Thermal Properties of Sweet Potato with its Moisture Content and Temperature

Thermal properties of sweet potato were experimentally determined and modeled as a function of temperature and moisture content. The purpose is to develop empirical correlations that could predict thermal properties during sweet potato processing. Thermal conductivity from the study was 0.49 ± 0.038 Wm^?1K^?1 (mean ± s.d.), thermal diffusivity was 1.2?×?10^?7 ± 9.05?×?10^?9 m²s^?1, specific heat was 3660 ± 477.4 Jkg^?1K^?1, and density was 1212 ± 73.5 kgm^?3. All properties were determined within temperature range of 20 to 60°C and moisture content range of 0.45 to 0.75 w.b. Prediction models for the thermal properties of sweet potato were developed as a function of product temperature and moisture content with experimental data from this study. Mechanistic models were also developed for thermophysical properties of sweet potato using major food components of the product. Developed models were all presented and compared.     

Chemical composition and nutritive value of leaf protein concentrate from leucaena leucocephala

Leaf protein concentrate (LPC) was prepared from Leucaena leucocephala leaf meal (LLM). The recovery of LPC was 7.6 % and analysis showed that the LPC contained 65.91 % crude protein compared with 29.15 % of the LLM, ash content was 17.56% while levels of essential amino acids-lysine, histidine, arginine, isoleucine and leucine—were 5.57, 2.34, 5.88, 5.42 and 10.8% on a dry matter basis, respectively. The LPC had higher in-vivo digestibility than the LLM with values being 63.20 and 48.82%, respectively. The LPC diet supported growth in rats but gave lower nutritive indices than the control diet of soya bean and Guinea corn.     

Deep Fat Frying Of Foods—Transport Phenomena

Many theoretical and experimental studies have been conducted to understand the mechanisms of heat and mass transfer during deep fat frying. This, in turn, has helped in understanding transport phenomena during frying and the relationships between thermal and physical properties of the products and the frying media. Most of the studies have focused on the determination of convective heat transfer coefficient and mechanisms of moisture and oil transfer. Mathematical models also have been developed to describe and predict the process. Many studies have adopted the assumptions used for the drying process for simplification. Recently, more realistic and sophisticated models have been introduced.     

Gross composition,amino acid,phytic acid and trace element contents of thirteen cowpea cultivars and their nutritional significance

Thirteen cultivars of cowpea (Vigna unguiculata (L) Walp) were analysed for their proximate composition, amino acid, trace element and phytic acid contents. Crude protein values ranged from 206·8 to 283·8 g kg^?1 DM. The mean contents (g kg^?1) of other major nutrients were ether extract, 18·6; ash, 38·8; total dietary fibre, 121·8 and carbohydrates, 573·4. When compared with the provisional amino acid scoring pattern of FAO, all cultivars were low in methionine and high in lysine, isoleucine, leucine and phenylalanine plus tyrosine. Values for threonine and valine were variable compared with the pattern. The range of values for the chemical score was 0·61–0·74. Phytic acid values ranged from 5·10 to 10·27 g kg^?1, and the phytate: zinc molar ratios were all higher than that (15:1) above which zinc deficiency can be induced. Most of the trace elements showed wide variation in their occurrence among the cultivars. The values for zinc and iron showed less variation. The toxic elements mercury and selenium were present in varying amounts in more than half of the cultivars while tin was found in only one variety.     

Effect of Li Promoter on titania-supported Rh catalyst for ethanol formation from CO hydrogenation

The addition of 0.10 wt% Li to Rh/TiO₂ more than doubled the CO conversion for CO hydrogenation while increasing ethanol selectivity. The addition of Li also increases formation of C₂ oxygenates at the expense of C₁ species, methanol and methane. This is attributed to enhanced dispersion of Rh by Li that appears to reduce dissociation of CO, which previous studies have shown requires large ensembles of Rh atoms on the surface. Li promotion appears to increase the associatively adsorbed CO, allowing for increased H₂ chemisorption on the surface compared to the dissociative adsorption of the same number of CO atoms. This increases selectivity to ethanol compared to the unpromoted catalysts. CO-TPD shows more reactive adsorbed CO species on the Li-promoted catalyst. FTIR results suggest that Li promotion alters CO bonding at bridged or interfacial sites and its effect is more structural than electronic.     

TECHNOLOGY CHOICE AND TECHNICAL CAPACITY IN GARI PRODUCTION

This study was undertaken to assess the capacity and technology needs of women in Osun and Ondo States for gari production. The field survey was carried out by means of a structured questionnaire, administered through a participatory learning technique. At least two processing centers were visited in each Local Government Area in the two States. Altogether a total of 63 gari processing centers were visited.

Mechanical grating of (manually) peeled cassava tubers has been fully adopted, while over 88% of processors have also embraced mechanical dewatering of the grated mash. Manual sieving is still predominant as mechanical sieving devices so far introduced still present problems; Frying also remains a manual operation, though some improved frying devices are being adopted. Women involvement in the operation and management of mechanical devices is not encouraging. Processing centers utilising diesel engine as prime movers predominate (84.7%), but they mostly employ male operators. This study however reveals that given necessary training and sensitisation, women should be able to take on more managerial and operational tasks in agroprocessing ventures.

The predominant learning method of apprenticeship needs improvement, while greater attention needs to be paid to environmental issues than presently indicated by the study. Though fatal accidents have not been prevalent, safety consciousness in many of the processing centers leaves much to be desired. To redress some of the inherent problems of current technological practices, a technology profile incorporating the most feasible mechanization option for the unit operations is proposed for gari processing.