Mady Cissé

Tannins can interact with anthocyanins to form complexes that stabilize color and protect anthocyanins from degradation. Thus, this work proposes to study the effect of the tannins of bark of the fruit of Saba Senegalensis and Combretum Micranthum on the stability of the anthocyanins of drink based on red calyxes of hibiscus obtained by co-maceration. The anthocyanin concentration was determined by the pH-differential method. The red color degradation index is determined based on the CIELAB (International Commission of Lighting) color system (L*, a*, b* and L*). R and Minitab 18 software were used for data processing. Monitoring of the residual anthocyanin content and the intensity of the red color was carried out over eight weeks. The results showed that Saba Senegalensis tannins interact better with anthocyanins. After eight weeks of storage at 4°C, 89.36 % of the anthocyanins are preserved with the Saba S tannins against 83.62 % for the control batches and 80.38 % for the Combretum tannins. Storage at 37°C for eight weeks reveals very high loss rates, 14.86 % of the anthocyanins are preserved (Saba tannins) against 3.38 % for the control and 1.84 % with the Combretum tannins. Moreover, the intensity of the red color is better preserved at 4 °C and 37 °C with the tannins of Saba Senegalensis.

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.

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.

One of the challenges of studying food consumption behavior is to identify the drivers of choice for a food product. This is particularly important to design and develop new foods for which no previous information is available. Hibiscus sabdariffa L. (Bissap) is an herbaceous plant and an important source of vitamins, minerals, and bioactive compounds, which confer a number of potential health benefits to derived products. The consumption of Bissap in beverage form is widespread in Africa and Asia, but not yet in Europe. Therefore, this study aimed to identify the main drivers of consumer acceptance of a traditional African beverage made from Bissap to which they had not been previously exposed. First, three focus groups (n = 22) were performed in Portugal to characterize the sensory profile of four Bissap beverages, to reveal perceptions and attitudes towards Bissap beverages, and to identify potential choice attributes. Subsequently, a full-profile conjoint analysis (n = 99) was performed, where consumers evaluated 37 Bissap beverage profiles, aiming to estimate choice attribute importance and to identify relevant market segments. Focus group findings showed that consumers would choose Bissap because they perceived as a healthy choice, and due to its novelty. The conjoint study showed an ideal profile for a Bissap beverage costing €0.99/L, price sensitive, body concerned, packaging attracted, and demanding, highlighting the most influential choice attributes: price, calories, and packaging. Findings provide useful guidance for new product development of an African product in the European lifestyle. Results might be useful from a nutraceutical point of view and to the food/beverages industry.