The environmental impact of polystyrene and other petrochemical packaging has increased interest in researching biodegradable materials as alternatives. The main objective of this research was to develop biodegradable trays from five formulations of Poraqueiba sericea Tulasne (known as umari) seed starch and corncob meal. The trays were produced using the thermoforming process applying temperatures of 135 °C and 145 °C for each side of the tray for a time of 6.5 min. Physical analysis of the trays showed that the increase in the percentage of corn cob flour caused changes in color (L*: 68.69 - 64.94), thickness (2.20 - 3.17 mm), density (0.251 - 0.414 g/cm3), moisture (3.85% - 5.68%), water absorption (21.86% - 39.05%), volatile solids (95.33% - 98.31%). Regarding mechanical properties, it was also evidenced the increase in hardness (67.70 - 90.97 N), fracturability (1.43 and 3.19 mm),...