To cite this article: Putri, R. D. A, Setiawan, A. & Anggraini, P. D. (2018). Physical properties of edible sorgum starch film added with carboxymethyl cellulose. J. Phys. Sci., 29(Supp. 2), 185–194, https://doi.org/10.21315/jps2018.29.s2.14
Edible films have been widely used in food packaging. One of the basic materials of these edible films is starch. One potential source of starch is sorghum which contains 72% starch. However, generally starch-based edible film which contains amylopectin has some weaknesses such as being fragile, easily broken and less flexible. Carboxymethyl cellulose (CMC), a cellulose derivative product, is expected to improve the mechanical properties of starch-based edible film. The objective of this work is to study the physical properties of sorgum flour film and the effect of CMC as an additive in the characteristic of edible film biopolymers that produce sorghum flour. The study was started with the production of sorghum starch, and then synthesised with the addition of CMC starch (0%, 5%, 10%, 15%, 20% and 25% w/w), and finally the mechanical characterisation and Fourier transform infrared (FTIR) analysis. The tensile test results showed that the addition of CMC has affected the tensile strength, elongation and elasticity. The lowest level of tensile strength was at 7.742 MPa at 0% of CMC concentration and the highest level was at 29.988 MPa with CMC concentration of 10%. The addition of CMC to the film also affected the elongation properties of the sorghum film. The lowest level of elongation of the film was 14% at 0% of CMC concentration and the highest one was 65% at 25% of CMC concentration. The addition of CMC also affected the elasticity of the sorghum film. The lowest elasticity level was 3.1 mm at 0% of CMC concentration and the highest level one was 5.2 mm at 25% of CMC concentration. Whereas, the FTIR analysis results showed that the addition of CMC did not form any new group, which means that the synthesis process occurred only physically.