香榧种子生长发育过程中假种皮挥发油的变化

Changes of Volatile Oil Composition in Aril during the Growth and Development of Torreya grandis‘Merrillii’Seeds

【目的】探究香榧假种皮不同制备方式与分析方法对挥发油成分含量测定的影响,揭示香榧种子生长发育过程中假种皮挥发油成分的动态变化规律,为香榧假种皮的利用提供参考。【方法】结合气相色谱-质谱联用(GC-MS)技术,优化水蒸气蒸馏法(SD)和顶空固相微萃取法(HS-SPME)样品制备条件,选择适合的方法测定香榧种子生长发育过程中假种皮挥发性油成分与含量。【结果】1)基于GC-MS的分析结果,从成分种类及含量上来看,SD更适合香榧假种皮挥发油分析样品的制备。2)用SD-GC-MS分析,检测出假种皮挥发油成分有47种,包含萜烯类21种(柠檬烯、α-蒎烯、δ-杜松烯等)、萜醇类15种(芳樟醇、冰片、榄香醇等)、萜烯酯类3种(乙酸冰片酯、乙酸松油酯、乙酸香叶酯)、其他化合物8种(胡椒酮、抗氧剂264、棕榈酸等)。3)种子生长发育过程中,假种皮中的挥发性成分呈一定的变化规律,其中莰烯、β-蒎烯、萜品油烯等含量5—9月均呈上升趋势;部分成分5—8月上升到最大值后开始下降,如α-蒎烯、桧烯、月桂烯等;5—6月和8—9月单萜类和倍半萜类成分呈明显的负相关趋势,而6—7月由于假种皮处于生长时期,单萜类和倍半萜类组分均呈增加趋势。主成分分析发现,假种皮挥发油成分在5月和6月、7月和8月比较相似。【结论】香榧假种皮挥发油SD提取条件为料液比为1∶10、浸泡时间为1 h、提取时间为4 h;通过SD-GC-MS检测出47种化合物,共13483.14μg·g^(-1),主要成分为柠檬烯、α-蒎烯等萜烯类化合物;不同种实生长发育期的香榧假种皮中挥发性组分差异较大,化合物种类从5月份的35种增加到了9月份的47种,倍半萜类和含氧衍生物积累增多,挥发油成分的总含量从5—9月份先升后降;5—6月、7—8月的假种皮挥发油成分组成及含量比较接近,而9月份与其他4个月份差异较大。

【Objective】This study aims to explore the influence of different preparation and analysis methods on the determination of volatile oil composition and the contents,and reveal the dynamic changes of the contents in the Torreya grandis‘Merrillii’aril during the seed growth and development,as so to provide the rationale for the utilization of the aril.【Method】Steam distillation(SD)and headspace solid phase microextraction(HS-SPME)techniques were used and optimized for the sample preparation The gas chromatography-mass spectrometry(GC-MS)was used to determine the volatile components and the contents in the aril during the growth and development of T.grandis seeds.【Result】1)Based on GC-MS analysis,SD was more suitable for the sample preparation of volatile oil from T.grandis seeds in terms of the component and content.2)The SD-GC-MS analysis showed that there were 47 volatile oil components in the aril,including 21 terpenes(limonene,α-pinene,δ-juniene,etc.),15 terpene alcohols(linalool,borneol,elemol,etc.),three terpene esters(bornyl acetate,pine oil acetate,and geranyl acetate),and eight other compounds(piperone,antioxidant 264,palmitic acid,etc.).3)The volatile components in the aril during seed growth and development showed certain regular changes.Among them the content of camphene,β-pinene,and terpinolene increased from May to September;the content of such ingredients asα-pinene,cypressene,and myrcene gradually rose to the peak value from May to August and then declined.The monoterpenoids and sesquiterpenoids showed an obvious negative correlation during May to June and from August to September,while the monoterpenoids and sesquiterpenoids showed an increasing trend from June to July because the aril was growing.PCA suggested that the volatile oil components of aril in May were similar to those in June【Conclusion】The extraction condition for T.grandis‘Merrillii’aril is the ratio of material to liquid set as 1∶10,and soak time as 1 hour,extraction time as 4 hours.Through the SD-GC-MS detection,47 compounds were identified,with a total of 13483.14μg·g^(-1).The main ingredients include limonene andα-pinene compounds.The volatile components in the aril of T.grandis‘Merrillii’are significantly different at different seed growth and development stages.The number of compounds increased from 35 in May to 47 in September.Sesquiterpenoids and oxygenic derivatives increased,and the total content of essential oil increased first and then decreased from May to September.The composition and content of essential oil in the aril were similar from May to June and July to August,but they were significantly different from those in September.