Effect of process variables on trypsin inhibitor activity (TIA), phytic acid and tannin content of extruded African breadfruit-corn-soy mixtures: A response surface analysis

Flour samples of African breadfruit, corn and defatted soybean were extruded in a Brabender single-screw extruder (DCE 330, New Jersey). Effects of process variables on trypsin inhibitor activity (TIA) and other antinutritional factors (ANFs) were verified by response surface analysis (RSA). Blending improved the protein content of the mixtures but increased the ANFs. Extrusion cooking drastically reduced TIA, phytic acid and tannin content of the extrudates by 91%, 44% and 92%, respectively. The model developed produced the highest percent variation in TIA (80%) in comparison with either phytic acid (60%) or tannin (50%). Feed composition and screw speed were the most significant (P?0.05) process variables affecting TIA. Effect of feed composition was quadratic, while that of screw speed was linear. The quadratic effects of screw speed and feed composition on tannin and phytic acid were also significant (P?0.05).     

Development of a regional food composition table for West Africa

Knowledge of the nutrient content of foods is fundamental for virtually all nutrition-related projects, programmes and policies. Low quality compositional data may lead to inappropriate policies and funds spent unnecessarily. Existing food composition tables (FCT) for most West African countries date back to 1960 and 1970 and contain in general few foods and components without documentation. As a result of the recommendations by the Economic Community of West African States (ECOWAS) Nutrition forum and other high level meetings, FAO/INFOODS, WAHO/ECOWAS and Bioversity International developed the West African FCT. It contains 472 foods and 28 components. Emphasis was given to include data on food biodiversity by incorporating cultivars/varieties and underutilized foods. The West African FCT enables users to address diet-related health problems, strengthen local development, enhance trade and promote biodiversity. In addition it contributes to poverty alleviation in both rural and urban areas. The FCT needs to be updated regularly and it is the most recent example of INFOODS for regional food composition activities.     

The nutrient composition of three cuts obtained from P-class South African pork carcasses

The shoulder, loin and leg from P-class pork carcasses were used to determine the nutrient composition of both raw and cooked cuts. Significantly lower fat content were observed in the current study for the leg (5.21 g/100 g) and loin (6.99 g/100 g) compared to the shoulder cut (10.32 g/100 g). The overall percentage fat for all three cuts was less than 10% which is recommended by the South African Heart Mark. The cooked loin cut contained the most protein (27.50 g/100 g) of the three cooked cuts. When compared to other meat products (beef, mutton and chicken) it is clear that pork is a good source of B vitamins, especially vitamin B₃. The cooked loin cut contained the least vitamin B₁ (0.22 mg/100 g), B₂ (0.02 mg/100 g) but the most vitamin B₃ (7.09 mg/100 g), of the three cooked cuts. The 100 g cooked shoulder, loin and leg cuts provide on average 40.11% protein, 5.19% magnesium, 3.37% calcium, 24.29% phosphorus, 18.22% zinc, 22.33% iron and 22.50% vitamin B₁, 2.57% vitamin B₂ and 42.6% vitamin B₃ of Recommended Daily Allowances for males, age 25–50. Energy from a 100 g portion provides 5.81% of the Recommended Daily Allowances. To conclude, the pork cuts are undoubtedly a good source of nutrients that is required for good health because it is high in protein, have a low fat content and are a nutrient-packed choice for the family and compares favourably with the fat, energy, and cholesterol content of many other meats and poultry.     

Utilization of African grains for sourdough bread making

Abstract: Acha and Iburu flours were singly subjected to sourdough fermentation with previously selected autochthonous starters. Sourdoughs were used (30%, wt/wt) as aroma carriers and acidifiers during short time fermentation with the addition of baker's yeast. Acha and Iburu sourdough breads were compared to wheat sourdough bread started with the same strains and to breads made with the same formula but using baker's yeast alone. During Acha and Iburu sourdough fermentations, starter lactic acid bacteria reached almost the same cell density found in wheat sourdoughs. Acidification was more intense. Iburu sourdough bread had the highest total titratable acidity, the lowest pH, and contained the highest levels of free amino acids and phytase activity. The values of in vitro protein digestibility did not differ between Acha sourdough and wheat sourdough breads, while Iburu sourdough bread showed a slightly lower value. Acha and Iburu sourdough breads showed lower specific volume and higher density with respect to wheat sourdough breads. Nevertheless, Acha and Iburu sourdough breads were preferred for hardness and resilience. As shown by sensory analysis, Acha and especially Iburu sourdough breads were appreciated for color, acid taste and flavor, and overall acceptability. Practical Application: This study was aimed at evaluating the technological and nutritional properties of the African cereals Acha and Iburu. Sourdough fermentation and the use of selected starters increased the nutritional and sensory qualities and the potential application for bakery industry.     

