Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop In vitro antifungal and anti-ochratoxigenic activities of Aloe vera gel against Aspergillus carbonarius isolated from grapes Islem Dammak a, ⁎ , Salma Lasram b , Zohra Hamdi b , Olfa Ben Moussa a , Khaoula Mkadmini Hammi c , Ines Trigui d , Hela Houissa b , Ahmed Mliki b , Mnasser Hassouna a a University of Carthage, Higher School of Food Industries of Tunisia (ESIAT), Research unit: “Bio-Preservation and Valorization of Agricultural Products UR13-AGRO 02”, 58 Alain Savary Street, El Khadhra City, 1003, Tunis, Tunisia b Laboratory of Molecular Physiology of Plants, Center of Biotechnology of Borj Cedria (CBBC), BP 901, 2050, Hammam-Lif, Tunisia c Laboratory of Aromatic and Medicinal Plant, Center of Biotechnology of Borj Cedria (CBBC), BP 901, 2050 Hammam-Lif, Tunisia d University of Sfax, National School of Engineers of Sfax, Valorisation, Analysis and Security of Food Laboratory, Soukra Road, 3038, Sfax, Tunisia ARTICLE INFO Keywords: Aloe vera gel Physico-chemical characteristics Aspergillus carbonarius Ochratoxin A ABSTRACT The basic objective of this study lies in determining the physico-chemical characteristics of Aloe vera gel in freshly harvested leaves, as well as evaluating its efficiency in terms of inhibiting the growth and ochratoxin A (OTA) production by Aspergillus carbonarius. The antifungal evaluation was performed by compound dissolution at the doses of 5, 10, 20, 30 and 50% in Czapek Yeast Agar medium (CYA). Our results revealed that Aloe vera gel did not display a pronounced antifungal effect on the growth of A. carbonarius. It rather showed a high anti- ochratoxigenic activity. Statistical analyses on growth rate of the fungus demonstrated that the main effect on mycelial growth was recorded at 50% of Aloe vera gel with an inhibition rate estimated at about 11.59%. At tested concentrations, Aloe vera gel could not totally inhibit the OTA production of fungus but only reduce it by 22.47–75.69% depending on concentration. However, this reduction was not positively correlated with the increase of the Aloe vera gel in the medium. The most important reduction on OTA synthesis was recorded at 20% of Aloe vera gel although no growth reduction was detected at this concentration. Overall, our results suggest that the concentration of Aloe vera gel should be between 20 and 30% to ensure an active inhibition of OTA production by A. carbonarius. This finding provides sound evidence that the use of Aloe vera gel as a biological pre-harvest treatment at the vineyard level is an effective, feasible and welcomed strategy. 1. Introduction Mycotoxins are toxic contaminants produced as secondary meta- bolites by several fungi growing on many agricultural commodities. Ochratoxins A (OTA) are potent mycotoxins produced by some strains of black aspergilli, among which we mention A. niger aggregate and A. carbonarius which are the main species producing this mycotoxin (Cabañes et al., 2002). These fungal metabolites have teratogenic, ne- phrotoxic, carcinogenic and immunosuppressive effects (Creppy et al., 1983; Krogh, 1992). OTA has been detected in a wide variety of food products as a result of fungal infection in crops at pre- and post-harvest in storage and in shipment under favorable environmental conditions. OTA was detected firstly in wine by Zimmerli and Dick, (1996). Since then, the presence of OTA in grapes and its derived products has been reported in a number of European and Mediterranean countries (Mateo et al., 2007). The European Union legislation authorities have introduced an OTA limit of 2 μg/L in grapes derived products such as wine, must and juice (European Commision, 2006). The frequency of occurrence of OTA production by different fungi species differs ac- cording to geographical regions. According to different surveys, grapes products from the Mediterranean regions of south Europe (Battilani et al., 2003; Bellí et al., 2004), and north Africa were the most con- taminated by OTA (Zimmerli and Dick, 1996). Aspergillus carbonarius is considered as the main ochratoxigenic fungi on grapes in Mediterranean countries (Battilani et al., 2006; Melki Ben Fredj et al., 2007; Lasram et al., 2007, 2012). Aspergillus carbonarius colonizes the berries in vineyards all along their growth, and especially at the maturation stage (Lasram et al., 2007). To solve this problem, chemical fungicide treatments have been used, but since the application of fungicides is becoming very restrictive, resorting to such natural substitutes, as the application of Aloe vera (Aloe barbadensis Miller) gel seems to provide a feasible solution to the problem (Valverde et al., https://doi.org/10.1016/j.indcrop.2018.07.023 Received 21 February 2018; Received in revised form 22 June 2018; Accepted 10 July 2018 ⁎ Corresponding author. E-mail address: islem.dammak.a@gmail.com (I. Dammak). Industrial Crops & Products 123 (2018) 416–423 0926-6690/ © 2018 Elsevier B.V. All rights reserved. T