Water-Insoluble Dietary Fiber for Jelly Drink

For a powdered drink mix where you want a water-insoluble dietary fiber that swells into a jelly-like texture, Calcium Alginate (E404) is a suitable option.

Calcium Alginate is derived from seaweed and is specifically noted as being insoluble in water. While its description is brief, alginates are known for their gelling properties, and Calcium Alginate forms an insoluble gel structure, which can provide the desired wobbly or jelly-like texture suspended in the drink.

Other ingredients like Sodium Alginate and Guar Gum are water-soluble thickeners or gelling agents that create a viscous solution or a dissolved gel, rather than insoluble jelly pieces floating in the liquid, which seems to be what you are looking for.