What this work is about, in plain words
How resistant is the pigment fucoxanthin to irradiation? The authors studied extracts of the diatom Cylindrotheca closterium and found that in the presence of oxygen the pigment partly recovers after irradiation.
Raw materials and preparations from algae are often sterilized by irradiation. So it is important to know how irradiation affects valuable substances, above all the pigment fucoxanthin. The authors studied the optical properties of alcoholic and acetone extracts of the diatom Cylindrotheca closterium and their resistance to gamma radiation.
Extracts were prepared from the biomass with different solvents, and the distribution of pigments — carotenoids and chlorophylls — in them was studied. Fucoxanthin solutions were then irradiated with different doses with and without access to air, and changes in the spectra were monitored.
According to the authors, the choice of solvent affects the yield of pigments. The dependence of fucoxanthin stability on the radiation dose is complex, especially at low doses. With access to oxygen, the pigment was more stable than without it: after irradiation it partly recovered. A similar effect had previously been observed in the brown seaweed Cystoseira.
In practice, this means that the irradiation sterilization regime must be chosen with the conditions in mind, or part of the pigment may be lost.
Limitations. This is a physicochemical study of extracts. The biological activity of the pigments was not tested in the work.