"Determining Plant Seed Oleosome Size Distributions at the Single-Particle Level by Flow Cytometry"
Oleosomes are natural oil droplets found primarily in plant seeds, representing 20–50% of the seed’s total mass. Their function is to store energy as lipids and protect these stored lipids from the surrounding environment. Oleosome size is important because it can influence their stability and behavior in applications such as food, cosmetics, and drug delivery. However, many methods used to measure particle size provide only an average size or examine a small number of oleosomes. This makes it difficult to characterize the full range of oleosome sizes within a sample. In this study, we used flow cytometry to measure light scattered by individual oleosomes isolated from sunflower, soybean, and rapeseed. Light scattering theory and calibration with particles of known sizes were used to relate the scattered light signals to oleosome size. This method enabled the analysis of thousands of individual oleosomes and characterization of the size distributions within each sample. The average oleosome radii were 0.85 µm for sunflower, 0.75 µm for soybean, and 0.99 µm for rapeseed. Compared with fluorescence microscopy, flow cytometry allows a much larger number of particles to be analyzed and smaller oleosomes to be detected. Overall, this study demonstrates that flow cytometry can provide a rapid and quantitative method for measuring oleosome size and can be useful for studying oleosome structure and stability.