Showing papers by "Rivers State University of Science and Technology published in 1992"

Proximate composition and functional properties of raw and processed full‐fat fluted pumpkin (Telfairia occidentalis) seed flour

Abstract: The proximate composition and functional properties of raw, germinated and fermented full-fat fluted pumpkin (Telfairia occidentalis Hook) flour were studied. Functional properties evaluated by laboratory studies were nitrogen solubility, water and fat absorption, bulk density, foam capacity and stability. Germination increased the crude protein, ash, crude fibre, iron and total phosphorus but decreased the carbohydrate and fat contents. Nitrogen solubility was pH dependent with a minimum at pH 4.0 and a maximum at pH 10.0 for the raw flour. Maximum nitrogen solubility (70%) was recorded for germinated flour, which also showed excellent fat absorption properties. Raw flour was significantly higher (P < 0.05) in water absorption capacity than the processed flours. Germination and fermentation diminished bulk density, foam capacity and stability of fluted pumpkin flour. Raw full-fat fluted pumpkin flour showed comparatively better water and fat absorption properties than raw full-fat soya flour. Hence it may prove to have useful applications in fabricated foods such as bakery products and ground meat formulations.

Root distribution of Acioa barteri, Alchornea cordifolia, Cassia siamea and Gmelina arborea in an acid Ultisol

Abstract: A major constrait to alley cropping is the competition of tree or shrub roots with those of companion food crops for available water and nutrients in the topsoil. Root distribution patterns of Acioa barteri, Alchornea cordifolia, Cassia siamea and Gmelina arborea grown on an acid Ultisol at Onne in the humid forest zone of southeastern Nigeria were examined to a depth of 120 cm and laterally to 200 cm from the tree trunk to study the suitability of the species for alley cropping. The four woody species have roots throughout the soil profile examined but differ in the concentration of roots both laterally and vertically. Alchornea cordifolia, Cassia siamea and Gmelina arborea, in spite of higher underground biomass production, most of their fine roots (<2 mm diameter) were in the top 20 cm of the soil. This soil layer had 73%, 76%, and 74% of the total Alchornea cordifolia, Cassia siamea, and Gmelina arborea fine roots in the profile examined, respectively. Such root systems would compete with food crops for nutrients and moisture in the surface soil. Alchornea cordifolia and Gmelina arborea have many large woody roots in the surface soil which will make any tillage operation or seedbed preparation difficult. Acioa barteri in contrast, has the desirable rooting system with fewer fine roots in the surface soil (49%), and roots that are concentrated close to tree trunk and decrease markedly away from the tree base. In addition, Acioa barteri roots penetrate deeper soil horizons and can result in more efficient nutrient cycling from these layers, and reduced competition with shallow-rooted food crops. The rooting distribution patterns of Acioa barteri indicated that the species is a promising alley shrub in acid soils of the humid forest ecology. Therefore, consideration of rooting characteristics of potential tree/shrub species is recommended for the development of agroforestry systems such as alley cropping.

Changes in cassava toxicity during processing into gari and ijapu--two fermented food products.

Abstract: Grated cassava to which tap water was added at levels of 25%, 50% and 75% (v/w) was held at 30°C, 40°C or 50°C and examined over a 6h period for cyanide content, pH and titratable acidity (TTA). During the come‐up time, i.e. the time between addition of water and attainment of desired holding temperature (between 14 and 47 min), reductions in bound cyanide of ca 54–85% occurred, depending on the level of added water and holding temperature. The corresponding losses for the control samples, to which no water was added, were ca 25–33%. The biggest reduction in the bound cyanide of >99% (from 89.0 to 0–6 ppm) occurred in grated cassava with 75% added water held at 50°C. There was little or no change in pH during the period of study. The reduction of processing time for certain cassava products based on separation into detoxication and flavour development/fermentation stages is discussed.

Vegetation recovery and herbaceous production in a freshwater wetland 19 years after a major oil spill

