Unconventional sourced proteins in 3D and 4D food printing: Is it the future of food processing?

[Display omitted] •Food industry shifts towards unconventional proteins for sustainability.•3D/4D printing offers potential to enhance food processing efficiency.•Limited exploration of 3D/4D printing with unconventional proteins.•Understanding rheological properties crucial for stable food printing.•Enhanced regulations vital to ensure safety in printed food products. Following consumer trends and market needs, the food industry has expanded the use of unconventional sources to obtain proteins. In parallel, 3D and 4D food printing have emerged with the potential to enhance food processing. While 3D and 4D printing technologies show promising prospects for improving the performance and applicability of unconventional sourced proteins (USP) in food, this combination remains relatively unexplored. This review aims to provide an overview of the application of USP in 3D and 4D printing, focusing on their primary sources, composition, rheological, and technical-functional properties. The drawbacks, challenges, potentialities, and prospects of these technologies in food processing are also examined. This review underscores the current necessity for greater regulation of food products processed by 3D and 4D printing. The data presented here indicate that 3D and 4D printing represent viable, sustainable, and innovative alternatives for the food industry, emphasizing the potential for further exploration of 4D printing in food processing. Additional studies are warranted to explore their application with unconventional proteins.