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.

Extraction of glucomannan from crude porang flour by acid hydrolysis and ethanol precipitation was studied. Effects of acid concentration, temperatures and time were investigated, kinetics model of the process was developed and the parameters were evaluated based on experimental data. New data on yield and purity of glucomannan under various conditions were obtained.

Article original The African baobab tree (Adansonia digitata L.): principal characteristics and uses. Abstract-Introduction. Very characteristic of Sahelian areas, Adansonia digitata L. belongs to the Bombacaceae family. Essentially exploited in a spontaneous state for its fruits or its leaves, the baobab plays an important role in the local traditional cultures. The plant. This very big tree is clearly distinguishable from the other Adansonia species endemic in Madagascar and Australia, mainly by its very large trunk (up to 10 m in diameter), its pendular flowers and its rounded crown. It produces (150 to 300) g dry berries with a woody epicarp, most of the time ovoid, called "monkey bread". These fruits contain many seeds in a whitish and floury pulp. The compounded leaves consist of five to seven digitate leaflets. The baobab distribution area is very large. Very rustic, it is found in most of South Sahara's semi-arid and sub-humid regions as well as in the west side of Madagascar. The plant phenology depends on the rains profile, flowering and foliation occurring during the rainy season. Pollination is done by bats. The tree can be propagated by seeding or vegetative multiplication. The fruit. It consists of (14 to 28)% of pulp with a low moisture content, acidic, starchy, rich in vitamin C, in calcium and magnesium. After separating of the seeds, the pulp is traditionally used as an ingredient in various preparations or to make beverages. In spite of some deficiency in lysine and the presence of some anti-nutritional factors, the seeds are an interesting protein source. They contain about 15% of lipids. After cooking or grilling, they are either directly consumed or used like thickeners in powder form. The leaves. They are rich in vitamins (especially C and A) and in iron, and contain mucilage (10% dm). The youngest can be consumed as vegetables, but they are often dried and then reduced into powder. Conclusion. Among the food products obtained from the baobab, the fruit pulp seems to have the strongest economic potential. Nevertheless, the local markets have to be evaluated. The development of the production of baobab fruits needs more investigation into the agronomy of the tree. Senegal / Adansonia digitata / agronomic characters / fruits / leaves Le baobab africain (Adansonia digitata L.) : principales caractéristiques et utilisations. Résumé-Introduction. Très caractéristique des zones sahéliennes, Adansonia digitata L. appartient à la famille des Bombacacées. Essentiellement exploité à l'état spontané pour ses fruits ou ses feuilles, le baobab est ancré dans les cultures traditionnelles locales. La plante. Cet arbre imposant se distingue des autres espèces d'Adansonia endémiques à Madagascar et à l'Australie par son tronc très massif (10 m de diamètre), ses fleurs à port pendulaire et sa cime arrondie. Il produit des baies sèches de (150 à 300) g, à épicarpe très lignifié, le plus souvent ovoïdes et dénommées pain de singe. Les nombreuses graines sont noyées dans une pulpe blanchâtre et farineuse. Les f...

The bissap (Hibiscus sabdariffa L.): composition and principal uses. Abstract-Introduction. Hibiscus sabdariffa L. is a herbaceous plant, cultivated largely in tropical and subtropical areas of both hemispheres. This plant is used for its fibre; mainly for its calyx, which is of three types: green, red and dark red. Composition. The red calyxes are the most used and are characterised by their concentration of anthocyanin, which can reach 1.5 g•kg-1 of dry matter. Delphinidin 3-sambubioside and cyanidin 3-sambubioside are the major anthocyanins with, respectively, (71 and 29)% of total anthocyanins. Organic acids, minerals and amino acids are present in the calyx, leaves and seeds of H. sabdariffa at variable levels depending on the variety and geographical area. Uses. The uses of different parts of H. sabdariffa are many and varied both in food and in traditional medicine. The calyx, with high concentration of acids, vitamin C and especially anthocyanins, is the most used part of the plant. It is mainly used for the production of soft drinks and tonic without alcohol. The seeds of H. sabdariffa, with their richness in protein (26%), fat (20%) and total sugars (40%), are widely used in the diet in many African countries. The leaves are a good source of nutrients and are used in Africa in the preparation of sauces. Senegal / Hibiscus sabdariffa / calyx / leaves / seeds / anthocyanins / proximate composition / uses Le bissap (Hibiscus sabdariffa L.) : composition et principales utilisations. Résumé-Introduction. Hibiscus sabdariffa L. est une plante herbacée, vivace, localisée dans les zones tropicales et subtropicales des deux hémisphères. L'espèce est exploitée pour sa fibre et principalement pour ses calices qui sont de trois types : vert, rouge et rouge foncé. Composition. Les calices de type rouge sont les plus utilisés et se caractérisent par leur concentration élevée en anthocyanes qui peut atteindre 1,5 g•kg-1. La delphinidine 3-sambubioside et la cyanidine 3-sambubioside sont les anthocyanes majoritaires avec, respectivement, (71 et 29) % des anthocyanes totaux. Les acides organiques, minéraux et acides aminés sont présents dans les calices, feuilles et graines d'H. sabdariffa à des teneurs variables suivant la variété et la zone géographique. Utilisations. Les utilisations des différentes parties de l'H. sabdariffa sont nombreuses et variées aussi bien dans l'alimentation que dans la médecine traditionnelle. Les calices, du fait de leur concentration élevée en acides, vitamine C et surtout en anthocyanes, constituent la partie de la plante la plus valorisée. Ils sont surtout utilisés pour la production de boissons désaltérantes et tonifiantes sans alcool. Les graines d'H. sabdariffa de par leur richesse en protéine (26 %), lipides (20 %) et sucres totaux (40 %) sont très utilisées dans l'alimentation dans de nombreux pays africains. Les feuilles constituent une bonne source de nutriments et sont utilisées en Afrique pour la préparation de sauces.

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