The antimicrobial activity of pullulan film incorporated with meadowsweet flower extracts (Filipendulae ulmariae flos) on postharvest quality of apples

This study examined the antimicrobial activity of pullulan films with incorporated meadowsweet flower extracts (EMFs) and the effectiveness of these coatings in the prolonging of apple stability in various storage conditions. Pullulan was obtained from a batch culture of white mutant Aureobasidium pullulans B-1. The content of phenolic components in two extracts-water-ethanol (weEMF) and ethanol one (eEMF)-was compared using the HPLC method. Compared to eEMF, a significantly higher content was noted of phenolic acids and flavonoids in weEMF and its increased activity in inhibiting microorganism growth. Pullulan films with incorporated EMFs were obtained from the solutions to which they were added in concentrations of 3, 6, 9, 12 and 15%. These films were stable and homogenous, and to a higher degree inhibited the growth of tested bacteria than fungi. Apples of the Jonagored variety were coated with a pullulan coating containing 12% EMF. The pullulan coating with EMFs evened and unified the surface of apple skins. Pullulan coating with weEMF more effectively inhibited the growth of natural mesophilic microflora, the amount of which decreased by two logarithmic cycles at the end of storage. EMF addition to the coating significantly limited the growth of the Rhizopus arrhizus mold inoculated to the apples. EMF addition to pullulan coating did not affect color changes nor did apples loss weight during their storage. Pullulan coatings with incorporated EMFs may protect apple quality during their storage and turnover in various temperatures and time conditions. (C) 2013 Elsevier Ltd. All rights reserved.