DEVELOPMENT AND CHARACTERIZATION OF BIODEGRADABLE FILMS BASED ON PERSIMMON (Diospyros kaki L. CV. RAMA FORTE) INCORPORATED WITH GLYCEROL AND PECTIN

Puree persimmon films (Diospyros kaki L. cv. Rama Forte) incorporated with glycerol and pectin by casting technique were formulated using a Plackett-Burman design and characterized. The puree showed high carbohydrate content, comprising 0.75 mg.100g-1 of maltohexaose and 15.53 and 1.87 g.100g-1 of monosaccharides and fiber, respectively. Temperature, glycerol and puree concentration were the variables that most positively influenced the films’ tensile strength (0.75 - 1.30MPa), elongation at rupture (17.69 - 26.02 %) and Young's modulus (3.34 - 10.94 MPa). Samples presented high water solubility (68.80 - 80.86 %) and vapor permeability [5.77 - 6.63 g.mm.(hm²kPa)-1]. Scanning electron microscopy showed smooth surfaces and good plasticizer dispersion. Fourier-transform infrared spectroscopy showed similar absorption peaks among samples, suggesting different formulations did not greatly affect their chemical structure. The films presented similar curves of thermogravimetric analysis with important steps of degradation: 210 and 335ºC. The films exhibited a vivid orange color and interesting antimicrobial potential against S. aureus and E. coli. Persimmon puree proved to be a suitable and promising raw material for the formulation of edible and biodegradable films by casting technique, and, as far as we know, this is the first study reporting films based on persimmon puree. We highlight that the films were produced from whole persimmon fruits, which means there was no residue generated in this process, demonstrating their innovative potential as a green product. The production of films from fruits and vegetables should be encouraged in order to reduce post-harvest loss and the use of non-biodegradable polymers. So-called “bioplastics” from fruits are thus considered added-value products, fitting them in the context of circular economy.