That touch of blue is the color created by "grease"
That touch of blue is the color created by "grease"
Charming structural color

(first on fruit shell Weibo)

you may never have seen such a beautiful "grease".

Large varieties of shapes and cuts for you to choose from.

the Mediterranean pod (Viburnum tinus) has small blue fruits that may look a bit like blueberries at first glance. However, the metallic blue of these fruits is actually quite different from the blue source of blueberries-it is a structural color and is produced through lipid structure.

cut open the blue skin of the Mediterranean pod fruit and observe them under a microscope. The researchers found that there was a special structure hidden in the cell wall of the exocarp: there were many parallel layers of vesicles in the middle of the cell wall matrix. The vesicle layer with different refractive index is staggered with the cellulose matrix layer, so the multi-layer structure can make the reflected light of each interface interfere with each other, and the bright blue is born.

(the peel produces a blue optical structure (3D reconstruction)

A series of staining and organic solvent tests show that these vesicles used to form structural colors contain lipids-to be exact, more likely to be free fatty acids. This is the first time that lipids have been found to be used to produce structural colors in organisms.

however, there is no specific chemical analysis of lipid composition in this study.