## 4 Conclusions  
In conclusion, the results from this study directly address the growing demand for natural and multifunctional ingredients in the cosmetic industry. PBP are highly valued for their vibrant colour and potent antioxidant properties, making them ideal candidates for skin care and cosmetic formulations. This study's optimised extraction and purification workflow produced PC and APC extracts with high recovery and purity while retaining strong antioxidant capacity, as confirmed by the Folin-Ciocalteu and ABTS\({}^{\bullet+}\) assays. These results highlight the suitability of these extracts for incorporation into cosmetic products where they could serve a dual function as antioxidants and colourants. Overall, this research demonstrates the feasibility of using conventional, scalable methods to produce cosmetic-grade PBP, offering a sustainable and cost-efficient solution for the cosmetics industry. Moreover, the study validated the antioxidant properties of PBP for functional applications and addresses the industry's increasing focus on eco-friendly and natural alternatives to synthetic ingredients. Future efforts should focus on integrating these extracts and evaluating their functionality in cosmetic formulations. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15020532/s1](https://www.mdpi.com/article/10.3390/app15020532/s1)]([https://www.mdpi.com/article/10.3390/app15020532/s1](https://www.mdpi.com/article/10.3390/app15020532/s1)), Figure S1: Schematic diagram outlining the performed extractions of this study. **Author Contributions:** Conceptualisation: M.S. ; methodology: U.K., S.A., V.K.-S. and M.S. ; formal analysis: U.K. and S.A.; investigation, U.K. and S.A.; resources: M.S. ; data curation: V.K.-S. and M.S. ; Validation: V.K.-S. and S.A.; writing--original draft preparation: U.K.; writing--review and editing: S.A., V.K.-S. and M.S. ; supervision: M.S. and V.K.-S.; Funding acquisition: M.S. Project administration: M.S. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the Research Council of Lithuania (RCL), Project no. : S-MIP-23-78: Projects carried out by researchers' teams. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy. **Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the study's design, data collection, analysis, interpretation, manuscript writing, or decision to publish the results. * _[PERSON]_ _et al._ (2021) [PERSON]; [PERSON]; [PERSON]; [PERSON] Phycocyanin from Spirulina: A Review of Extraction Methods and Stability. _Food Res. Int._**2021**, _143_, 110314. [CrossRef]
* _[PERSON]_ _et al._ (2024) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Advanced Methods of Algal Pigments Extraction: A Review. _Crit. Rev. Food Sci. Nutr._**2024**, _64_, 9771-9788. [CrossRef] [PubMed]
* _[PERSON]_ _et al._ (2022) [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] Pulsed Electric Fields Assisted Extraction of Proteins and Phycocyanin from _Arthospira platensis_ Biomass: A Kinetic Study. _Food Bioprad. Process._**2022**, _147_, 304-314. [CrossRef]
* _[PERSON]_ _et al._ (2024) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] Extraction of Phycocyanin and Chlorophyll from _Spinulina_ by \"Green Methods\". _Separations_**2024**, _11_, 57. [CrossRef]
* _[PERSON]_ _et al._ (2017) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] Advancement of Green Process through Microwave-Assisted Extraction of Bioactive Metabolites from _Arthospira platensis_ and Bioactivity Evaluation.