Modeling of thin layer drying characteristics of blanch-assisted water yam (Dioscorea alata) slices

The thin layer drying characteristics of blanch-assisted water yam slices were investigated with respect to its un-blanched water yam slices in a convective hot air oven. The yam slices (diameter 4 cm; thickness 0.8 cm) were dried at temperatures 50, 60 and 70 °C, respectively with a constant air velocity of 0.13 m/s. The drying data obtained were fitted into six existing drying models: Page, Newton, Midilli, Henderson and Pabis, Logarithmic and Diffusion model. Non-linear regression analysis was used to determine the model parameters; the coefficient of determination (R2) and standard error of estimates (SEE) in order to determine the model best fit. The study showed that the drying process occurred in the falling rate drying period. The blanch-assisted slices had a faster drying rate than the un-blanched yam slices. Among the models, the diffusion model gave the overall best fit for the drying data obtained. The effective moisture diffusivity ranged from 3.18×10-8 to 4.47×10-8 m2/s for the blanch-assisted slices and from 4.73×10-8 to 7.33×10-8 m2/s for the un-blanched slices. The activation energies of the blanch-assisted and un-blanched yam slices were 15.5 kJ/mol and 20.1 kJ/mol, respectively. These processing conditions obtained for water yam flour would be suitable for its process design and control thereby enhancing its utilization and overall acceptability

The influence of drying on the physical properties of sweet potato slices

The effects of varying drying conditions on the physical properties of sweet potato slices were studied. Fresh tubers were peeled, washed and cut into two shapes (rectangular: 50 x 60 mm and cylindrical 60 mm diameter) of two thicknesses (4 and 6 mm) slices. Some slices were blanched in water at 90oC for 5 mins and some unblanched. Both were either sun dried or oven dried at various temperatures; 50 oC , 70 oC and 90 oC. The bulk density, dimensional changes and moisture loss were investigated. The results shown that, moisture loss and percent shrinkage increased with increased in temperature. Sweet potato of 4 mm thick samples lost more moisture with higher % shrinkage than 6 mm thick samples, although not significantly (P>0.05). Logarithmic equations gave best fit of moisture loss with time at the different temperatures. Generally, in all the samples, thickness had a greater influence on % shrinkage than shape. Blanching minimized %shrinkage although not significantly (P>0.05). Greater shrinkage took place in the sample thickness (up to 63%) than across product diameter or thickness (values up to 26.3%). % shrinkage can be predicted using either the linear or logarithmic equations. The bulk densities of dried sweet potato slices were not influenced by blanching

Bread-slicing machine

This study developed a compact front loading machine for slicing loaves of bread.  The machine is fast, efficient, safe and easy to operate.  It was designed to accommodate a normal loaf of bread per pass.  It works on the principle of gravity loaf in-feed system and the up-and-down reciprocating motion of the blade frame that carries 22 parallel cutting blades spaced at a regular interval of 14.5 mm apart.  It is driven by a 2 horsepower electric motor via a V-belt power transmission system.  The moving components are born on self-lubricating bearings and specially designed vibration absorbers; it automatically stops to save running cost once the loaf is completely sliced.  It also incorporates a crumb collection tray to enhance the hygiene of the process. Evaluation tests revealed that increasing the cutting speed above the standard commercial bakery speed of 420 r/min increased bread wastage and reduced uniformity of slice thickness

