NMR Spectroscopy for Phospholipid Characterization

A current study focused on highlighting the growing importance of nuclear magnetic resonance (NMR) techniques in characterizing phospholipids (PLs) in food. This study, which was published in the Journal of Food Composition and Analysis, was led by De-Wei Chen of Guangxi University and the Key Laboratory of Deep Processing and Safety Control for Specialty Agricultural Products in Guangxi Universities (1). In the study, Chen and his team dissected the various NMR techniques that have been applied in PL analysis, explaining what information each of these techniques provides. Through these explanations, the authors show how NMR may be an effective tool for routine PL analysis.

Microscopic view of a cell membrane with intricate network of proteins and signaling pathways. Generated with AI. | Image Credit: © Vibudhaart - stock.adobe.com

PLs consist of lipid bilayers, and their purpose is to protect cells against environmental factors (2). They play an important role in food composition because they can influence the texture and nutritional quality of the food product (1,2). As a result, manufacturers have good reason to understand their structural composition during food processing. The issue that currently exists is that many analytical methods are unable to effectively characterize PLs in complex food matrices (1).

In this review article, Chen and his coauthors go over the NMR techniques that may be able to characterize PLs in food matrices. Each section of their article concentrates on a specific NMR technique. Among the various NMR techniques, phosphorus-31 NMR (³¹P NMR) spectroscopy can detect phosphorus-containing compounds, eliminating interference from non-phosphorus components such as triglycerides (TG) (1). This specificity ensures high analytical accuracy and efficiency, making it a preferred tool for quantifying and qualifying PL in food samples (1). Furthermore, ³¹P NMR offers shorter relaxation times, improving measurement speed without compromising precision (1).

Another NMR technique that can distinguish PL components, acyl groups, and oxidation compounds is proton NMR (¹H NMR) (1). The ability of ¹H NMR to simultaneously monitor primary, secondary, and advanced oxidation products makes it invaluable for assessing PL degradation during food processing and storage (1). Because food scientists like to try and increase the shelf life of their food products, ¹H NMR is a technique that can be used to help with this.

Another NMR technique, Carbon-13 NMR (¹³C NMR), provides additional structural insights. In particular, ¹³C NMR spectroscopy can be used to determine lipid classes, acyl group distribution, and fatty acid positional arrangements within PL (1). Meanwhile, two-dimensional (2D) NMR techniques have gained attention for their ability to reliably identify and quantify PL, especially minor components in complex food matrices (1). However, despite its advantages, 2D NMR remains underutilized in food science because of its lower sensitivity compared to mass spectrometry (MS) (1).

The final NMR technique discussed was solid-state NMR (ssNMR). This technique has been used to study intact food systems, providing valuable information on PL composition and structural changes during food processing (1). Notably, ssNMR can use PL as both a ¹H and ³¹P probe to characterize various food structures (1). However, Chen and his colleagues acknowledge that using ssNMR in food science lags behind its use in biological research (1).

After reviewing the various NMR techniques, the researchers conclude that NMR has a promising future in characterizing PLs and in food analysis more broadly. Because NMR spectroscopy is a non-destructive, highly reproducible, and labor-efficient analytical tool, researchers explain, it can provide direct quantitative insights into PL composition and dynamics (1). Its broad applicability and ability to offer detailed molecular-level data make it a potentially valuable technique in food research (1). Moving forward, advancements in sensitivity and standardization will be crucial for integrating NMR more extensively into routine food analysis.

References

1. Chen, D.-W.; Mo, X.; Xiao, J.; Zhao, Z.; Wang, P. Use of Nuclear Magnetic Resonance Spectroscopy to Identify Phospholipids in Food: A Brief Review. J. Food Comp. Anal. 2025, 140, 107268. DOI: 10.1016/j.jfca.2025.107268
2. Dai, Y.; Tang, H.; Pang, S. The Crucial Roles of Phospholipids in Aging and Lifespan Regulation. Front. Physiol. 2021, 12, 775648. DOI: 10.3389/fphys.2021.775648