Alternative Protein Systems: A Bibliometric and Comparative Review of Sustainability, Functionality, and Future Food Systems.

The growing demand for sustainable protein sources has accelerated the development of plant-based, microbial, cultivated, and insect proteins. This review combines a systematic analysis of Scopus-indexed publications with bibliometric mapping in Biblioshiny and VOSviewer and a comparative synthesis across environmental, economic, technological, nutritional, and social dimensions. The bibliometric results show a shift from technology-specific studies toward sustainability, circular bioeconomy, life-cycle assessment, consumer acceptance, and protein-transition research. No platform consistently outperforms the others across all dimensions. Plant-based proteins are currently the most technologically mature and economically competitive; microbial proteins offer high resource efficiency and circularity; cultivated meat most closely reproduces conventional meat but remains constrained by cost and energy demand; and insect proteins support nutrient recycling but face persistent acceptance and regulatory barriers. The evidence indicates that future sustainable protein systems will depend on complementary rather than competing production platforms. Integrating these technologies according to their distinct functional and sustainability advantages provides a promising pathway toward resilient and resource-efficient food systems and offers a basis for research priorities, technology development, investment, and policy strategies supporting the global protein transition.