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Impact of water management and geographic location on the physicochemical traits and fungal population of ‘Calabacita’ dried figs in Extremadura (Spain)

2022; Elsevier BV; Volume: 308; Linguagem: Inglês

10.1016/j.scienta.2022.111543

1879-1018

Ana Isabel Galván, Maria de Guı́a Córdoba, Santiago Ruiz‐Moyano, M. López‐Corrales, Emilio Aranda, Alicia Rodríguez, Manuel Joaquín Serradilla,

Mycorrhizal Fungi and Plant Interactions

The traditional process of sun-drying figs involves a high risk of toxigenic mold contamination and, as a consequence, potential mycotoxin occurrence. In this study, the influence of the environmental conditions in the three main production areas of 'Calabacita' dried figs in Extremadura (Spain), more precisely Almoharín, Guadajira, and Guareña, on physicochemical traits and microbiological quality was evaluated. Simultaneously, the impact of water management, irrigated and rainfed conditions, in the Almoharín area was also determined. For this purpose, dried fig samples were collected in two consecutive seasons (2018 and 2019) at different drying steps, harvesting from the ground and after final drying under greenhouse conditions until the final moisture content was reached. All physicochemical parameters were significantly influenced by geographic location whereas water management had only a significant impact on firmness, total soluble solids and fruit size. Changes in moisture content and aw of dried figs from different geographic locations as well as water management modified yeast counts, while mold counts did not show significant changes. However, the mold population was complex, with 40 species identified, mainly belonging to Penicillium spp. (29.4%), Aspergillus spp. (24.5%), Cladosporium spp. (18.9%) and Alternaria spp. (17.3%). The occurrence of these mold species was strongly influenced by geographic location while the influence of water management was minimal. Furthermore, a substantial co-occurrence of samples contaminated with aflatoxin- and ochratoxin A-producing Aspergillus species was found. Of the total samples of dried figs analysed, 10.8% were contaminated with aflatoxins ranging from 0.1 to >70 ppb and 12.5% with ochratoxin A in the range from 10 to >70 ppb. The edaphoclimatic conditions specific to each geographic location set the physicochemical and microbiological quality of dried figs in Extremadura. In contrast, rainfed conditions had a limited impact beyond fruit size and higher level of AFs-producing mold under water stress. These findings are crucial to minimize the risks associated with the occurrence of toxigenic molds on dried figs.