How Mucilaginous Seeds of Different Plant Species Respond to Nonthermal Atmospheric Plasma Treatment

Important representatives of mucilaginous seeds from different plant species, namely amaranth (Amaranthus hypochondriacus L.), garden cress (Lepidium sativum L.), common flax (Linum usitatissimum L.), psyllium (Plantago ovata Forssk.), and chia (Salvia hispanica L.) were subjected to non-thermal plasma (NTP) generated by diffuse coplanar surface barrier discharge with different exposure times (1, 3, 5, 10, 20, 30 s). Seed water uptake, kinematic viscosity, parameters of seed germination and initial seedling growth were monitored along with chemical and morphological changes on the seed surface. Water absorption increased with increasing plasma exposure time for garden cress, psyllium and chia seeds, but it was greatest for chia seeds. For all seed species, the kinematic viscosity decreased with increasing plasma exposure time. The highest values were found for chia seeds after a treatment for 30 s. Surface analyses did not reveal any chemical and morphological changes of the seed surface. According to a PCA comparison of basic characteristics of germination and initial growth, common flax seeds differ in their reaction to NTP from the other tested plants. On the contrary, chia seeds showed the best water uptake and kinematic viscosity. It was shown that NTP treatment improves the absorption of mucilaginous seeds and does not change the surface and structural properties of the seeds. These mucilaginous seeds can be used as raw seed, whereby NTP accelerates their preparation during soaking.