Material and methods: The jackfruit seeds came from Thai jackfruits harvested from Hau Giang province, Vietnam. Jackfruit seed slides were roasted in a rotary drum roaster at temperatures of 160, 170, and 180°C for 30, 40, and 50 minutes after oven-drying for 90 minutes at 60°C. The functional properties, pasting properties, thermal properties, total phenolic content (TPC), antioxidant activity expressed through 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging, and the sensory attributes of the roasted samples were analyzed. 

Results: Roasting temperature and time significantly affected the quality of roasted jackfruit seed powder (RJSP). The high roasting temperature and time decreased bulk density (BD), tapped density (TD), foam capacity (FC), foam stability (FS), and viscosity properties of the powder. On the contrary, TPC, DPPH free radical scavenging, pasting temperature, and enthalpy for gelatinization significantly increased. A notable result was the formation of a chocolate aroma, notably when roasting jackfruit seeds at 170°C for 40 minutes. RJFS then exhibited high TPC (5.54 mg GAE/g) and antioxidant activity (DPPH free radical scavenging of 79.02%).

Conclusion: Temperature and time are important factors for the roasting process. Roasting jackfruit seed at 170°C for 40 minutes enhanced the chocolate aroma, antioxidant activity, and suitable functional properties for chocolate products.