Synthesis and quality evaluation of an edible film from coconut protein isolate: A sustainable packaging solution using coconut by-products

This research aims to develop an edible film as an alternative to petroleum-based packaging using coconut protein extracted from defatted coconut meal (DCM). Two types of matrix: coconut protein (CP) and corn starch (CS) 3%; two levels of pH: 8.5 and 9.5; two concentrations of polyethylene glycol (PEG): 2.5% and 0% and a constant volume of glycerol (10 ml of 20%) were used for film preparation using the casting method. The results showed that the extracted CP recovery is 23.99 ± 0.87% and it has 78.43% of protein content. CP films with 2.5% PEG showed a significantly (p < 0.05) high moisture content (49.20 ± 0.43%), and swelling index (483.96 ± 13.79%) at 8.5 pH, while significantly high solubility (76. 0 ± 1.4%) and thickness (0.33 ± 0.01 mm) at 9.5 pH. The CS film (pH 8.5 and 0% PEG) showed a significantly higher percentage of light transmission at 200 to 800 nm. The CP films showed higher degradability compared to CS films. A low concentration (10%) of glycerol significantly (p < 0.05) reduced rehydration (48.06 ± 4.47%) and the water uptake ratio (83.03 ± 7.93%) while increasing opacity (0.41 ± 0.079 mm −1 ) and lightness (38.31 ± 0.38). The study confirmed that the coconut protein (3%) with 10% glycerol at 8.5 pH can effectively form edible film for the food industry.