Abstract:
The objective of this research was to determine the optimal condition for synthesis of carboxymethylcellulose (CMC) from young coconut husk for edible film application. Young coconut husk was peeled the green part off, washed in 200 ppm sodium hypochlorite solution, cut, oven dried, milled and sieved with 60-mesh sieve, resulting in a yield of 7.82% of fresh young coconuts weight. Dried coconut flakes were composed of 51% of the rough powder (RP, average size of 480.27 microns) and 49% (by weight) of fine powder (FP, average size of 100.55 microns). Chemical compositions of the RP were 10.25% extractives, 45.77% polysaccharides, 35.32% lignin, 6.20% moisture and 2.46% ash (dry weight). The RP was boiled in 4-10% (w/v) NaOH. All of the extractives were eliminated. The higher the concentration of NaOH was used, the more lignin content was eliminated. The highest efficiency of delignification was achieved, when 10% NaOH was used. Further delignification process was done by using alternated treatment of 1% NaClO2 and 0.5% NaOH solutions (NaClO2/NaOH/NaClO2/NaOH/NaClO2). This resulted in 87.52% of delignification. Cellulose from young coconut husk was used to produce CMC, using 30% NaOH for alkalization reaction, leading to the highest degree of substitution at 1.32 and a yield of 167.35%. Various concentrations of CMC were used to prepared edible coating solutions based on the prototyped chitosan/gelatin formula. Apparent viscosities of the edible films ranged from 15-22 cP, water vapor permission ranged from 0.50×10-5-10.50×10-5 g·m/d·m2·Pa, OTR ranged from 9.17×10-7-43.70×10-7 g/d·m·Pa, tensile strength ranged from 1.63-2.91 MPa and percent elongation at break ranged from 57.09-79.21%.