Dynamics of bacterial and fungal communities of mango: From the tree to ready-to-Eat products.

Processing, such as fresh cutting and drying, is essential to enhance profitability; therefore, to limit waste and reduce losses in fruit production such as mangoes. Metabarcoding and microbial enumeration methods were utilized to explore the structure of mango microbiota, as well as their evolution after processing. Two mango ripening stages of cv. Cogshall were selected and processed into fresh-cut pieces or dried slices. Microbiological and physicochemical parameters were monitored during product storage, in order to assess the dynamics of quantitative and qualitative variations of the microbial flora. Proteobacteria was the dominant bacterial phylum of the mango surface and accounted for 73.16%, followed by Actinobacteria (10.16%), Bacteroidetes (7.82%) and Firmicutes (6.68%). Aureobasidium and Cladosporium were the only two genera shared between all types of samples (peel surface, dried slices and mango fresh-cut). However, the bacterial genera Lactobacillus and Pantoea were the most abundant in fresh-cut mango after 14 days of storage. Ascomycota was the dominant fungal phylum in the mango surface and accounted for 90.76% of the total number of detected sequences, followed by Basidiomycota (9.21%). In total, 866 microbial genera were associated with mango surface (562 bacterial and 304 fungal). Among detected yeast genera, Saccharomyces, Candida and Malassezia prevailed in mango flesh and were replaced by Wickerhamomyces after 14 days of storage. Alpha and beta diversity analyzes revealed differences in fungal and bacterial communities on fruit peel, in fresh-cut, dried slices, and during conservation (fresh-cut and dried slices). Mango processing (washing, peeling, cutting and drying) reduced the richness and the microbial diversity (bacterial and fungal) associated to the fruit, and drying limits the development of cultivable microorganisms during storage in comparison to fresh-cuts mangoes.

Impact of Special Drying Schemes on Color Stability of Mangoes with Different Maturity Degrees.

A previous study demonstrated that the color of 4 mm mango slices is altered very slightly by drying for 5 h at 60 °C, 30% RH and 1 m/s. The objectives of this complementary study were to determine the impact of various drying procedures encountered in the drying units on color alterations of sulfite-free mango slices from heterogeneous raw material due to variable maturity degrees of mangoes. Drying procedures with various temperature/humidity/duration combinations were performed to analyze their effects on the color of natural dried mangoes according to the degree of fruit maturity. They were dried at an air speed of 1.0 m/s for 5 h according to 3 schemes: standard drying (SD) at 60 °C and 30% RH; wet drying (WD) for 1 h at 60 °C and 60% RH, followed by 4 h SD; and finally, hot drying (HD) for 4 h SD, followed by 1 h at 80 °C and 30% RH. The color of the mango slices was analyzed before and after drying. SD preserves the color of fresh mangoes very well, whatever their maturity stage. A relatively slow drying onset corresponding to WD has a highly adverse impact, which becomes greater as the degree of maturity increases. There is already significant browning on mangoes with near-optimum quality (L* = 75; H* = 92). Applying high temperature at the end of the drying procedure (HD) for 20% of the time has a more limited adverse impact with immature mangoes that are the most sensitive. Linear regressions were assessed to represent the relationships of color differences between drying schemes according to mango maturity degrees. These statistical models showed a significant increase in color degradation in the case of WD and a decrease in color differences in the case of HD with the advance in fruit maturity.

Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes.

The purpose of this study was to evaluate the impact of the harvest stage, ripening conditions and maturity on color changes of cv. 'Cogshall' and cv. 'Kent' variety mangoes during drying. A total of four harvests were undertaken, and the fruits were ripened at 20 and 35 °C for five different ripening times at each temperature. At each ripening time, mangoes were dried at 60 °C/30% RH/1.5 m/s for 5 h. A wide physico-chemical and color variability of fresh and dry pulp was created. The relationships according to the L*, H* and C* coordinates were established using mixed covariance regression models in relation to the above pre- and postharvest (preprocess) parameters. According to the L* coordinate results, browning during drying was not affected by the preprocess parameters. However, dried slices from mangoes ripened at 35 °C exhibited better retention of the initial chroma, and had a greater decrease in hue than dried slices from mangoes ripened at 20 °C. However, fresh mango color, successfully managed by the pre- and postharvest conditions, had more impact on dried mango color than the studied parameters. The preprocess parameters were effective levers for improving fresh mango color, and consequently dried mango color.