Optimization of Aqueous Extraction of Anthocyanins from Hibiscus sabdariffa L. Calyces for Food Application

Aqueous extracts of Hibiscus sabdariffa calyces are worldwide used for the production of several products such as polyphenolic-antioxidant containing beverages. However, optima conditions for extraction of polyphenolics such as anthocyanins from this plant species were unknown. For this, the influence of particle size and calyx/water ratio on the anthocyanins extraction and biochemical composition during extraction were investigated using bright red and dark red Hibiscus sabdariffa calyces.Results showed that the pH of the bright red calyces was 2.24 ± 0.01 corresponding to 12.66 ± 0.15 g/100g dry weight (DW) titratable acidity equivalent of malic acid. The pH of the dark red calyces was 2.15 ± 0.01 corresponding to 15.44 ± 0.15 g/100g DW titratable acidity equivalent malic acid. Total sugars content was 3.24±0.04 and 3.13±0.06 g/100g DW for bright red and dark red, respectively. Proteins content ranged from 4.56 ± 0.04 to 6.96 ± 0.17 g/100g DW. The level of the total phenols ranged from 3.82 ± 0.33 to 5.22 ± 0.08 g/100g DW. Average anthocyanins content was 2.61 ± 0.11 and 2.98 ± 0.02 g/100g DW for dark red and bright red calyces, respectively. Calyces were found to show an antioxidant capacity of up to 300 µmolTrolox equivalent/100g. For all calyx/water ratios, the anthocyanins content increased with extraction time till 60 min and remained almost stable thereafter.The optimization of the aqueous extraction was obtained at the ratio 1/10 (calyx/water) for the production of roselle concentrated extract, using calyces size less than 250 µm,at 30°C, for one hour percolation. Keywords: Hibiscus sabdariffa L, anthocyanins water, calyx/water ratio, particle size, optimization, extraction

Assessment of the physiological and biochemical characterization of a Lactic acid bacterium isolated from chicken faeces in sahelian region

The aim of this work was the examination of the microbiological and technological properties of a lactic acid bacterium (CWBI-B623) isolated from chicken faeces in sahelian region (Burkina Faso). The strain CWBI-B623 is a Gram positive rod, asporogenous, catalase-positive, facultatively anaerobic, non motile and mesophilic. The analysis showed that it produce L(+)-lactic acid via homofermentative pathway and it was able to ferment an important number of the carbohydrates of API 50CHL system. The 16S-rDNAsequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a subline within the Lactobacillus casei cluster. The minimal inhibitory concentration of CWBI-B623 for bile salts was higher than 1% and the survival rates to acidity with pH 3.0 and pH 2.5 were 26 and 1.2%, respectively. CWBI-B623 is an Lactobacillus casei species based on its physiological and biochemical properties and it could be a good candidate for probiotic formulations.Key words: Lactic acid bacteria, Lactobacillus, probiotic, biodiversity

Conservation de riz-paddy sous atmospheres controlees : aspects microbiologiques et consequences technologiques

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Survival and preservation after freeze-drying process of thermoresistant acetic acid bacteria isolated from tropical products of Subsaharan Africa

Two thermoresistant acetic acid bacteria (TAAB) were previously isolated and selected for a sustainable development of vinegar fermentation in Subsaharan Africa. Their use as a starter culture in vinegar manufactures in such regions could reduce considerably water cooling expenses. For optimising biomass preservation, the effect of 20% w/w mannitol as cryoprotectant on the cells viability after freeze-drying process and during storage was evaluated. Results showed that freeze-dried cells could be conserved at 4 degrees C for at least 6 months without loss of viability. The main reasons were that cryoprotectant tends to lower the water activity (a(w)) and to maintain a temperature of product weaker than that of the glass transition temperature T-g. Furthermore, the heat resistance of freeze-dried cells during storage was all the more increased that strains were cryoprotected. In addition, intrinsically, an increase of saturated fatty acids with the temperature is the essential modification in the lipidome level of membrane cells when the fermentation occured at a temperature of 30 degrees C. Tolerance to heat during storage was significantly enhanced under such mechanisms. (c) 2006 Elsevier Ltd. All rights reserved

Full Length Research Paper - Assessment of the physiological and biochemical characterization of a Lactic acid bacterium isolated from chicken faeces in sahelian region

The aim of this work was the examination of the microbiological and technological properties of a lactic acid bacterium (CWBI-B623) isolated from chicken faeces in sahelian region (Burkina Faso). The strain CWBI-B623 is a Gram positive rod, asporogenous, catalase-positive, facultatively anaerobic, non motile and mesophilic. The analysis showed that it produce L(+)-lactic acid via homofermentative pathway and it was able to ferment an important number of the carbohydrates of API 50CHL system. The 16S-rDNAsequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a subline within the Lactobacillus casei cluster. The minimal inhibitory concentration of CWBI-B623 for bile salts was higher than 1% and the survival rates to acidity with pH 3.0 and pH 2.5 were 26 and 1.2%, respectively. CWBI-B623 is an Lactobacillus casei species based on its physiological and biochemical properties and it could be a good candidate for probiotic formulations

