higher content of aroma substances in autumn tea. Those growing conditions are good for improving the contents of the ester and geraniol with floral and fruity fragrance in autumn tea. Moreover, overshadowing in summer is helpful to improve fragrance of fresh tea leaves quality in autumn tea, particularly the 50% sunshade net.
文摘依据专家感官审评结果将14个红茶样本按香气品质的优劣划分为优质红茶与缺陷红茶2组,基于快速气相电子鼻(fast gas chromatography-electronic-nose,GC-E-Nose)和气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)融合技术结合多元统计分析对2组茶样进行判别分析,筛选影响两类茶样分类的关键差异组分。结果显示:GC-E-Nose(44维)和GC-MS(73维)相融合可以得到117维融合数据集,用其建立的正交偏最小二乘判别分析模型可以实现两类红茶的准确分类,其模型解释能力和预测能力(R_(Y)^(2)=0.976,Q^(2)=0.959)较单一的GC-E-Nose或GC-MS数据模型更优。基于变量投影重要性>1.6和P<0.05双变量原则,共筛选出二甲基硫醚(B3、B25)、β-紫罗酮(A59)、(3E)-4,8-二甲基壬-1,3,7-三烯(A20)、二氢猕猴桃内酯(A64)、芳樟醇(A17)、苯乙醇(A19)、δ-辛内酯(A41)和γ-壬内酯(A45)8个关键香气组分对分类起重要作用。研究结果表明,GC-E-Nose与GC-MS融合技术可以实现缺陷红茶和优质红茶的快速、准确分类,该方法可作为传统感官审评方法的补充,为红茶品质控制和质量提升提供技术支撑。
文摘为揭示云南两个品种基于六堡茶工艺加工后的茶叶的香气成分,探讨较为合适制作六堡茶的茶树品种,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC/MS),结合相对香气活度值(Relative Odor Activity Value,ROAV)法分析云南两个品种茶叶渥堆发酵的挥发性成分。结果表明,共检测出152种挥发性成分,以醇类、酯类挥发性成分种类为主,以芳樟醇、月桂烯醇、壬醛、二氢猕猴桃内酯、亚麻酸甲酯和棕榈酸甲酯相对含量较高。ROAV贡献值分析结果显示:两个品种加工过程中主要香气贡献挥发性成分有19种,两个样品显著(P<0.05)贡献的香气化合物包括苯甲醇、癸醛、壬醛、α-紫罗酮、1-辛烯-3-醇、雪松醇、芳樟醇、反式-芳樟醇氧化物(呋喃型)。壬醛、癸醛、β-紫罗兰酮等3种挥发性有机化合物对云抗10号(Y6)陈香的形成具有较大贡献,α-雪松醇、长叶蒎烯、β-柏木烯、右旋萜二烯、α-紫罗酮等5种挥发性有机化合物对黑龙潭群体种(H6)陈香透参香的形成具有较大贡献。本研究从香气成分的角度明确了云抗10号、黑龙潭群体种均适合作为六堡茶原料,其中黑龙潭群体种在感官审评、关键香气成分种类和含量都高于云抗10号,因此黑龙潭群体种相较于云抗10号更适合做六堡茶。
文摘为探究蒸汽爆破(汽爆)辅助加工制成杜仲叶茶的挥发性成分差异和主要呈香特征,以杜仲‘华仲8号’嫩叶和成熟叶为对象,采用汽爆技术对杜仲叶进行处理,基于电子鼻和顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction combined with gas chromatography-mass spectrometry,HS-SPME-GC-MS)联用法解析汽爆对两种杜仲茶香气特征的影响。主成分分析和线性判别分析对电子鼻数据模型拟合度高,杜仲嫩叶和成熟叶茶汽爆前后香气特征均存在显著差异。HS-SPME-GC-MS检测共鉴定出177种挥发性成分,通过正交偏最小二乘判别分析(变量重要性投影值≥1)以及Kruskal-WallisH检验(P<0.05)进一步筛选出24种香气物质,发现汽爆前嫩叶茶关键香气物质为二氢猕猴桃内酯。汽爆后嫩叶茶关键呈香物质在此基础上增加了壬醛、苯甲醛和苯乙醛,呈现柑橘香、花香、焦糖香、苦杏仁味、坚果香、玫瑰香和巧克力香。汽爆前成熟叶茶无关键香气物质,汽爆后成熟叶茶关键香气物质为二氢猕猴桃内酯和壬醛,呈现甜桃香、木香、柑橘香、花香和焦糖香。研究结果可为开发杜仲叶茶饮品提供参考依据。
