Abstract
Films were produced from babassu mesocarp flour (BM) and from a composite with BM cake (BMC), a by-product of oil extraction; both were subjected to alkaline and hydrothermal treatments. The films were tested as sachets for packaging an artisanal ora-pro-nóbis pesto. BMC films exhibited higher mechanical strength, with a tensile strength of 2.20 MPa and a Young's modulus of 4.29 MPa. In contrast, BM films reached an elongation of 38.3%. Both films were uniform, dark black in color, provided approximately 98% ultraviolet (UV) shielding, completely biodegraded in soil within 90 days, and were non-toxic to bean seeds. BMC, in particular, acted as a more effective biofertilizer and promoted germination by 93% with a germination rate index of 13.39 seeds/day. In an aqueous environment, both films decomposed similarly in freshwater (∼6.3% after 14 days), although BMC decomposed more in seawater (5.95%) than BM (0.13%). Antimicrobial testing showed that BM inhibited Listeria monocytogenes and Pseudomonas aeruginosa at a minimum inhibitory concentration of 6.25 µL/mL, whereas BMC was also effective against Campylobacter jejuni, requiring only 3.125 µL/mL to inhibit L. monocytogenes. As pesto sachets, the BMC films maintained their microbiological safety and consumer acceptability for 4 days at 4°C and 25°C and showed a high puncture resistance of 27.5 N despite minor pH and color changes. Overall, the BMC sachets proved to be a biocompostable alternative for single-use packaging of oily sauces, adding value to by-products in the context of a circular bioeconomy.