Preservation of mango quality by using functional chitosan- lactoperoxidase systems coatings Mohamed Cissé a, b, *, Jessica Polidori a , Didier Montet a , Gérard Loiseau a , Marie Noëlle Ducamp-Collin a a CIRAD, UMR Qualisud, 73 rue Jean François Breton, 34398 Montpellier Cedex 5, France b University Peleforo Gon Coulibaly Korhogo, Cote d’Ivoire A R T I C L E I N F O Article history: Received 20 June 2014 Received in revised form 25 October 2014 Accepted 3 November 2014 Keywords: Chitosan Lactoperoxidase system Edible coatings Mango A B S T R A C T Influence of chitosan coating with or without the active antimicrobial lactoperoxidase system was studied on postharvest mangoes. Mangoes were treated with three concentrations of chitosan (0.5; 1; 1.5%) containing or not lactoperoxidase with or without iodine as a second electron donor. Coatings containing 1 and 1.5% chitosan incorporated with lactoperoxidase system efficiently inhibited fungal proliferation and delayed mango ripening. Iodine did not influence antifungal activity. Ripening parameters (firmness, respiration, weight loss and color) were not influenced by the lactoperoxidase system, but were more influenced by chitosan concentration. Chitosan coating alone reduced weight loss, and delayed the decline in firmness and respiration rate. It exhibited a beneficial effect on the contents of total soluble solids (TSS), ascorbic acid, total acidity (TA) and pH. ã 2014 Elsevier B.V. All rights reserved. 1. Introduction Developing countries experience significant postharvest losses of fruit and vegetables, and among these agricultural products, mango is a dominant tropical fruit variety (FAO, 2003). However, mangoes face problems in storage due to various diseases caused by fungi and bacteria. The control of these diseases has become difficult because of strain resistance to fungicides and increasingly rigorous regulations. These regulations on the use of fungicide have reduced the ability to develop control strategies based on chemicals (Johnson and Sangchote, 1994). An alternative to this problem could be the use of natural compounds that have a broad antimicrobial spectrum. The lactoperoxidase system (LPOS) has been described as an excellent system for fighting pathogenic microorganisms as it has a broad antimicrobial spectrum. This enzyme system has shown a bactericidal effect on Gram-negative bacteria and a bacteriostatic effect on Gram-positive bacteria (Seacheol et al., 2005). In addition, it has antifungal (Jacob et al., 2000) and antiviral activity (Pakkanen and Aalto, 1997; Seifu et al., 2005). This system generates intermediate antimicrobial products such as hypothiocyanite (OSCN  ) and hypothiocyanate acid (HOSCN). These highly reactive products inhibit microorganisms by oxidation of the sulfhydryl groups of microbial enzymes (Martínez-Camacho et al., 2010). Presence of iodine in addition to thiocyanate increases the fungicidal and bactericidal effect against microbes such as Candida albicans,Escherichia coli and Staphylococcus aureus (Bosch et al., 2000). LPOS incorporated into matrix polymers by immobilization, absorption, or trapping has been operating in the pharmaceutical and food areas. The effectiveness of incorporation of the LPOS into whey proteins (Min et al., 2005; Min and Krochta, 2005) and alginate films (Fatih et al., 2009) has been demonstrated. Chitosan has multiple biological and chemical properties. Amino and hydroxyl groups of the linear polyglucosamine chain are very reactive, and conse- quently it is amenable to chemical modification. Dissolved in an acid solution, chitosan has a high positive charge on NH3 + groups which can form an aggregate with polyanions. This characteristic provides excellent ionic properties to chitosan gels which give them remarkable affinity to proteins. In addition, chitosan has antimicrobial properties and can protect fruit against fungal deterioration (Atia et al., 2005; Photchanachai et al., 2006). Chitosan could be used to stabilize LPOS antimicrobial activity for a long time, and it may also delay the ripening of fruit. The objective of this study, therefore was to enhance the effectiveness of LPOS linked to chitosan and thereby extend the postharvest preservation of mangoes. * Corresponding author at: BP 1328 Korhogo, Cote d’Ivoire. Tel.: +33 4 67615498/225 07082215; fax: +33 4 67615515. E-mail address: cismorad@yahoo.fr (M. Cissé). http://dx.doi.org/10.1016/j.postharvbio.2014.11.003 0925-5214/ ã 2014 Elsevier B.V. All rights reserved. Postharvest Biology and Technology 101 (2015) 10–14 Contents lists available at ScienceDirect Postharvest Biology and Technology journal home page: www.elsevier.com/locat e/postharvbio