Hydrogels and biohydrogels: investigation of origin of production, production methods, and application

Hydrogels, called "crosslinked 3D networks," are excellent biomaterials for various food, agriculture, pharmaceutical, biomedical and environmental applications owing to their hygroscopic nature, porous structure, stimuli-responsive, viscoelasticity, flexibility, versatility, absorbent property, and soft structure. Hydrogels based on biopolymers (polysaccharides/proteins) like chitosan, alginate, pectin, starch, collagen, gelatin, whey protein, soy, heteropolymer granules, etc., which are crosslinked physically or chemically, are typically preferable to synthetics due to their compatibility, sustainability, degradability, nontoxic, and non-immunogenic features. As a result, these characteristics make hydrogels ideal for various applications, such as packaging, bioactives encapsulation, functional foods, food preservation, pharmaceuticals, drug and cell delivery, preventing bleeding, and tissue regenerative. Hydrogels can also control and manipulate material characteristics by the response to external factors including light, pH, magnetic, temperature, enzyme, temperature, electricity, etc. Moreover, hydrogels show important physicochemical reactions when exposed to environmental stimuli reversibly; as a result, after the removal of stimuli, the hydrogels are able of return to their primary state. Nevertheless, in this study, the types of hydrogel beads, production methods, their properties and applications in the food, biomedicine, and pharmaceutical sciences have been reviewed and discussed.