<p>Jackfruit seed is an underutilized part of jackfruit. The objective of the study is to extract and evaluate the physicochemical and functional properties of flour, starch, and protein from jackfruit seeds. The yield analysis revealed that flour had the highest yield (87.7%), followed by starch (28.2%) and protein (10.1%). In terms of color, starch exhibited the highest <i>L*</i> (98.22), followed by flour and protein. The gelatinization temperature was highest for starch (94.5 °C), followed by flour (79.60 °C), while the denaturation temperature of protein was 89.1 °C. Solubility was determined at different temperatures for starch and flour (55 °C–95 °C) where both starch and flour exhibited an increase in solubility with increased temperature, whereas protein solubility was about 77%. The increasing foaming capacity of the JSPI can be attributed to the increasing solubility. Protein demonstrated the highest foaming capacity (238.34%) and also emulsion capacity and stability (72.13%), whereas water absorption capacity and oil absorption capacity were highest in flour, followed by protein and starch. In terms of gelation properties, both in water and alkaline solutions, starch and flour exhibited gelation at 6%, while protein gelation occurred at 10% concentration. The starch exhibited the highest setback viscosity at 2337 ± 0.02 cP, indicating a lower susceptibility to retrogradation. The protein gel exhibited a G″/G′ ratio ranging from 0.022 (strongest gel) to 0.27 (weakest gel). SEM analysis showed a smooth surface for JSS and sheet-like structure of different sizes and shapes of JSPI.</p> Graphical Abstract <p></p>