Abstract: Gardenia blue was made from exhausted solution of gardenia yellow by the two-stage method,in which β-glucosidase fermentation and enzymatic reaction are separated.The effects of temperature,time and added ratio of amino acid on gardenia blue formation.The results induced that the best production process of gardenia blue is as follows:producing β-glucosidase from bran solid medium by Aspergillus niger fermentation,then hydrolyzing gardenoside by the β-glucosidase at 60 ℃ to produce gardenosin.By adding 1% histidine into the gardenosin solution and then bathing the mixture at 80 ℃ for 5 h,and the maximum formation amount of gardenia blue is achieved.

Key words: gardenia blue, pigment, fermentation