Biopolymer films to control fusarium dry rot and their application to preserve potato tubers

Films were cast using sodium alginate (NaAlg), high molecular weight (HMW) chitosan, and low molecular weight (LMW) chitosan as film forming biopolymers. Fludioxonil (Fl) at 1% concentration was used as fungicide. Thermal stability, mechanical, and water sorption properties of the films were examined. The effects of films on the Fusarium solani colony radial growth were evaluated in vitro and in potato tubers. Results showed that chitosan films were more thermally stable and less hydrophilic than alginate films. Addition of fluodioxonil to the films significantly reduced the film strength and increased the elongation at break as well as the film stiffness. In vitro studies showed that when fludioxonil was added to the formulation, NaAlg and Chitosan-LMW films had significantly higher antifungal activity (Fungistatic index = 56%) than Chitosan-HMW films (Fungistatic index = 50%). In vivo studies showed that Chitosan-LMW-1% Fl films delay the mycelial growth of F. solani in tubers kept at 25 degrees C for 2 weeks. (C) 2016 Wiley Periodicals, Inc.