Hydrogel fabrication using emerging technologies: Sources, mechanisms, and food applications

Hydrogels are three-dimensional networks of crosslinked polymer chains dispersed within an aqueous matrix, extensively employed in the food, biomedical, and pharmaceutical industries due to their high water-holding capacity and tunable functional properties. Conventional hydrogel fabrication methods rely on heat, ions, and enzymes, and are widely used but often suffer from limitations such as high energy requirements and limited control over the gel structure. In recent years, non-thermal technologies have gained attention as promising alternatives to conventional methods in hydrogel fabrication. These novel techniques, including high-pressure processing, ultrasound, cold plasma, moderate electric field, and ionizing radiation, offer significant advantages such as enhanced structural integrity, reduced processing time, and improved energy efficiency. Each technology operates through distinct physicochemical mechanisms that influence polymer interactions, crosslinking density, and the resulting compact gel network. This review provides a comprehensive overview of hydrogel sources and different fabrication methods, followed by a detailed comparison of conventional and emerging processing techniques. Emphasis is placed on the mechanistic insights of novel technologies and their influence on key hydrogel properties, including mechanical strength, swelling behaviour, porosity, and stability. In the food industry, hydrogels fulfil multifunctional roles as texture modifiers, fat replacers, delivery systems for nutraceuticals, smart packaging materials, and biosensing platforms. The ability of emerging technologies to tailor hydrogel characteristics holds great potential for the development of next-generation functional food systems. However, the implementation of these emerging technologies in hydrogel fabrication faces several limitations, including initial capital investment, the requirement for technically skilled personnel, and challenges associated with large-scale industrial scalability.