Preservation of different fig cultivars (Ficus carica L.) under modified atmosphere packaging during cold storage.

BACKGROUND: The effect of modified atmosphere packaging (MAP) on the stability of 'Cuello Dama Blanco' (CDB), 'Cuello Dama Negro' (CDN) and 'San Antonio' (SA) figs during post-harvest cold storage was evaluated by using three different films with a diverse number of microperforations (diameter, ø = 100 µm): M10 (16 holes), M30 (five holes) and M50 (three holes). A macroperforated film was used as control (five holes, ø = 9 mm). Gas composition, weight loss, percentage disorder, microbial counts and physico-chemical parameters were monitored during cold storage for 21 days. Furthermore, sensory quality was also evaluated. RESULTS: MAP has allowed the extension of cold storage and distribution time for the three different cultivars of figs, minimising weight loss and delaying pathological disorders related to endosepsis, smut, and souring. Of the three cultivars, the M50 batch (one hole per 50 mm) showed the best efficiency in terms of physico-chemical quality and delay of post-harvest decay, although the M30 batch was also found to be suitable for delaying the post-harvest decay, especially for the CDB cultivar. CONCLUSION: MAP is a useful tool to extend the storability with optimal quality properties for CDN and SA during 21 days of cold storage and 14-17 days of cold storage for CDB.

Control of toxigenic Aspergillus spp. in dried figs by volatile organic compounds (VOCs) from antagonistic yeasts.

Aspergillus flavus and Aspergillus niger are fungi which can contaminate dried figs before and after harvest and consequently produce aflatoxins (AFs) and ochratoxin A (OTA). Many approaches have been applied to minimise the growth of these filamentous fungi, mainly involving the use of synthetic fungicides which are limited due to their negative impact on human health and the environment. In this context, biocontrol is a recent approach that needs to be explored. This study evaluated the potential of three volatile organic compounds (VOCs), octanoic acid (OA), 2-phenylethyl acetate (2PEA) and furfuryl acetate (FA), produced by Hanseniaspora uvarum and Hanseniaspora opuntiae yeasts on the growth, germination, gene expression and production of AFs and OTA by A. flavus M144 and A. niger M185 on dried fig-based agar and the incidence rates in dried figs. Two of the three VOCs evaluated (2PEA and FA) effectively controlled A. flavus M144 and A. niger M185 by using at least amounts of 50 µL (715 µL/L in the headspace) for FA and 100 µL (1430 µL/L in the headspace) for 2PEA in dried figs. One of the mode of actions of both compounds consists in early repressing the expression of genes involved in the biosynthesis of AFs (aflR) and OTA (pks) of A. flavus and A. niger, respectively. The results of this study support the application of 2PEA and FA at the early post-harvest stages of dried figs to control mycotoxin accumulation.

Evaluation of fungal hazards associated with dried fig processing.

The processing of dried figs in the industry involves a number of stages that present a significant risk of filamentous fungal infection of the fruit and subsequent mycotoxin contamination, due to the changes in temperature and water activity (aw) to which dried figs are exposed. In this study, the environmental conditions and the physicochemical parameters of dried figs at different processing stages were evaluated in 3 different industries, and were associated with fungal counts and the presence of toxigenic moulds and their mycotoxins. For this, dried figs at 5 relevant stages of industrial processing (curing, sizing, blanching, storage, and final product) in 3 industries located in Extremadura (Spain) were sampled. Changes in moisture content and aw of dried figs during processing were observed and they influenced the mycological quality of figs. Among the fungal genera, Aspergillus spp. predominated in most stages except blanching, where Penicillium spp. prevailed. About 10% of the dried fig samples were contaminated with aflatoxins (AFs) and 6% with ochratoxin A (OTA). Based on findings, longer drying times are necessary after blanching to reduce aw and to avoid the development of toxigenic moulds. In addition, all stages covering industry processing, final storage, and retailing of dried figs are advisable to be conducted at refrigeration conditions and controlled relative humidity to avoid mycotoxin production. The enumeration of AFs- and OTA- producing moulds by real-time PCR seems to be a good indicator for integration into prevention strategies to control filamentous fungal hazards and subsequent mycotoxin synthesis during the processing of dried figs.

Evaluation of the Physicochemical and Sensory Characteristics of Different Fig Cultivars for the Fresh Fruit Market.

Physicochemical and sensory properties of nine fig cultivars: 'San Antonio' (SA), 'Blanca Bétera' (BB), 'Brown Turkey' (BT), 'Tres Voltas L'Any' (TV), 'Banane' (BN), 'Cuello Dama Blanco' (CDB), 'Cuello Dama Negro' (CDN), 'Colar Elche' (CE), and 'De Rey' (DR), were compared at three different ripening stages. Weight, size, titratable acidity, pH, skin and flesh colours, firmness, maturation index (MI), and volatile compounds were determined in samples from two consecutive seasons, in addition to both descriptive and hedonic sensory analysis. The mechanical behaviour of figs determined by firmness analysis and colour changes in both skin and flesh was the most important trait for the discrimination of ripening stages. Notable differences among cultivars were found in most of the parameters studied, in particular the inter-cultivar differences highlighted for MI, pH, acidity, and skin colour analyses, followed by volatile compounds. Principal component analysis (PCA) indicated that MI, pH, colour parameters of flesh (h and L*), and terpenes were the best physicochemical indices to determine overall acceptability which is highly correlated with the sensory attributes flesh colour and fruit flavour. The results suggested that CDN and SA showed huge consumer acceptability among the fig cultivars studied.

Authentication of "Cereza del Jerte" sweet cherry varieties by free zone capillary electrophoresis (FZCE).

The purpose of this work was to develop a procedure based on protein analysis by free zone capillary electrophoresis (FZCE) that can be used as an alternative to other methods in the determination of sweet cherry varieties for the authentication of "Cereza del Jerte". Two autochthonous varieties of sweet cherry type "Picota", 'Ambrunés' and 'Pico Negro', and the foreign variety 'Sweetheart' were used in the study. Two protocols for extracting the methanol-soluble proteins were tested. On the basis of the results, direct evaporation with nitrogen of a methanol extract was included in the extraction protocol for routine analysis. This method was found to give excellent repeatability of the corrected migration time (CMT), and showed greater effectiveness in discriminating sweet cherry varieties than the SDS-PAGE technique. Three peaks found in the FZCE electropherograms were investigated as a basis for discriminating between varieties. In addition, the FZCE analysis of methanol-soluble proteins provides information about the physico-chemical parameters relevant to the sensorial quality of the sweet cherries.

Effect of the commercial ripening stage and postharvest storage on microbial and aroma changes of 'Ambrunés' sweet cherries.

The purpose of this work was to investigate the effect of the commercial ripening stage and postharvest storage on microbial and aroma changes of 'Ambrunés' sweet cherries. The microbial counts and volatile profile of sweet cherry batches automatically sanitized and classified in three commercial ripening stages were studied for five postharvest storages. The batches were also evaluated sensorially, and the correlations between volatile compounds and aroma quality were determined. The microbial counts provided evidence that 21 days of cold storage is near the maximum extension of 'Ambrunés' sweet cherry storage in maintaining the minimal microbial quality during their shelf-life period. Relevant changes associated with longer cold storages were found in different aroma constituents with a negative impact on flavor. These changes were more evident in less ripened sweet cherries, including a decrease of (E)-2-hexenal and 1-hexanol and an increase of 2-methyl-propanal and 2-methyl-butanal. These compounds could constitute a good tool to predict flavor quality in 'Ambrunés' sweet cherries during the cold-storage process.