Post-harvest Biology and Storage of Fruits and Vegetables Laboratory, Department of Food Science, Shenyang Agriculture University, Shenyang City, China.
Rapid Commun Mass Spectrom. 2021 Sep 30;35(18):e9146. doi: 10.1002/rcm.9146.
As important components of plant cells, lipids are involved in various biological functions. However, the composition and content of lipids in cell membranes changes at low temperature resulting in chilling injury and affecting the commercial value of green peppers. Detecting the changes in lipids helps to understand the mechanism of low-temperature stress in green peppers; however, a comprehensive study of lipid profiles in green pepper has not been well documented.
Herein, we report an ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/QTOF MS) method to determine phospholipids and glycolipids in green peppers and compare five extraction methods among which the isopropanol/chloroform/water (ICW) method demonstrated the best extraction efficiency. The established method was used to determine the membrane lipids of fresh samples, chilled samples(4°C-20d), and control samples (10°C-20d).
A total of 98 lipids, including 77 phospholipids and 21 glycolipids, were extracted from green peppers using ICW extraction. The content and profile of phosphatidylcholine (PC) among phospholipids were found to be the highest, accounting for 58.58% of all the phospholipids. The monogalactosyldiacylglycerol (MGDG) content among the glycolipids was the highest, accounting for 1.43%. The samples stored at low temperature (4°C, 20d) had a significantly higher PC content and a higher content of lipids containing unsaturated fatty acid residues as compared with the control samples (10°C, 20d). The recovery ranged from 75.55% to 96.64% while the limit of quantification ranged from 10 to 1000 ng mL .
The results indicated that the established method provided a reliable platform to study the changes in membrane lipids of a green pepper under low-temperature conditions.
脂质作为植物细胞的重要组成部分，参与各种生物功能。然而，细胞膜中的脂质组成和含量会随温度降低而发生变化，导致辣椒遭受冷害，从而影响辣椒的商业价值。检测脂质的变化有助于了解辣椒低温胁迫的机制；然而，目前尚未很好地记录辣椒脂质图谱的综合研究。
本研究采用超高效液相色谱/四极杆飞行时间质谱（UPLC/QTOF MS）法测定辣椒中的磷脂和糖脂，并比较了其中五种提取方法，结果表明异丙醇/氯仿/水（ICW）法的提取效率最高。该方法用于测定新鲜样品、冷藏样品（4°C-20d）和对照样品（10°C-20d）的膜脂。
采用 ICW 提取法从辣椒中提取了 98 种脂质，包括 77 种磷脂和 21 种糖脂。在磷脂中，磷脂酰胆碱（PC）的含量和种类最高，占所有磷脂的 58.58%。在糖脂中，单半乳糖二酰基甘油（MGDG）的含量最高，占 1.43%。与对照样品（10°C-20d）相比，低温（4°C，20d）储存的样品中 PC 含量更高，含有不饱和脂肪酸残基的脂质含量更高。回收率在 75.55%至 96.64%之间，定量下限在 10 至 1000ng mL 之间。
该研究建立的方法为研究低温条件下辣椒膜脂的变化提供了可靠的平台。
