Abstract: In this experiment, pH-differential method and fully automatic colorimeter combined with degradation kinetics model were used to study the effects of low acyl (LA) and high acyl (HA) gellan gum on the thermal stability of anthocyanins from passion fruit peel (PFP) in model beverages with the presence of ascorbic acid, which were heat-treated at 85℃ for 0, 1, 2, 3, 4 and 5 hours. The components of anthocyanins of passion fruit peel were identified by ultra performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). The results showed that during the heat treatment, the anthocyanin content in the four model beverage systems， PFP, PFP+Vc, PFP+Vc+LA and PFP+Vc+HA, showed a downward trend, and the degradation of anthocyanins conformed to the first-order kinetic model. The half-lives were 308.44 days, 155.09 days, 189.69 days and 217.92 days respectively; low concentration (0.2%~0.5%) of gellan gum could improve the stability of anthocyanins, and the interaction between HA and anthocyanin was stronger than LA; During the heating period of 1~5h, the L* value increased significantly, the a* and b* values decreased significantly (P＜0.05), anthocyanins showed the phenomenon of extensive fading ,but it is slower than the fading reaction of 0~1h. That is, the four model beverage systems showed brightening, reddish, and yellow deepening，and anthocyanins from passion fruit peel showed extensive discoloration.; Four anthocyanins were identified from the passion fruit peel, namely cyanidin-3-glucoside, cyanidin-3-glucose, cyanidin-3-rutinoside and paeoniflorin-3-glucoside.

Key words: low acyl gellan gum, high acyl gellan gum, ascorbic acid, passion fruit peel, anthocyanin, thermal stability