The Development of a Multi Purpose Wet Food Sieving Machine

Wet sieving is still a manual operation in tropical crop processing. It is a time consuming operation. Most of the existing wet sieving machines are available in large scale industries and they are too sophisticated to operate and maintain by local processors. Therefore, a motorized starch extracting machine, based on shaking mechanism was designed, fabricated and tested to solve the problem associated with sieving of starch and other agricultural crops in Nigeria. The machine consists of a hopper, a mixing compartment, a sieving compartment operated by a crank and spring arrangement, collecting trays and outlets.  The volumetric flow rate and the capacity of the machine are 0.0206 m3/h and 22.45 kg/h respectively. The test considered concentration at three levels 12.2 %, 14.44 % and 22.77 %. The study showed that the machine performance coefficients and sieving capacity increased with decreasing concentration. Also, highest performance coefficients  of 98% was obtained for sieving of maize while sieving capacity of 16.90g/sm2 was obtained when the machine was used to sieve cassava. A unit of the machine costs N19, 480.00 as at April 2007. The maintenance of the machine is simple and recommended for small holders, local processors and home use

CASSAVA FLOUR SUBSTITUTION AND MOISTURE CONTENT VARIATION ON SOME QUALITY CHARACTERISTICS OF HEAT PUMP DRIED EXTRUDED FISH FEED

This study examined the effect of substitution of maize with cassava flour at varying moisture contents on heat pump drying and some quality attributes including strength properties, durability index, micro-structure and floatability. The samples identified as S1- S6, were prepared from various levels of cassava flour before being extruded at steady state at 3 moisture contents (30, 35, and 40% db) in a single screw cooking extruder. Drying was done with an open loop heat pump dryer while a scanning electron microscope (FEG-SEM) was used to study the microstructure of the fish feeds. Results showed that drying rates and pellet durability were proportional to the source and concentration of starch in the samples. Some of the samples floated in water.   The Coefficient of performance (COP) of the heat pump used for the drying decreased with increase in ambient temperature; the average COP being 4.77. The thermal efficiency of the heat pump dryer was 92.45%. The scanning electron microscopy indicated that cassava substituted samples lack some elements required of fish feed. Also, extrusion cooking resulted in changes in mineral composition of fish feed blends.     &nbsp

EFFECT OF EXTRUSION PROCESSING CONDITIONS OF A LOCALLY DEVELOPED EXTRUDER ON THE PRODUCT TEMPERATURE OF SELECTED STARCH CROPS

Product temperature is a very important system parameter as well as an indicator of extrusion process. In this study, the product temperature response of a single screw extruder developed locally was investigated for the extrusion process of the flour and starch of maize and cassava which are grown in Nigeria in large quantity but with high post-harvest losses. These were compared with wheat flour which is commonly used for the production of alimentary pastes. A factorial experiment in completely randomized design was employed to study the effect of extrusion variables: feed moisture (30, 40, 50 %), extruder temperature (40, 70, 100oC) built up by varying the duration of sampling and screw speed (100, 150, 200 rpm) on Product temperature.   A maximum temperature of 150oC was attained in 30 minutes through viscous dissipation and up to a moisture loss of 55% w.b. Also, product temperature is strongly related to the starch type and the extrusion process parameters under study. Product temperature decreased with increasing moisture content. The highest values of product temperature were demonstrated by maize starch and cassava flour extrudates while the lowest values were observed on maize flour and wheat flour extrudates. Generally, it was easier for cassava to cook/gelatinize under the heat provided by the extruder. Maize starch requires more shear/cooking to form than cassava starch. This extruder is by far more cost efficient for cassava than other products i.e. Maize and wheat. Process Parameters were expected to have effects on the product temperature of the final extrudates. Thus, model-fitting using response surface methodology was performed to examine their effect on product temperature. Quadratic coefficients fit the extrusion data very well, better than linear models. Furthermore, additional research could optimize product temperature for a specific product application. The equations relating the various dependent and independent variables were established to predict the performance of the machine.     &nbsp

Variation in postoperative outcomes of patients with intracranial tumors: insights from a prospective international cohort study during the COVID-19 pandemic

Background: This study assessed the international variation in surgical neuro-oncology practice and 30-day outcomes of patients who had surgery for an intracranial tumor during the COVID-19 pandemic. Methods: We prospectively included adults aged ≥18 years who underwent surgery for a malignant or benign intracranial tumor across 55 international hospitals from 26 countries. Each participating hospital recorded cases for 3 consecutive months from the start of the pandemic. We categorized patients’ location by World Bank income groups (high [HIC], upper-middle [UMIC], and low- and lower-middle [LLMIC]). Main outcomes were a change from routine management, SARS-CoV-2 infection, and 30-day mortality. We used a Bayesian multilevel logistic regression stratified by hospitals and adjusted for key confounders to estimate the association between income groups and mortality. Results: Among 1016 patients, the number of patients in each income group was 765 (75.3%) in HIC, 142 (14.0%) in UMIC, and 109 (10.7%) in LLMIC. The management of 200 (19.8%) patients changed from usual care, most commonly delayed surgery. Within 30 days after surgery, 14 (1.4%) patients had a COVID-19 diagnosis and 39 (3.8%) patients died. In the multivariable model, LLMIC was associated with increased mortality (odds ratio 2.83, 95% credible interval 1.37–5.74) compared to HIC. Conclusions: The first wave of the pandemic had a significant impact on surgical decision-making. While the incidence of SARS-CoV-2 infection within 30 days after surgery was low, there was a disparity in mortality between countries and this warrants further examination to identify any modifiable factors