摘要
为探明不同烘焙处理条件对岩茶品质与化学成分的影响,以肉桂品种(Camellia sinensis(L.)O.Kuntze cv.Rougui)岩茶毛茶为研究对象,设置不同烘焙温度(低火:100℃、中火:120℃、高火:140℃)与烘焙时间(2、4、6、8、10 h),采用基于超高效液相色谱-四极杆-静电轨道阱质谱(ultra-high performance liquid chromatography-quadrupole orbitrap mass spectrometry,UPLC-Q-Exactive/MS)的代谢组学方法对其非挥发性化学成分进行系统研究并结合感官审评对其品质进行鉴定。本研究共鉴定出144种化合物,包括生物碱类、儿茶素类、二聚儿茶素类、氨基酸类、酚酸类、N-乙基-2-吡咯烷酮取代的儿茶素(N-ethyl-2-pyrrolidinone-substituted flavan-3-ols,EPSF)类、香气糖苷类、黄酮糖苷类及脂质类等11类化合物。偏最小二乘法判别分析和热图分析结果表明,不同烘焙处理岩茶化学成分存在较大差异,共得到84种具有组间显著性差异的化合物(P<0.05),其中绝大部分为氨基酸类物质,以及大部分儿茶素类、二聚儿茶素类(茶黄素、聚酯型儿茶素)、生物碱类(5’-甲硫腺苷、磷酸腺苷等)、酚酸类(异绿原酸、小木麻黄素、茶没食子素等)及大部分黄酮糖苷类等化合物在温度达到120℃(中火)后随着焙火时间的延长含量逐渐下降。而大部分脂质类(甘油单酯(18:3)、溶血磷脂酰胆碱(18:3)、棕榈酸等)、小部分黄酮糖苷类化合物(杨梅素、山柰苷、槲皮素等)、部分有机酸类物质(焦谷氨酸、5-羟甲基-2-糠醛)等呈相反的变化趋势;绝大部分EPSF类化合物含量随着焙火温度升高和时间的延长而呈线性增加,但在温度达到140℃(高火)后随着烘焙时间的延长含量逐渐降低。感官审评鉴定表明,低温长时(100℃、8~10 h)或中温短时(120℃、2~4 h)烘焙有利于肉桂岩茶品质的提升。本研究采用UPLC-Q-Exactive/MS方法较为系统全面地阐明了肉桂岩茶在不同烘焙条件下样品化学物质的差异,为武夷岩茶品质研究及焙火工艺提供理论依据。
In order to investigate the influence of different roasting degrees on the quality and chemical composition of Rougui rock tea(Camellia sinensis(L.)O.Kuntze cv.Rougui),the non-volatile chemical compositions of tea samples processed at different roasting temperatures(low fire:100℃,medium fire:120℃,high fire:140℃)and for different time periods(2,4,6,8 and 10 h)were systematically investigated by metabolomics based on ultra-high performance liquid chromatography-quadrupole orbitrap mass spectrometry(UPLC-Q-Exactive/MS),and their quality was evaluated by sensory evaluation.A total of 144 compounds were structurally identified,belonging to 11 chemical classes including catechins,dimeric catechins,flavonoid glycosides(flavonol-O-glycosides and flavone-C-glycosides),N-ethyl-2-pyrrolidinone-substituted flavan-3-ols(EPSFs),amino acids,phenolic acids,organic acids,alkaloids,and lipids.Partial least squares discriminant(PLSD)analysis and heatmap analysis showed distinct differences in chemical components among rock tea samples with different baking treatments.A total of 84 compounds that significantly differed among treatment groups were identified(P<0.05).The contents of most amino acids,epicatechins,dimeric catechins(theaflavins and theasinensins),alkaloids(5’-methionosine and adenosine phosphate),phenolic acids(isochlorogenic acid,strictinin and theogallin),and flavonoid glycosides were gradually decreased with roasting time at 120℃,while most lipids(MG(18:3),LysoPC(18:3),and palmitic acid),some flavonol aglycones(myricetin,kaempferol,and quercetin),and some organic acids(pyroglutamic acid and 5-hydroxymethyl-2-furfural)showed the opposite trend.The contents of most EPSF compounds were increased linearly with roasting temperature and time,but it was gradually decreased with baking time at 140℃.Sensory evaluation showed that low-temperature long-time(8-10 h at 100℃)and medium-temperature short-time(2-4 h at 120℃)were beneficial for the quality improvement of rock tea.This study provides a theoretical basis for the quality improvement of Wuyi rock tea.
作者
钟秋生
彭佳堃
戴伟东
林智
吕海鹏
陈泉宾
李鑫磊
陈常颂
ZHONG Qiusheng;PENG Jiakun;DAI Weidong;LIN Zhi;LÜHaipeng;CHEN Quanbin;LI Xinlei;CHEN Changsong(Tea Research Institute,Fujian Academy of Agricultural Sciences,Fuzhou 350012,China;Tea Research Institute,Chinese Academy of Agricultural Sciences,Hangzhou 310008,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2023年第20期268-282,共15页
Food Science
基金
福建省公益科研院所专项(2021R1029006,2021R1029004)
财政部和农业部:国家茶叶产业技术体系项目(CARS-19)
农业高质量发展超越“5511”协同创新工程项目(XTCXGC2021004)
国家自然科学基金面上项目(32172630)
福建省农业科学院科技创新团队项目(CXTD2021006-1)。
关键词
武夷岩茶
烘焙
化学成分
超高效液相色谱-四极杆-静电轨道阱质谱联用
代谢组学
感官评价
Wuyi rock tea
roasting
chemical composition
ultra-high performance liquid chromatography-quadrupole orbitrap mass spectrometry
metabolomics
sensory evaluation