Table_1_LC/MS- and GC/MS-based metabolomic profiling to determine changes in flavor quality and bioactive components of Phlebopus portentosus under low-temperature storage.docx

IntroductionLow temperature is the most common method used to maintain the freshness of Phlebopus portentosus during long-distance transportation. However, there is no information regarding the nutritional changes that occur in P. portentosus preserved postharvest in low temperature.
MethodsIn this study, the changes in flavor quality and bioactive components in fruiting bodies stored at 4 °C for different storage periods were determined through LC/MS and GC/MS analyses. Sampling was performed at 0, 3, 5, 7, and 13 days storage.
Results and DiscussionBased on the results, the metabolites present in caps and stipes were different at the same period and significantly different after 7 days of storage. A total of 583 and 500 different metabolites were detected in caps and stipes, respectively, and were mainly lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds and others. Except for prenol lipids and nucleotides, the expression levels of most metabolites increased with longer storage time. In addition, geosmin was identified as the major contributor to earthy-musty odors, and the level of geosmin was increased when the storage time was short.
ConclusionThe variations in these metabolites might cause changes in flavor quality and bioactive components in P. portentosus. Variations in these metabolites were thoroughly analyzed, and the results revealed how storage processes affect the postharvest quality of P. portentosus for the first time.

引言：低温是长距离运输过程中维持暗褐网柄牛肝菌（Phlebopus portentosus）鲜度最常用的手段。然而，目前尚无关于采后经低温保存的该菌营养成分变化的相关研究报道。材料与方法：本研究通过液相色谱-质谱联用（LC/MS）与气相色谱-质谱联用（GC/MS）分析技术，测定了4℃条件下不同贮藏时长的子实体风味品质与生物活性成分变化。分别在贮藏第0、3、5、7及13天进行取样。结果与讨论：分析结果显示，同一贮藏时期内，菌盖与菌柄中的代谢物组成存在差异，且贮藏7天后二者差异显著。本研究分别在菌盖与菌柄中检测到583种和500种差异代谢物，其主要类别为脂质及类脂质分子、有机酸及其衍生物、有机氧化合物等。除异戊烯醇脂质与核苷酸外，多数代谢物的含量随贮藏时长延长而升高。此外，土臭素（geosmin）被确定为产生土腥味的主要物质，且在贮藏初期其含量即有所上升。结论：上述代谢物的变化或导致暗褐网柄牛肝菌风味品质与生物活性成分发生改变。本研究对这些代谢物的变化进行了全面分析，首次揭示了贮藏过程如何影响该菌的采后品质。