Bioaccessibility of provitamin A carotenoids in bananas (Musa spp.) and derived dishes in African countries

Bananas and plantains (Musa spp.) constitute an important component of the diet in Africa. Substantial levels of provitamin A carotenoids (pVACs) in Musa fruit have been reported, but the bioaccessibility of these pVACs remains unknown. In this study, we used an in vitro digestion model to assess the bioaccessibility (i.e. the transfer into micelles) of pVACs from boiled bananas and derived dishes using the Eastern Democratic Republic of Congo as a study context. In particular, the effect of different food ingredients added to boiled bananas on pVAC’s bioaccessibility was studied. The bioaccessibility of all-trans β-carotene ranged from 10% to 32%, depending on the food recipes, and was modified, particularly when pVACs-rich ingredients (palm oil/amaranth) were added. Efficiency of micellarization of all-trans β-carotene was similar to that of all-trans α-carotene and depended on the cultivar (Musilongo, plantain type, 16%; Vulambya, East African cooking type, 28%), while that of the 13-cis isomer was higher (21–33.5%). Taking into account bioaccessibility, the estimated vitamin A activity was significantly different across the different Musa-based dishes tested. Results are discussed in terms of recommendations to help reduce vitamin A deficiency in Musa-dependent African communities.     

Pectinolytic and cellulolytic activities of heat resistant fungi and their macerating effects on mango and African mango

Five heat resistant fungi (HRF), Neosartorya fischeri, N fischeri var spinosa, N quadricincta, Paecilomyces varioti and Byssochlamys nivea, were studied for production of pectinolytic and cellulolytic activities. All isolates produced considerable hydrolase, lyase and pectinesterase activities. Hydrolase activities were significantly higher in fruit tissue (mango and African mango) media than in pectin medium (P < 0.01) when assayed by both cup plate and viscometric methods. Activities produced in both fruit media were comparable in N fischeri, N fischeri var spinosa and P varioti but not in N quadricincta and B nivea. All isolates produced greater lyase activities in pectin medium than in fruit tissue media except for N quadricincta, while the converse was the case for pectinesterase. P varioti did not utilise carboxymethyl cellulose or produce cellulase activity. Other isolates produced cellulase with B nivea producing the greatest activity. Each isolate caused considerable maceration of artificially inoculated mango and African mango fruits, which is not directly related to measurable pectinase or cellulase. The possibility of co‐operation between pectinase and cellulase activities in the disintegration of fruit tissues is discussed. © 1999 Society of Chemical Industry     

Managing Water Services Through Service Differentiation and Pricing in an African City

A key challenge for managers of water utilities in developing countries is to provide services to the rising urban population in a financially sustainable manner. The paper examines the management of water services in an African city which piloted service differentiation and pricing. Among the key findings was that substantial improvement in the provision of water services to the urban poor was attained. Cost recovery was achieved through innovative structuring of public/private partnerships, an appropriate pricing policy, and flexible payment systems. The project demonstrates that (a) by structuring service delivery with appropriate pricing, utilities could serve more customers (including people living in informal settlements) at affordable cost and achieve financial sustainability, and (b) service differentiation and appropriate pricing has the potential to improve urban water services in low-income countries.     

中非铜矿带多层位成矿特征及成因

中非铜矿带位于刚果(金)—赞比亚的Lufilian造山带,新元古界加丹加超群发育有大量的沉积岩容矿层状铜矿(SSC),为了解铜矿床的成矿特征和矿床成因,对矿床地质特征进行总结,发现中非铜矿带主要为还原相型和砂岩型层状铜矿床,具有明显的多层位层控特征.其中加丹加铜钴矿带(KCB)盛产还原相型铜矿床,主要赋存于Roan群M...     

African Americans and boys: Understanding the literacy gap, tracing academic trajectories, and evaluating the role of learning-related skills.

In this study, the authors examined the racial and gender gap in the academic development of African American and White children from kindergarten to 5th grade. Their main goal was to determine the extent to which social and behavioral factors, including learning-related skills, problem behaviors, and interpersonal skills, explain these gaps and shed light on the academic difficulties specifically experienced by African American boys. The authors utilized the Early Childhood Longitudinal Study–Kindergarten Cohort (ECLS-K) sample and applied growth curve modeling. Learning-related skills explained the literacy development of African American boys over and above the effects of problem behaviors, socioeconomic status, and home literacy environment. Results suggest that emphasis placed on the behavior problems and the social risk factors associated with African American boys needs to be refocused and should be accompanied by increased efforts to improve learning-related skills in the classroom context and beyond. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

非洲兰花香素的合成

非洲兰花香素的关键香气成分是 3 甲基辛酸甲酯。以巴豆酸为原料经酯化反应及在CuI催化条件下的Michael加成反应两步制备出目标物 ,总产率可达到 6 1%