PROBLEM TO BE SOLVED: To provide a method for producing a gardenia blue pigment which can maintain the state of being stably dissolved in an acidic region.SOLUTION: A method for producing a gardenia blue pigment comprises the step of applying β-glucosidase treatment to an iridoid glycoside in the presence of a silk-derived protein decomposition product.SELECTED DRAWING: NoneCOPYRIGHT: (C)2017,JPO&INPIT【課題】酸性域で安定に溶解した状態を維持できるクチナシ青色素の製造方法を提供する。【解決手段】シルク由来のタンパク質分解物の存在下でイリドイド配糖体をβ-グルコシダーゼ処理する工程を含むクチナシ青色素の製造方法。【選択図】 なし