Nafissatou Diop Ndiaye

Mangifera indica species presents a wide varietal diversity in terms of fruit size and morphology and also of physicochemical and organoleptic properties of the pulp. In Senegal, in addition to the well-known export varieties, such as ‘Kent’, local varieties have been little studied particularly during ripening. This study aims to propose prediction models integrating variables deduced from varietal characteristics. Five mango varieties (‘Diourou’, ‘Papaye’, ‘Sierraleone’, ‘Boukodiekhal’ and ‘Sewe’) endemic to Senegal were characterized at harvest and followed during ripening storage. Caliber parameters were determined at green-mature stage as well as storage (25 °C) weight losses. Considering the ‘ripening storage time’ (R_ST) variable as ripeness level index, intra-varietal prediction models were built by multi-linear regression (R² = 0.98) using pulp pH, soluble solid content (SSC) and Hue angle. In addition to these physicochemical parameters, variety-specific size, shape and weight loss parameters, were additional variables in multi-linear models (R² = 0.97) for multi-varietal prediction of R_ST. Results showed that storage time, which was the most influential factor on the pH, SSC and Hue, can be used as a response for varietal prediction of mango ripening. As a decision support tool, theses statistical models, validated on two seasons, will contribute to reduce post-harvest losses and enhance mango value chain through a better ripening process monitoring.

In Senegal, traditional baobab (Adansonia digitata L.) fruit nectar (T-BFN) is the most popular drink from baobab fruit pulp and its consumption helps to fight poverty, malnutrition and generate income along the Senegalese value chain of non-timbered forest products. However, for a better competitiveness in the local market, traditional baobab fruit nectar must be microbiologically stable with an attractive visual aspect. The aim of this study is to evaluate the microbial quality during storage, and the impact of some treatments like homogenization on the visual appearance of traditional baobab fruit nectar processed in Senegal. The microbial shelf-life of pasteurized traditional baobab fruit nectar and the effect of homogenization at 0, 5, 8, 12, 13 and 14 MPa on the stability of visual appearance during storage have been studied. Pasteurized traditional baobab fruit nectar could be stored up to 190 days at 4°C without microbial spoilage. Homogenization at 14MPa stabilized the visual appearance of traditional baobab fruit nectar without sedimentation of the pulp or clarification for days at 4°C. In combination with pasteurization, homogenization may be addressed as an effective tool to prevent pulp sedimentation in traditional bottled baobab fruit nectar. Key words: Baobab fruit nectar, microbial quality, visual appearance, storage, homogenization pressure, pulp sedimentation. In Senegal, traditional baobab (Adansonia digitata L.) fruit nectar (T-BFN) is the most popular drink from baobab fruit pulp and its consumption helps to fight poverty, malnutrition and generate income along the Senegalese value chain of non-timbered forest products. However, for a better competitiveness in the local market, traditional baobab fruit nectar must be microbiologically stable with an attractive visual aspect. The aim of this study is to evaluate the microbial quality during storage, and the impact of some treatments like homogenization on the visual appearance of traditional baobab fruit nectar processed in Senegal. The microbial shelf-life of pasteurized traditional baobab fruit nectar and the effect of homogenization at 0, 5, 8, 12, 13 and 14 MPa on the stability of visual appearance during storage have been studied. Pasteurized traditional baobab fruit nectar could be stored up to 190 days at 4°C without microbial spoilage. Homogenization at 14MPa stabilized the visual appearance of traditional baobab fruit nectar without sedimentation of the pulp or clarification for days at 4°C. In combination with pasteurization, homogenization may be addressed as an effective tool to prevent pulp sedimentation in traditional bottled baobab fruit nectar. Key words: Baobab fruit nectar, microbial quality, visual appearance, storage, homogenization pressure, pulp sedimentation.

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.

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.

In Senegal, Detarium senegalense J.F. Gmel. (ditax in Wolof) is one of the most important ¶important forest fruit species. ¶However, exploitation of the edible fruit is based on local people’s knowledge. Only trees whose fruits are consumed by animals are exploited. ¶To identify them, a chemical comparison of edible and toxic forms was done in order to highlight differences between both forms. Dichloromethane leaf extracts from toxic and edible trees were analyzed by gas chromatography. Phenolic profile and volatile compounds from fruits extracts were studied respectively by High Performance Liquid Chromatography-mass spectrometry (HPLC-MS) and Gas Chromatography Mass Spectrometry (GC-MS). Cytotoxicity effect of fruits extracts was evaluated on murine macrophage cells J774 A1. GC-analysis of dichloromethane leaf extracts revealed the presence of lupenone and lupeol only in toxic extracts. 6’-O-galloyl-epiheterodendrin and isovaleronitrile were detected in toxic pulp. However, no cytotoxic effect was found in our conditions. This study has given the opportunity to identify within the same species, compounds which could differentiate both edible and toxic forms. Nevertheless further studies are needed to better understand which compounds are responsible for toxicity in the toxic form. Key words: Ditax, Detarium senegalense, toxicity, lupeol, lupenone, cyanogenic glycoside, isovaleronitrile.