The Effects of Age on Some Physical Properties of Oil Palm Fruitlets

The study investigated the effect of age on some physical properties of Dura and Tenera cultivars of oil palm fruitlets. Fresh fruit bunches of Tenera and Dura were obtained from three different oil palm plantations corresponding to their age of cultivations: 20, 30 and 50 years.  Physical properties of their fruitlets were measured at different moisture contents using ASAE standard. The result shown that, as age increases from 20 to 50 years, mass of Tenera fruitlets increases from 7.25 to 14.89 (g), while Dura fruitlets increases from 3.71 to 11.56 (g). The sphericity of Dura cultivars increased from 80 to 87%, while that of Tenera fruitlets decreased from 81 to 64%. However, true densities of Dura and Tenera cultivars increased from 978.56 to 1180.32 (kg/m3) and 973.04 to 1160.14 (kg/m3) respectively, while bulk densities increased from 720.50 to 882.25 (kg/m3) and 680.41 to 865.92 (kg/m3) respectively.  The effect of age on mass, axial dimension, coefficient of static friction, true and bulk densities for Dura and Tenera cultivars fruitlets were significantly different (

Some quality properties of yellow-fleshed sweet potato flour as affected by different drying methods

Abstract This study compared some quality properties of yellow-fleshed sweet potato flour samples as affected by pretreatments (0.02% sulfite; blanching 85 °C for 3 min 30 s and steam blanching 100 °C for 2 min) and drying methods (oven, sun, and drum drying). The physicochemical composition, functional properties, pasting profile, and least gelation concentration of the flours were determined. Before pretreatment, the sweet potato tubers were sorted, weighed, rinsed, peeled, and diced. The smallest particle size (58 μm) was recorded for samples blanched at 85 °C followed by oven drying while drum-dried samples had the largest particle size (119.5 μm). The pH values (5.58 - 5.90) of the pretreated sun- and oven-dried samples were significantly (p<0.05) impacted by 0.02% sulfite. Compared to other drying methods. drum-dried samples had low bulk density (0.36 g/ml), the highest water (531%) and oil absorption capacities (168.5%,) and the least dispersibility (35%). Drum-dried samples had the highest swelling capacities at 60 – 80 °C but the values decreased at 80 – 90 °C compared to samples from other drying methods that had low swelling capacity at 60 - 70 °C but the values increased as the temperature increased from 70 – 90 °C. Results of the sample pasting profiles showed that pretreatment and drying techniques were significant on the various viscosities measured. Drum-dried samples had the lowest trough viscosity (18.13 RVU), final viscosity (24.88 RVU), setback viscosity (6.75 RVU), peak time (1.07 min), and pasting temperature (0 °C). This study concluded that the pretreatment and drying methods affected the quality properties of the yellow-fleshed sweet potato flour samples differently, consequently altering their functionality. Graphical Abstrac

Technological Capability of Local Fabricators in Fabrication of Equipment for Special Palm Oil in Nigeria

This study assessed some fabricators’ technical knowhow in the production or fabrication of machines used for the production of Special Palm Oil (SPO). The study also examined facilities possessed by the fabricators &nbsp;&nbsp;with the aim to providing intervention that would abridge the widening demand gap between the demand and supply of SPO for domestic and industrial applications. Multistage sampling technique was used to select 98 fabricators as respondents across four geopolitical zones where palm oil is produced in Nigeria. &nbsp;A well-structured questionnaire and an observant check list were used to collect data relevant to the objectives of the study from the respondents. The collected data were collated with Epidata application and analysed with the Statistical Package for the Social Sciences (SPSS). Descriptive statistics&nbsp; such as&nbsp; frequency distribution and mean were used to summarised the data while inferential statistics such as&nbsp; Chi-Square &nbsp;and &nbsp;multiple regression were used to make deductions. Findings of the study showed that&nbsp; &nbsp;majority&nbsp; of the respondents were&nbsp; within the age of &nbsp;bracket of 40 and 49 &nbsp;and had West African Examination Certificate or its equivalent as major educational qualification./ Average income generated per year based on their primary occupation and other occupation were ₦300,000 and ₦275,,000&nbsp; respectively. There was a great significant relationship between membership of organization and the information received at p = 0.05 probability level. Majority of the respondents said they learned the art of fabrication informally from someone. They had limited and dysfunction number pieces of equipment for bending, rolling and lathing, which hindered, the fabrication of machines involved in the production of special palm oil (SPO)