Please cite this article in press as: Kra´ sniewska, K., et al., The application of pullulan coating enriched with extracts from Bergenia crassifolia to control the growth of food microorganisms and improve the quality of peppers and apples. Food Bioprod Process (2014), http://dx.doi.org/10.1016/j.fbp.2014.06.001 ARTICLE IN PRESS FBP-505; No. of Pages 12 food and bioproducts processing x x x ( 2 0 1 4 ) xxx–xxx Contents lists available at ScienceDirect Food and Bioproducts Processing j ourna l ho me page: www.elsevier.com/locate/fbp The application of pullulan coating enriched with extracts from Bergenia crassifolia to control the growth of food microorganisms and improve the quality of peppers and apples Karolina Kra ´ sniewska a , Malgorzata Gniewosz a,∗ , Alicja Synowiec a , Jaroslaw L. Przybyl b , Katarzyna B˛ aczek b , Zenon W˛ eglarz b a Department of Biotechnology, Microbiology and Food Evaluation, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159c, 02-776 Warsaw, Poland b Department of Vegetable and Medicinal Plants, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland a b s t r a c t The objective of this study was to investigate the composition of polyphenolic compounds of water and ethanol extracts from leather bergenia leaves (LBL) and to determine the antimicrobial properties of pullulan coating enriched with these extracts. The result showed that both extracts consisted mainly of flavonols and phenolic acids. The antimicrobial activity of pullulan coating solution was determined at different concentrations: 0.4, 1, 2, 5, 10, 20% (w/v) of extracts. The incorporation of LBL extracts showed antimicrobial activities of the films against both Gram- positive and Gram-negative bacteria and molds. Pullulan films incorporated with 20% of LBL extracts showed the strongest antimicrobial activity. In the next part of the study pullulan coating solution with a 20% concentration of water LBL extract was chosen and used as coating on pepper and apple surfaces. Non-coated samples of food were also used as controls. Samples coated with the antimicrobial solutions showed advantages in reducing microbial growth by 1 log CFU/g as compared to the control samples. Physico-chemical and organoleptic observations were also evaluated after storage. The application of the pullulan film enabled an extension of the storage time of the peppers and apples as a result of reduced weight losses and helped to maintain their hardness. © 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Keywords: Pullulan coating; Bergenia extracts; Antimicrobial activity; shelf-life; Pepper and apple; SEM 1. Introduction Fruits and vegetables are essential components of the human diet and there is considerable evidence concerning the health and nutritional benefits associated with their consumption. Apples and sweet red peppers were selected as model systems for the application of coating formulations for several reasons. They are produced in large quantities all over the world and are available on the market throughout the year. Furthermore, they lose weight easily during storage and are perishable; this ∗ Corresponding author. Tel.: +48 22 59 37 653. E-mail address: malgorzata gniewosz@sggw.pl (M. Gniewosz). is the main cause of their shelf-life termination. Peppers and apples are well known for their crispy flesh, sweet and juicy variety, as well as for their nutritious content. Fresh peppers and apples are often eaten raw (Kissinger et al., 2005; Mehyar et al., 2011). Among different degraded quality characteristics, the main problems limiting the shelf-life of peppers occur as a result of shriveling and decay development on the cut surface, as well as degreening of the vegetable (Kissinger et al., 2005). In apples unprofitable fruit changes are observed during long- term storage. Damaged apple skin initially loses its shine, and http://dx.doi.org/10.1016/j.fbp.2014.06.001 0960-3085/© 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.