INNOVATIVE LOW-HYDROPHILICITY BIOMATERIALS FROM BABASSU BY-PRODUCTS FOR PACKAGING APPLICATIONS

This study aimed to develop a bio-based film for food packaging using babassu by-products. A polymeric matrix was prepared with either babassu mesocarp flour (BF) alone (control) or a blend of BF and babassu cake supernatant (BCFS). Formulations were processed under two conditions: (i) at native pH (BF-BCFS) and (ii) with alkaline treatment using NaOH, resulting in BF12 and BF-BCFS12. Film-forming solutions were cast and dried at 35 °C. The films were characterized for colorimetry, opacity, morphology (MEV), thermal properties (DSC), chemical structure (FTIR), and surface wettability (WCA). Colorimetric analysis (L*, a*, b*, and C*) revealed distinct visual differences. Films without chemical treatment (BF and BF-BCFS) had higher L* (33.86^a and 28.26^b) and C* values (44.48^a and 34.56^b), indicating a lighter and more saturated appearance. Conversely, chemically treated films (BF12 and BF-BCFS 12) showed significantly lower L*, a*, and b* values, appearing darker and less saturated (lower C*: 0.46^c and 0.32^c), likely due to Maillard reactions and sugar caramelization caused by alkaline and thermal processing. ΔE values indicated substantial visual differences for BF 12 (46.74^c) and BF- BCFS 12 (46.54^a) compared to the control, while BF- BCFS showed moderate variation (12.19^b). BF and BF- BCFS remained orange-colored with moderate translucency (5. 18% and 7. 33%), whereas alkaline-treated films exhibited a black-brown color and were opaque. Morphological analysis showed similar surface features for BF and BF- BCFS, while BF 12 and BF- BCFS 12 had rougher surfaces, though their cross-sectional morphology remained comparable. FTIR spectra confirmed the presence of O–H, C–H, C=O, and C–O bonds, indicating proteins, saccharides, and lipids in all films. Alkaline treatment intensified amide and ester signals, especially in BF12 and BF-BCFS12, suggesting greater chemical modification beyond that from BCFS addition alone. DSC analysis revealed improved thermal stability in treated films, with BF12 showing higher Tg (76.28 °C) and enthalpy (ΔH = 325.5 J/g). BF-BCFS12 displayed multiple Tg points (up to 155.56 °C), likely due to complex molecular interactions. Surface wettability analysis indicated moderately hydrophilic behavior for BF and BF-BCFS (∼60°), which shifted to lower hydrophilicity (∼70°) in treated films, probably because of an increased presence of hydrophobic compounds. In conclusion, the alkaline treatment significantly affected the structural, thermal, and optical properties of the films, demonstrating promising potential for the customization of bio-based packaging materials from by-products of the babassu industry.