Variability of vitamins B1, B2 and minerals content in baobab (<i>Adansonia digitata</i>) leaves in East and West Africa

The regional variability and age–age correlation on vitamin B1, vitamin B2 and minerals (Ca, Mg, P, K, Cu, Fe, Mn, Na, and Zn) concentration in baobab leaves were investigated. Baobab was cultivated from seeds from 11 countries including Benin, Burkina Faso, Kenya, Malawi, Mali, Mozambique, Niger, Tanzania, Togo, Senegal, and Sudan. Vitamins B1 and B2 content were assessed using microbiological VitaFast kits methods and minerals by atomic absorption and flame spectrometry methods. Overall, the results showed a higher content of vitamin B2 compared to vitamin B1 with the highest vitamin B2 content (1.04 ± 0.05 mg/100 g DM) from Senegal. The highest iron (Fe) content of 26.39 mg/100 g was found in baobab leaves from Mali. For age–age correlation, adult baobab leaves of Nankoun in Burkina Faso provided the highest calcium (Ca) content of 3373 mg/100 g. However, for provenance trial, young plants from three communities of Burkina Faso showed the highest calcium (Ca) and potassium (K) content. The study demonstrated that vitamins B1 and B2 and mineral contents in baobab leaves vary with the country and the age of the tree. Vitamin B1 content was higher in baobab leaves from ascendants compared to those from descendants, while in contrast vitamin B2 content was higher in the leaves from the descendants compared to their ascendants (mother tree)

Improving the efficiency of scale-up and deployment of community health workers in Mali: A geospatial analysis.

Optimising the scale and deployment of community health workers (CHWs) is important for maximizing geographical accessibility of integrated primary health care (PHC) services. Yet little is known about approaches for doing so. We used geospatial analysis to model optimised scale-up and deployment of CHWs in Mali, to inform strategic and operational planning by the Ministry of Health and Social Development. Accessibility catchments were modelled based on travel time, accounting for barriers to movement. We compared geographic coverage of the estimated population, under-five deaths, and plasmodium falciparum (Pf) malaria cases across different hypothetical optimised CHW networks and identified surpluses and deficits of CHWs compared to the existing CHW network. A network of 15 843 CHW, if optimally deployed, would ensure that 77.3% of the population beyond 5 km of the CSCom (community health centre) and CSRef (referral health facility) network would be within a 30-minute walk of a CHW. The same network would cover an estimated 59.5% of U5 deaths and 58.5% of Pf malaria cases. As an intermediary step, an optimised network of 4 500 CHW, primarily filling deficits of CHW in the regions of Kayes, Koulikoro, Sikasso, and Ségou would ensure geographic coverage for 31.3% of the estimated population. There were no important differences in geographic coverage percentage when prioritizing CHW scale-up and deployment based on the estimated population, U5 deaths, or Pf malaria cases. Our geospatial analysis provides useful information to policymakers and planners in Mali for optimising the scale-up and deployment of CHW and, in turn, for maximizing the value-for-money of resources of investment in CHWs in the context of the country's health sector reform. Countries with similar interests in optimising the scale and deployment of their CHW workforce may look to Mali as an exemplar model from which to learn

Improving the efficiency of scale-up and deployment of community health workers in Mali: A geospatial analysis

Optimising the scale and deployment of community health workers (CHWs) is important for maximizing geographical accessibility of integrated primary health care (PHC) services. Yet little is known about approaches for doing so. We used geospatial analysis to model optimised scale-up and deployment of CHWs in Mali, to inform strategic and operational planning by the Ministry of Health and Social Development. Accessibility catchments were modelled based on travel time, accounting for barriers to movement. We compared geographic coverage of the estimated population, under-five deaths, and plasmodium falciparum ( Pf ) malaria cases across different hypothetical optimised CHW networks and identified surpluses and deficits of CHWs compared to the existing CHW network. A network of 15 843 CHW, if optimally deployed, would ensure that 77.3% of the population beyond 5 km of the CSCom (community health centre) and CSRef (referral health facility) network would be within a 30-minute walk of a CHW. The same network would cover an estimated 59.5% of U5 deaths and 58.5% of Pf malaria cases. As an intermediary step, an optimised network of 4 500 CHW, primarily filling deficits of CHW in the regions of Kayes, Koulikoro, Sikasso, and Ségou would ensure geographic coverage for 31.3% of the estimated population. There were no important differences in geographic coverage percentage when prioritizing CHW scale-up and deployment based on the estimated population, U5 deaths, or Pf malaria cases. Our geospatial analysis provides useful information to policymakers and planners in Mali for optimising the scale-up and deployment of CHW and, in turn, for maximizing the value-for-money of resources of investment in CHWs in the context of the country’s health sector reform. Countries with similar interests in optimising the scale and deployment of their CHW workforce may look to Mali as an exemplar model from which to learn. </p