Mady Cisse

Thermal degradation kinetics of anthocyanins from blood orange, blackberry, and roselle using the Arrhenius, Eyring, and Ball models.

Anthocyanin stability was assessed over temperatures ranging from 30 to 90 degrees C for seven products: blood orange juice [Citrus sinensis (L.) Osbeck]; two tropical highland blackberry juices (Rubus adenotrichus Schlech.), one with high content and the other with low content of suspended insoluble solids (SIS); and four roselle extracts (Hibiscus sabdariffa L.). The blackberry juice showed the highest content of anthocyanins with 1.2 g/L (two times less in the roselle extracts and 12 times less in the blood orange juice). The rate constant for anthocyanin degradation and isothermal kinetic parameters were calculated according to three models: Arrhenius, Eyring, and Ball. Anthocyanins in blood orange juice presented the highest rate constant for degradation, followed by the blackberry juices and roselle extracts. Values of activation energies were 66 and 37 kJ/mol, respectively, for blood orange and blackberry and 47-61 kJ/mol for roselle extracts. For the blackberry juices, a high SIS content provided only slight protection for the anthocyanins. The increasing content of dissolved oxygen, from 0.5 to 8.5 g/L, did not significantly increase the rate constant. For both isothermal and nonisothermal treatments, all three models accurately predicted anthocyanin losses from different food matrices.

Impact of the extraction procedure on the kinetics of anthocyanin and colour degradation of roselle extracts during storage

BACKGROUND The stability of anthocyanins and colour of aqueous extracts from roselle (Hibiscus sabdariffa L.) was investigated during storage at 4-45 °C. The effect of the extraction procedure (cold or hot extraction with or without pasteurisation) on the kinetic behaviour was determined. RESULTS Data analysis showed first-order kinetics for the evolution of anthocyanin content, colour density, colour strength and browning index. Three models (Arrhenius, Eyring and Ball) were used to represent the temperature dependence of the reaction rates. The three models allowed the prediction of colour modifications according to the storage temperature over 6 months. Activation energies ranged from 22 to 26 kJ mol(-1) for anthocyanin degradation and from 18 to 34 kJ mol(-1) for colour parameter modification. The degradation rate during storage depended on the extraction procedure. When heated, the extracts were clearly less stable. Their colour changed faster during storage especially when hot water and pasteurisation were used. CONCLUSION Although the anthocyanin content and initial colour were not modified, the extraction conditions, especially temperature, greatly affected the stability of the extracts during storage. Further studies are needed to understand the mechanisms involved.

Saba senegalensis : Key Features and Uses

Native of West Africa, Saba senegalensis belongs to the family of Apocynaceae, and is a wild plant that is mainly exploited in the diet. It grows mainly along riverbanks, in wooded savannah areas in humid areas, in gallery forests and in rocky ravines and hills. Saba senegalensis is a large woody liana with white latex, dark gray bark, can reach more than 40 m high and a trunk that can measure up to 47 cm in diameter. The fruit is a globose shell, 7 to 10 cm long, 6 to 8 cm wide. The leaves are opposite, elliptical, dark green in color, about 8 to 15 cm long and 4 to 6 cm wide. This fruit is characterized by its richness in antioxidant molecules especially vitamin C (480 mg/100 g) and total polyphenols (945.83 mg/100 g). The fruit contents 41.43 until 80% water with a low pH (2.24). In Senegal, the fruit is eaten as it or transformed into puree, nectar, syrup, canned etc. It is a plant that has enormous therapeutic virtues, from the fruit to the roots through the leaves, bark, and latex. Despite its high nutritional potential, its many therapeutic virtues and its economic potential, Saba senegalensis remains under-exploited. Further researches on the nutritional and therapeutic properties deserve to be conducted.

Nutritional composition of Meristotheca senegalense (Rhodophyta): A new nutrient source

Macroalgae are used in diverse global regions. Meristotheca senegalense J. Feldmann, a macroalga species found in a Senegalese bay, was the subject of this study focusing on the chemical and mineral composition. The present study was done in order to evaluate the potential of this macroalgal resource for biomass development and contribution to the economy in Senegal. The results of this study showed that M. senegalense J. Feldmann was relatively a good source of nutrients including fiber (6.67 ± 0.7%) and protein (6.37 ± 0.8%). Mineral analysis also showed significant concentrations of magnesium (216.87 ±12.9 mg/100 g), calcium (81.6 ± 17.5 mg/100 g), iodine (31.16 ± 1.5 mg/kg) and iron (28.13 ± 2.15 mg/100 g). However, zinc and copper 3.31 ± 0.26 and 2.43 ± 0.13 mg/100 g respectively were found at relatively low concentrations. Interestingly, the vitamin B12 content was significant with a content of 20 ± 1.0 mg/kg, potentially allowing for the use of the alga as a supplemental. The nutrient concentrations reported for M. senegalense J. Feldmann suggests that its cultivation and harvest can be a source of diversification in the activities of fishermen. In terms of food consumption, the results also showed that the red alga used in this study can be added to human diets as supplementation and might also be F Key words: Meristotheca senegalense, nutrient composition, macroalgae, supplementation, food diversification.

Formulation of Infant Food Based on Local Cereals: Stability and Effectson Cognitive Development

Our goal was to develop nutritious; accessible and stable infants flour which would improve cognitive and behavior abilities for African children. Five formulations (F1 to F5) based on local cereals from Senegal were manufactured according to FAO/WHO nutritional requirements and composed to reach equal energetic value (400 Kcal/Kg). Flours formulation stability was studied by storage at 20°C and5 relative humidities (0%to 95%) for 10 months. Flour dextrose equivalent; color and fat composition were followed and all formulated flours showed very good stability for a storage relative humidity below 75%. During in vivo nutritional tests; a comparative weight study between mice fed with standard nutritive flour (control); and those fed with F1 to F5 formulations showed a similar slope of weight gain even if adaptation time to new feed initially retard mice growth. F2 and F3 showed the highest weight deficiency compared to the control. Y and Morris Tests; used to characterize the behavior showed that F3; F4 and F5 formulations significantly increased psychomotor activity compared to the control. Long term memory was not significantly different between all formulations; except for F5 which showed a clear improvement. F2 formulation composed of corn was the least efficient for working memory due to its low proteins quality. The low number of triplets can slightly affect the F2 alternation percent; even if this effect was not observed for the control. The other formulations gave results close to the control food. F4 and F5 formulations showed good nutritional qualities; F4; enriched with vitamins and minerals; as well as F5 enriched with fish oil gave very good results on all growth and comportment parameters. They might be effective for better cognitive and somatic development of children.