Valorization of poultry slaughter wastes via extraction of three structural proteins (gelatin, collagen and keratin): A sustainable approach for circular economy

Background: The burgeoning demands for protein with the increasing population is not only for its nutritive value but also for its physiochemical and functional characteristics. To address these growing demands for protein, a rapid surge in the poultry sector occurred which resulted in the production of huge quantities of poultry slaughter wastes on a daily basis. The conventional methods of dealing with these wastes are incineration, composting, fertilizer manufacturing and bird or fish meals production, which were reported to have deleterious effects on the environment like air and water pollution, greenhouse gas emission and eutrophication. Furthermore, the scientific community is looking for some alternatives to the mammalian sources of protein to sustain the growing world population in the face of climate change. Poultry slaughter wastes present a potential alternate which can be explored to address the above-mentioned issues. Scope and approach: This review explains the characteristics of structural proteins (collagen, gelatin and keratin) extracted from poultry waste with respect to extraction methods. Additionally, this study elaborates the applications of extracted proteins in various industrial sectors and presents a potential approach in line with the concept of circular economy. Key findings and conclusions: Poultry wastes are a potential source to be explored for the extraction of proteins. The proteins extracted from poultry wastes are similar or better to their bovine counterparts in terms of thermal stability, nutrition, amino acid content, physiochemical, rheological and functional properties.