中国农业科学 ›› 2021, Vol. 54 ›› Issue (22): 4869-4879.doi: 10.3864/j.issn.0578-1752.2021.22.013

• 园艺 • 上一篇    下一篇

基于代谢组学分析丝瓜果肉褐变过程酚酸类物质变化

王雅慧1,2(),刘晓宏1,雍明丽1,熊爱生2,苏小俊1()   

  1. 1江苏省农业科学院蔬菜研究所/江苏省高效园艺作物遗传改良重点实验室,南京 210014
    2南京农业大学园艺学院/作物遗传与种质创新国家重点实验室/农业农村部华东地区园艺作物生物学与种质创制重点实验室,南京 210095
  • 收稿日期:2021-01-28 接受日期:2021-03-24 出版日期:2021-11-16 发布日期:2021-11-19
  • 通讯作者: 苏小俊
  • 作者简介:王雅慧,E-mail: 2019204036@njau.edu.cn
  • 基金资助:
    苏州市农业科技创新项目(农业关键技术应用研究)(SNG2018061);江苏省高校优势学科(PAPD)

Analysis of Changes in Phenolic Acids of Luffa cylindrica Pulp During Browning Based on Metabolomics

WANG YaHui1,2(),LIU XiaoHong1,YONG MingLi1,XIONG AiSheng2,SU XiaoJun1()   

  1. 1Institute of Vegetable Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014
    2College of Horticulture, Nanjing Agricultural University/State Key Laboratory of Crop Genetics and Germplasm Enhancement/Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Nanjing 210095
  • Received:2021-01-28 Accepted:2021-03-24 Online:2021-11-16 Published:2021-11-19
  • Contact: XiaoJun SU

摘要:

【目的】褐变是影响丝瓜商品价值的主要因素,酚酸类物质代谢是导致褐变的主要原因。研究丝瓜褐变过程酚酸类物质变化有助于深入了解丝瓜褐变的生理机制,为丝瓜的贮藏和加工、品种选育和种质资源利用提供依据。【方法】以耐褐变丝瓜品种‘2D-2’和易褐变丝瓜品种‘35D-7’为试验材料,测定其鲜切后放置不同时间的褐变程度、总酚含量和多酚氧化酶活性,并借助超高效液相色谱-质谱(UPLC-MS)联用的方法对沸水浴褐变前后的丝瓜果肉样品进行代谢组学分析。【结果】鲜切褐变处理后,2个品种丝瓜果肉中的多酚含量及多酚氧化酶活性均有所增加。与‘2D-2’相比,丝瓜品种‘35D-7’的褐变程度较重,放置24 h后的总酚含量约为‘2D-2’的3倍以上;多酚氧化酶活性在放置12 h时最高,达174.23 U·g-1·min-1。通过代谢组学对易褐变丝瓜品种‘35D-7’酶促褐变反应底物及褐变前后的差异代谢物进行分析,经检测共获得420种代谢物,其中229种为差异代谢物。经褐变处理后,140种差异代谢物含量显著下降,89种升高。KEGG通路富集分析结果表明,苯丙素类生物合成、脯氨酸代谢和类黄酮生物合成等代谢途径中的代谢物含量发生了显著变化。代谢组定性定量分析结果发现,供试样品丝瓜果肉中鉴定出的酚酸类物质中对香豆酸含量最高,其次是松柏苷和龙胆酸。经褐变处理后,共有35种差异代谢物被鉴定为酚酸类代谢物。其中,松柏醛、3-氨基水杨酸和咖啡酸苯乙酯的含量下降最明显。相反地,紫丁香苷、2,5-二羟基苯甲酸O-己糖苷和异绿原酸A的含量显著提高,log2变化倍数达10以上。【结论】易褐变丝瓜品种‘35D-7’果肉中的主要酚类物质为对香豆酸,参与丝瓜‘35D-7’果肉褐变过程的主要酚酸类代谢物有松柏醛、紫丁香苷和异绿原酸A等。

关键词: 丝瓜, 果肉, 酶促褐变, 代谢组, 酚酸

Abstract:

【Objective】Browning is the main element affecting the commercial value of Luffa cylindrica. The principal consideration of browning is linked to the metabolism of phenolic acids. Studying the changes of phenolic acid during the browning process of Luffa is helpful to understand the physiological mechanism of browning, so as to provide the basis for the storage and processing, breed selection and utilization of germplasm resources of Luffa. 【Method】Browning-resistant Luffa cultivar 2D-2 and browning-prone cultivar 35D-7 were used as experiment materials. Their browning degree, total phenol content and polyphenol oxidase activity after fresh cutting for different time were measured. Ultra high-performance liquid chromatography-mass spectrometry (UPLC-MS) was utilized to analyze the metabolomic of Luffa pulp before and after browning in boiling water bath. 【Result】 After fresh-cut browning treatment, the content of polyphenols and the polyphenol oxidase activity in the flesh of both two Luffa cultivars were increased. Luffa 35D-7 had severer browning degree. The total phenol content after 24 h storage was much more than 3 times of that of 2D-2, and the polyphenol oxidase activity achieved the top at 12 h, reaching 174.23 U·g-1·min-1. Based on metabolomics, the substrate of enzymatic browning reaction and the difference of metabolites in browning-prone Luffa 35D-7 before and after browning were analyzed. A total of 420 metabolites were detected, 229 of which were differential metabolites. After browning, the contents of 140 kinds of differential metabolites were substantially decreased, while 89 kinds were increased. KEGG pathway enrichment analysis demonstrated that metabolites related to phenylpropanoid biosynthesis, proline metabolism and flavonoid biosynthesis displayed significant changes. The results of qualitative and quantitative analysis of metabolomics suggested the content of p-coumaric acid was the highest in the phenolic acids identified in the flesh of the tested Luffa, followed by coniferin and gentisic acid. After browning treatment, 35 different metabolites were classified as phenolic acid metabolites. Among them, the content of coniferaldehyde, 3-aminosalicylic acid and phenethyl caffeate decreased most obviously, while the content of syringin, 2,5-dihydroxy benzoic acid O-hexside and isochlorogenic acid A increased significantly, and the log2 fold change was more than 10. 【Conclusion】The main phenolic substances in the flesh of 35D-7 were p-coumaric, and the main phenolic acid metabolites involved in the browning process of 35D-7 were coniferaldehyde, syringin and isochlorogenic acid A etc. The results could help further reveal the physiological mechanism of Luffa browning and provide basis for the improvement of Luffa variety.

Key words: Luffa, pulp, enzymatic browning, metabolomics, phenolic acids