香蕉果实MAPs测定方法的建立及其含量变化规律研究

Establishment of a determination method of MAPs in banana fruit and study on its content variation rule

【目的】建立一种准确、快速测定香蕉果实单胺类及其前体物质(Monoamines and their precursors,MAPs)的方法,明确香蕉果实发育过程中MAPs各组分的含量变化规律,为下一步解析其合成代谢机理提供参考依据。【方法】以巴西香蕉、粉杂1号粉蕉和东莞大蕉3个香蕉品种的果实为试验材料,采用反相高效液相色谱—紫外检测(RPHPLC-UV)方法测定断蕾后15~75 d的果肉和果皮中MAPs含量,研究其在香蕉果实发育过程中的变化规律。【结果】RP-HPLC-UV色谱条件:采用C_(18)色谱柱(4.6×250 mm,5μm),甲醇为流动相A、0.1%三氟乙酸水溶液为流动相B,定量检测到去甲肾上腺素(NE)、多巴胺(DA)、左旋多巴(L-dopa)、酪胺(TYRA)、酪氨酸(Tyr)、血清素(SERO)、色胺(TRM)和色氨酸(Trp)等8种MAPs含量。其加标回收率为95.3%~106.1%;日内精密度范围为0.37%~0.82%,日间精密度范围为0.35%~0.83%;检测限为0.0012~0.0016 mg/100 g,定量限为0.0040~0.0053 mg/100 g;一个样品在14 min内可以完成检测。3个香蕉品种果实发育过程中,果皮TRM、TYRA、L-dopa、NE和DA含量均高于果肉。东莞大蕉和粉杂1号粉蕉果皮中SERO、Trp和Tyr含量高于果肉,而巴西香蕉果皮中Trp和Tyr含量低于果肉。在果实发育前期,巴西香蕉果肉中大部分MAPs物质的含量有一个快速升高的过程,在断蕾后30 d达峰值,NE、DA、TYRA、Tyr、Trp和TRM含量分别为22.14、239.81、118.29、43.74、46.41和5.33 mg/100 g,之后含量持续下降,NE、DA、TYRA和TRM在果实成熟时达最低值,含量分别为3.17、7.08、12.58和1.04 mg/100 g,而Tyr和Trp含量最低值出现在断蕾后45 d。东莞大蕉和粉杂1号粉蕉中TYRA和SERO含量在果实发育过程中呈下降趋势。【结论】建立的RP-HPLC-UV方法准确、灵敏、快速,可用于香蕉果实中MAPs的定量检测;3个香蕉品种不同发育阶段的果肉和果皮中均可检测到NE、DA、L-dopa、TYRA、Tyr、SERO、TRM和Trp等8种MAPs物质,且其含量在巴西香蕉果实中表现出区别于东莞大蕉和粉杂1号粉蕉的变化规律。

【Objective】To establish an method for accurate and rapid determination of monoamines and their precursors(MAPs)in banana fruit,to clarify the changes in the content of MAPs components during banana fruit development,so as to provide reference for analyzing its anabolic mechanism in the next step.【Method】Bnana fruits of three banana varieties,Baxi,Dongguan Dajiao and Fenza 1 were taken as tested material.The reversed-phase high performance liquid chromatography-ultraviolet(RP-HPLC-UV)was used to determine the contents of MAPs in pulp and peel of Baxi,Fenza1 and Dongguan Dajiao were detected from 15 to 75 days after cutting bud,to study how MAPs changed during the fruit development.【Result】A C_(18)column(4.6×250 mm,5μm)was connected to the RP-HPLC-UV platform.Methanol and0.1%trifluoroacetic acid aqueous solution were used as mobile phase A and B respectively.Then the contents of norepinephrine(NE),dopamine(DA),levodopa(L-dopa),tyramine(TYRA),tyrosine(Tyr),serotonin(SERO),tryptamine(TRM)and tryptophan(Trp)were determined.The spiked recoveries range was 95.3%to 106.1%,the intra-day precision ranges was 0.37%to 0.82%,and the inter-day precision ranges was 0.35%to 0.83%;the detection limit was 0.0012 to0.0016 mg/100 g,the limit of quantification was 0.0040 to 0.0053 mg/100 g;a sample can be completely detected within14 minutes.During fruit development of the three banana varieties,the contents of TRM,TYRA,L-dopa,NE and DA in the peel were higher than those in the pulp.In addition,the contents of SERO,Trp and Tyr in the peels of Dongguan Dajiao and Fenza 1 were higher than those in the pulp,while the contents of Trp and Tyr in the peels of Baxi were lower than those in the pulp.The contents of most MAPs increased rapidly in the early stage of fruit development in Baxi pulp,reaching the peak around 30 days after cutting bud,the contents of NE,DA,TYRA,Tyr,Trp and TRM were 22.14,239.81,118.29,43.74,46.41 and 5.33 mg/100 g.After that,the contents of NE,DA,TYRA and TRM reached the lowest point when the fruit matured,and the contents were 3.17,7.08,12.58 and 1.04 mg/100 g,respectively.However,the lowest point contents of Tyr and Trp appeared around 45 days after cutting bud.The contents of TYRA and SERO in Dongguan Dajiao and Fenza 1 showed a downward trend during fruit development.【Conclusion】An accurate,sensitive and rapid RP-HPLC-UV method is established,which can be used for quantitative detection of MAPs in banana fruits.8 MAPs,such as NE,DA,Ldopa,TYRA,Tyr,SERO,TRM,Trp were detected in the flesh and peel of three banana varieties at different developmental stages,and their contents in the fruit of Baxi show a significant difference from that of Dongguan Dajiao and Fenza 1.