An antiflocculation/settling agent is manufactured with a method having a low cost and low environmental impact, the agent having a high level of safety and no taste, and having an inhibitory effect on flocculation/settling of a food or beverage. Also, to make effective use of yeast cell body residue produced as a byproduct of yeast extract. Yeast cell body residue remaining after removal of useful extract from yeast is suspended in water and heated, after which the suspension is subjected to centrifugal separation and supernatant is collected. This fraction contains at least 15 wt % RNA content per solid content, at least 10 wt % dietary fiber content, and at least 15 wt % protein content, and mannan makes up at least 50 wt % of the dietary fiber. This fraction can be used as an antiflocculation/settling agent in foods and beverages.
