Analysis of Biodegradable Films of Starch from Potato Waste

Abstract

Starch was extracted from potato wastes and its peels to prepare bio-degradable films using glycerol and sorbitol at various concentrations of 35%, 45% and 55 (w/w) of dry starch. The properties of films prepared with modification techniques (hydrothermal treatment (HTT) and acid-alcohol treatment (AAT)) were analyzed. Biodegradability test was done by incubating with amylolytic bacteria (Bacillus lichneformis and Streptococcus bovis) for 24 hours and fungi (Aspergillus niger and Rhizopus stolonifer) for 72 hours. All microbial species were isolated from soil except S. bovis which was from calf stool and identified by conventional methods. The properties of modified starches were significantly different from non-treated starches. Tensile strength (10 N/m2) and elongation (9.47%) were significantly (p<0.05) superior in HTT starch films whereas solubility (25.8%) was superior in AAT starch films.  Elongation (8.91%) and solubility (29.98%) were significantly (p<0.05) superior in 35% and 55% glycerol used films respectively but tensile strength (13.02 N/m2) was superior in 35% sorbitol used films. WVTR (999 g/m2/d) was higher at 91% RH in 55% glycerol used films. Micro-organisms used showed a significant effect (p<0.05) on biodegradation of starch based films. Highest degradation was observed by B. lichneformis i.e, 57.85% while A. niger had minimum of 25.13%. Films prepared with 35% glycerol was significantly (P<0.05) degraded by B. lichneformis i.e, 78.86%. Films prepared by using glycerol with acid alcohol treatment was significantly (P<0.05) degraded by S. bovis (55.57%). Although the starch of same variety of potato waste was not studied, results of the study suggest possibility of preparation of starch based bio degradable films potato waste and its peels by using glycerol and sorbitol.