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.

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.

Carbohydrate and aglycon moieties released, respectively, by acid and enzymatic hydrolysis of African mango pulp extracts containing glycosidically bound compounds were identified by TLC, GC, and GC/MS. Glucose was found to be the most important sugar constituent of the glycoside saccharidic moiety, while significant amounts of arabinose and trace amounts of rhamnose were detected. Several aglycons [(Z)-hexen-3-ol, hexanol, hexanoic acid, 2,5-dimethyl-4-hydroxy-3-(2H)furanone (furaneol), linalool oxides, α-terpineol, carvacrol, vanillin, cis- and trans-6-p-menthen-2,8-diol, 1,8-p-menthadien-7-ol, 1-p-menthen-7,8-diol, and 9-hydroxymegastima-4-en-3-one] were identified as additional mango bound volatile compounds. Fatty acids (myristic and stearic acids) were also found in glycosidically bound form. Ten glycosides (benzyl, 2-phenylethyl, and α-terpineyl glucosides and rutinosides, eugenyl, vanillyl and furaneyl glucosides and α-terpineyl arabinoglucoside] were identified for the first time in mango by GC/MS of trifluoroacetylated derivatives and GC using reference compounds. Linalyl oxide glucosides (four isomers) and C13 norisoprenoid derivatives [9-hydroxymegastima-4,6-dien-3-one (two isomers), 9-hydroxymegastima-4,7-dien-3-one, and vomifoliol glucosides and arabinoglucosides] were tentatively identified. Keywords: Mango; glycosidically bound compounds; TFA derivatives; GC/MS

--Introduction. The baobab tree (Adansonia digitata L.) grows wild in Senegal where the fruit is consumed in various forms. Although the plant ecology and botany have been well studied, works relating to the fruit processing or the impact of processing on the quality of the final products are rare. In order to evaluate the technological potential of these fruits, as a precondition to the development of their processed products on the local, regional and international markets, we attempted to characterize the raw material better (biochemical composition and nutritional quality), and we studied the processing of the product into nectar. Materials and methods. Our study related to twelve without-shell fruit samples of A. digitata collected between 2004 and 2006 in various zones of Senegal. Proportions of the various components of the fruit (pulp, seeds, fibers) were assessed, then various physico-chemical characteristics of the pulp and seed were analyzed. The microbial flora present in traditionally prepared drinks was studied. Pasteurization techniques and crossflow microfiltration of nectars were applied. Various uses and traditional fruit processing were evaluated starting from a survey carried out with a sample of 93 people questioned in Dakar and Saly. Results and discussion. The pulp was characterized by a low water content (6-15%), a strong acidity (68-201 mEq·100 g -1 ) and high contents of sugars (20-32%), ascorbic acid (125-312 mg·100 g -1 ), minerals (6%) and starch (41-47%). The chromatograms obtained by GC/MS on the fruit pulp identified 10 aroma compounds, especially isopropyl myristate, an unidentified phenolic compound and nonanal. Without special precaution, the pulp composition evolved during storage and its quality was quickly degraded. The survey carried out showed that the fruit pulp of the baobab tree is mainly used for the development of ] for a volumetric reduction ratio ranging between 1 and 2. These low permeate fluxes compromise the potential of crossflow microfiltration for the stabilization of the nectar. Conclusion. In the future, from the point of view of a local production of nectar from the baobab tree fruit, research will have to be focused on the thermal stabilization of drinks.Senegal / Adansonia / fruit juices / keeping quality / pasteurizing / microfiltration Caractérisation du fruit du baobab et étude de sa transformation en nectar.Résumé --Introduction. Le baobab (Adansonia digitata L.) est un arbre qui pousse à l'état sauvage au Sénégal où le fruit est consommé sous différentes formes. Si l'écologie et la botanique de la plante ont été bien étudiées, les travaux portant sur la transformation du fruit ou sur l'impact des traitements de transformation sur la qualité des produits finis sont rares. Afin d'évaluer le potentiel technologique de ces fruits, en préalable au développement de leurs produits de transformation sur les marchés locaux, régionaux et internationaux, nous avons cherché à mieux caractériser la matière première (composition biochimique et qualité nut...

Bissap (Hibiscus sabdariffa L.) production in Senegal. Abstract-Production area. Introduced in the XIXth century, H. sabdariffa L. is grown throughout the territory of Senegal, particularly in the Kaolack, Djourbel, Thies, Saint-Louis and Louga regions. Agricultural practises. In these areas, cultivated surfaces vary between (0.25 and 5) ha and are managed for the most part by women who are grouping together more and more in associations or economic interest groups. It is grown in the winter period in a cycle of (120 to 165) days, depending on traditional practises, and usually without fertilizer. The harvest and post-harvest treatments are carried out manually, while drying is carried out in the sun and often directly on the floor. Varieties. Two types of H. sabdariffa are found: the green and red types. The red type includes mainly four varieties (Vimto, Koor, CLT 92 and Thai) with different characteristics. Transformation. The main processing activities of the H. sabdariffa calyx are crushing, and the production of drink and concentrate, jam and instant powder. The manufacture of beverages, the main method of transformation, carried out under the direction of women's groups, has remained virtually artisanal. Markets. With a support program of the Senegalese state, the increase in the cultivated areas and the number of actors, H. sabdariffa occupies an important place in the marketing of agricultural products in Senegal. The export of dried calyx of H. sabdariffa to Europe and the United States at prices between (1,000 and 2,500) $US•t-1 is increasing year by year. Senegal / Hibiscus sabdariffa / vegetable growing / interest groups / processing / markets La production du bissap (Hibiscus sabdariffa L.) au Sénégal. Résumé-Zones de production. Introduit au XIX e siècle, le bissap (H. sabdariffa L.) est cultivé sur l'ensemble du territoire sénégalais et plus particulièrement dans les régions de Kaolack, Djourbel, Thiès, Saint-Louis et Louga. Pratiques agricoles. Dans ces régions, les superficies utilisées varient entre (0,25 et 5) ha et sont gérées pour la majeure partie par des femmes qui se regroupent de plus en plus en association ou en groupement d'intérêt économique. La plante est cultivée en période d'hivernage sur un cycle de (120 à 165) j selon des pratiques traditionnelles, généralement sans apport d'engrais. La récolte et les traitements post-récoltes sont effectués manuellement et le séchage est réalisé au soleil, souvent à même le sol. Variétés. Deux types d'H. sabdariffa sont rencontrés : le type vert et le type rouge qui comprend essentiellement quatre variétés (Vimto, Koor, CLT 92 et Thaï) aux caractéristiques différentes. Transformation. Les principales activités de transformation des calices d'H. sabdariffa sont le concassage, la production de boisson, de concentré, de confiture et de poudre instantanée. La fabrication de boisson, principale voie de transformation, effectuée sous la direction de groupements féminins est restée quasiment artisanale. Marchés. Bénéficiant d'un programme d'appui de l'...