Sona Dodange, Hajar Shekarchizadeh
The production of human food generates substantial amounts of by-products and waste, creating both economic and environmental challenges. Many of these by-products contain valuable compounds, particularly proteins, which have gained increasing attention due to their nutritional and functional potential. Proteins, peptides, concentrates, and hydrolysates derived from food processing by-products exhibit diverse bioactivities and can be used in food enrichment, dietary supplements, packaging materials, and biomedical applications. While most existing studies primarily focus on extraction technologies, the present review addresses an important gap by providing an integrated synthesis of the applications, functional properties, and cross-sector uses of protein-derived compounds obtained from both animal- and plant-based by-products. Additionally, key challenges related to industrial scalability, regulatory frameworks, and consumer acceptance are discussed. Overall, valorizing protein-rich food by-products represents a promising strategy for sustainable waste management and resource optimization. However, further research is required to improve extraction efficiency, assess safety and stability, and support large-scale industrial implementation.