Water-Insoluble Films from Upcycled Babassu Coconut Byproducts: An Alternative Material for Single-Use Oil Sachets

This research presents the development of an innovative water-insoluble film intended for use as an oil sachet. A polymeric matrix composed of babassu mesocarp flour, or its blend with babassu cake supernatant, was prepared at both native pH and pH 12. The alkaline treatment combined with supernatant (BF-BCFS12) significantly enhanced the crystallinity index (reducing from 7.35% to 3.21%), heat resistance (increasing from 57.56 to 71.25 °C), solubility (increasing from 0.14% to 1.23%), and luminosity (decreasing from 33.86 to 20.43) in comparison to the pure mesocarp film. An innovative permeability evaluation conducted using cream crackers indicated that the alkali-treated films preserved texture more effectively than the original packaging. The antiultraviolet property emerged as a critical factor in selecting BF-BCFS12 as a sachet for soybean and olive oils stored for 6 days under conditions conducive to oxidation (50 ± 2 °C under light at a distance of 6 cm). The surface wettability of BF-BCFS12 exhibited moderate hydrophilicity in water (approximately 60°) and lipophilicity in oil (less than 17°). The sachet demonstrated an initial strength of 83.32 N, and after 6 days, the peroxide value of soybean oil was found to be 1.45 times higher, while that of olive oil was 2.8 times lower than that observed in the original package, with acidity and color differences remaining unchanged. To our knowledge, this is the first study to incorporate babassu cake into a polymer blend film.