The present invention relates to a powdered brown alga that includes a water-soluble algin and an insoluble component, with a ratio by weight of the water-soluble algin to the insoluble component of 1:0.05 to 1:4. The present invention also relates to a suspending agent using the powdered brown alga, a solution containing precipitate particles using the suspending agent, and a suspension method and a food-product improvement agent using the powdered brown alga, a food product using the food-improvement agent, and a method for manufacturing the food product.