Abstract: High performance liquid chromatography (HPLC) was used to determine naringin and hydrolysates in Guanxi pomelo juice to explore the optimal conditions of bitterness removal for Guanxi pomelo juice by the naringinase from Aspergillus niger DB056. Under optimized conditions, the naringinase was used to debitter Guanxi pomelo fresh fruit juice, cloudy concentrated juice and clarified concentrated juice. The results showed that the optimal debittering conditions were natural pH, 40－55 ℃treatment temperature, 90 U/mL naringinase amount and 80 min treatment time. Under the optimal debittering conditions, the naringin in pomelo juice could be effectively degraded into prunin and naringenin by the enzyme and the removal rate of naringin was up to 89%; meanwhile, the debittering efficiency of cloudy concentrated juice was up to 80%. Therefore, naringinase has an excellent debittering capability for Guanxi pomelo juice.

Key words: Aspergillus niger DB056, naringinase, Guanxi pomelo juice, HPLC, removal rate