Abstract: Summary After a major oil spill in a fresh water wetland, the oil was set ablaze as a clean-up measure. Nineteen years later the vegetation structure of the wetland was analysed for evidence of and information about vegetation recovery. Our results indicate that vegetation in the area (zone ‘H’) which received the direct impact of the spill is recovering but vegetation in areas downstream of the spill site (zone ‘M’) is presently being degraded due to a slow seepage of persistent crude oil from the spill site. Herbaceous production (including food crops) was negatively correlated with hydrocarbon concentrations in the soil. The present results suggest that burning as a clean-up measure is ineffective, at least in wetland ecosystems. Resume Apres une grave pollution petroliere dans un marecage d'eau douce, le petrole a ete brule pour etre elimine. Dix-neuf ans plus tard, on a analyse la structure de la vegetation du marecage pour servir de temoignage et d'information sur sa restauration Nos resultats montrent que la vegetation de l'endroit (zone H) qui a recu directement la pollution est en train de se retablir mais que celle de l'endroit qui se trouve en aval (zone M) est actuellement en train de se degrader a cause d'un suintement lent mais persistant de petrole en provenance de l'endroit du deversement. La production herbacee (y compris les cultures) etait inversement liee a la concentration des hydrocarbures dans le sol. Ces resultats suggerent que le fait de bruler les hydrocarbures est inefficace pour nettoyer un endroit pollue, en tout cas dans les ecosystemes marecageux.

Lipids of Arthrobacter siderocapsulatus

Abstract: E.N. AMADI AND G. ALDERSON. 1992. The results of lipid studies confirm that Arthrobacter siderocapsulatus is not a member of the genus Arthrobacter. Further studies are required to determine the taxonomic status of these Gram-negative bacteria.

Competition between the phycitid moths Plodia interpunctella (Hubn.) and Ephestia cautella (Wlk.) in groundnuts and on a laboratory diet.

Abstract: Competition between Plodia interpunctella (Hubn.) and Ephestia cautella (Wlk.) was studied in groundnuts and in a limited amount of standard medium (maize meal, wheat bran and glycerol at the ratio of 8:8:1) (w/w) when the species were reared separately (conditions PI and EC), when one was added before the other (conditions P+E/2 and E+P/2) and when both were introduced together (condition PI/EC). Separately, each species was well maintained on the standard medium, while E. cautella was the better competitor in groundnuts under conditions E+P/2 and PI/EC. The results offer a possible explanation for the pest status and distribution of the two moths species in groundnuts and where their ranges overlap, especially in the tropics.

Habitat preference and seasonal variations of phlebotomine sandflies (Diptera, Psychodidae) in Marigat area, Baringo District, Kenya.

Abstract: A number of natural and man-made habitats in Marigat area of Kenya were surveyed for sandflies in 1985/86. Of the 98,573 adult sandflies collected, 2.7 % belonged to the genus Phlebotomus and 97.3% to Sergentomyia . Relative abundance of sandflies of the genus Phlebotomus was four times higher in burrows than in termite hills, while sandflies of the genus Sergentomyia collected from termite hills were twice as numerous as those from burrows. Termite hills had the highest sandfly population compared to other sites, followed by tree holes and animal burrows. Fifteen species were identified, of which five belonged to Phlebotomus and 10 to Sergentomyia . The most abundant and widespread species were Sergentomyia antennatus, S. bedfordi, S. ingrami, Phlebotomus martini, S. schwetzi, S. africanus and P. duboscqi . Sandflies of both genera were present for the greater part of the year. Most species of sandflies decreased in numbers during the dry season. High population densities of sandflies were recorded during the wet period. Correlations between relative abundance of sandfly vectors of leishmaniases and rainfall were positive. However, none of the correlation coefficients was statistically significant.

Magnetic effect on low Reynolds number flow in a heated tube of slowly varying section

Abstract: A mathematical model is advanced for blood flow in an axisymmetric heated tube in the presence of a uniform magnetic field. The radius of the tube is assumed to to vary slowly in the axial direction. Using asymptotic series analysis about a small parameter, e, solutions are obtained for the velocity components, temperature and pressure. The effect of the magnetic field on the axial velocity is discussed quantitatively.

Catalytic cracking in presence of an aromatic addition

Abstract: Fluidized bed catalytic cracking of vacuum gas oil fractions in the presence of extract from phenol purification of heavy lubricating oil fraction as an aromatic addition was investigated. Results show that, at the optimum concentration of the addition, coke formation on the catalyst decreases by 50 to 70% while the content of olefinic hydrocarbons in gasoline decreases, with a corresponding increase in the content of paraffin/naphthene hydrocarbons. The yield of gasoline increases, while its octane number increases by about two units.

A shock hodograph in collisionless plasma

Abstract: In this paper, the shock hodograph (polar) for a collisionless transverse shock has been developed in the plane of the flow deflection angle and total pressure jump. The sonic point on the hodograph lies closer to the characteristic than to the point of maximum flow deflection for an attached shock. This hodograph is particularly useful in the analysis of three shock confluences and refraction of shock waves at gas interfaces. The first analysis is fully described in this paper. It is observed that the third shock wave is forward facing. It is pertinent to note that the limited region of supersonic flow also restricts the occurrences of three shock interactions.