To provide a method of reducing an intrinsic harsh/astringent taste of protamine and a protamine salt and effectively using a fat absorption suppressive effect of these. A complex is formed by reacting at least one of acidic macromolecular substances, such as alginate and polyglutamate, and gum arabic which are capable of forming a complex reducing harsh/astringent taste and dissociating protamine having a lipase inhibitory activity by pepsin treatment, with protamine or a protamine salt.