## 3 Results and Discussion  
### Polyphenic Compounds, Antioxidant Activity and Potential Bioaccessibility  
The results for total phenolics content (TPC) and for the potential bioaccessibility of polyphenolic compounds after in vitro digestion are presented in Figure 1A. The TPC was statistically significant for the chosen plant seeds and algae (Figure 1A). The TPC ranged from 29.44 to 1635 mg GAE/g DM. In order, TPC was highest in star anise, followed by milk thistle, white mustard and fenugreek, and the lowest content was noted in white sesame, almonds, eggfruit, spirulina and chlorella. The TPC analyzed in all plant seeds and algae was similar to data from previous studies [31, 32, 33, 34]. The TPC in fenugreek was around give times higher, and that in white sesame seeds was around eight times lower, than the results obtained by [PERSON] [35] and [PERSON] et al. [36]. Generally, differences in the results for TPC were likely due to genotypic and environmental differences, such as temperature, climate, location, pest exposure, diseases within analyzed species and determination methods [37]. Moreover, each plant seed and algae could generally contain different mixtures of polyphenols, which influenced the TPC [38]. After the in vitro analysis in a simulated digestive system, the highest potential bioaccessibility for the TPC among the tested plant seeds and algae was noted in white sesame, almonds, spirulina and chlorella. The TPC determined in fenugreek, white mustard, black cumin and eggfruit was also potentially bioaccessible, as their values were above 1 [25]. Among all the analyzed materials, star anise and milk thistle presented the lowest potential bioaccessibility for TPC after in vitro digestion. Thus, the best plant seeds for the production of new functional food were found to be white sesame, almond, spirulina and chlorella. However, fenugreek, white mustard, black cumin and eggfruit can also be added to new nutraceuticalI food, but their potential bioaccessibility indexes will depend on various factors; e.g., the type of food, the enriched matrix food, the interaction of polyphenic compounds with their chemical compounds and behavior of the ingredients in the digestive system [39]. The differences in the obtained values for the potential bioaccessibility of polyphenic compounds may have resulted from the quality of the polyphenic compounds. It has been previously found that the process of digestion itself can enhance the release of bioactive compounds, especially polyphenols [40; 41; 42], whereas the low relative bioaccessibility for the ingredients could suggest interactions with other components of the research material, such as proteins and/or enzymes in the digestive system [39]. The formation of protein-phenolic complexes can significantly affect protein hydrophobicity, structure and solubility, as well as the isoelectric point and thermal stability. Additionally, the combination of phenolic compounds with proteins may affect the blocking of various amino acid residues. Their complexation can also impact the bioaccessibility and antioxidant activity of phenolics [43]. The results for antioxidant activities (ABTS and FRAP assays), as well as the potential bioaccessibility of these activities after in vitro digestion, are presented in Figure 1B,C, respectively. The antioxidant capacity of the analyzed plant seeds and algae ranged from 0.01 (white sesame) to 1.79 \(\upmu\)mol/g DM (star anise) in the ABTS assay (Figure 1B) and from 0.24 (fenugreek) to 71.75 \(\upmu\)mol/g DM (star anise) in the FRAP assay (Figure 1C). Among the plants and algae, star anise, milk thistle and white mustard seeds showed the highest antioxidant capacity, whereas almond, spirulina and white sesame had the lowest in both tests. The high antioxidant activity in star anise, milk thistle and white mustard seeds was likely due to their having the highest TPC, as a positive linear correlation between TPC and antioxidant capacity in plant seeds and algae was observed.