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Effect of Drying Methods on Composition, Sensory Evaluation and Rheological Value of Pupuru (Fermented Cassava Product)
Osundahunsi,Oluwatooyin Faramade
Journal of Food Technology , 2013,
Abstract: The effects of oven, solar cabinet and smoke drying methods on the composition, physicochemical, sensory and pasting characteristics of Pupuru, fermented cassava flour were evaluated. Irrespective of the drying method, there was no appreciable change in the proximate composition. Oven and solar cabinet-dried Pupuru had moisture contents of 12.2 and 12.1%, respectively while smoke-dried had 12.9% moisture content. The cyanide content appreciably reduced in the fermented-dried samples in comparison to fresh cassava tubers. Results obtained from pasting characteristics showed that solar cabinet-dried Pupuru had the highest peak viscosity (2250 BU) while smoke-dried sample had the least (1570 BU) peak viscosity. Oven dried sample was shown to be most stable in terms of the gelatinization temperature. Oven-dried sample had -100BU retrogradation value (Set-back) and 520BU gel values. Sensory evaluation revealed that Pupuru dried with smoke was rated significantly (P<0.05) higher than the solar-cabinet and oven-dried samples in terms of aroma, but least in colour, although taste and overall acceptability were not affected.
Mathematical Modelling of the Garification of Fermented Cassava Mash
E.C. Osoka,B.I. Oruh
Journal of Food Technology , 2013,
Abstract: The drying kinetics of fermented cassava mash (gari), during the falling rate period, was studied in three dimensions, with respect to the progression of a drying front that has its geometry evolving axis-symmetrically in a direction towards the center of the particle and progresses at the same rate as the rate of removal of moisture from the particle. The model equation based on Fick’s second law was solved numerically in spherical coordinates and the average moisture content for each incremental interval (in dimensionless terms) plotted against dimensionless time values. The moisture content versus time curve had a good fit (R2 = 0.9997) with a model of the general form, MR = A exp (-ktn). The model was validated by using it to fit kinetic data from the drying of cassava particulate in a fluidized bed at 50 C.
Theoretical Model for Predicting Moisture Ratio during Drying of Spherical Particles in a Rotary Dryer  [PDF]
F. T. Ademiluyi,M. F. N. Abowei
Modelling and Simulation in Engineering , 2013, DOI: 10.1155/2013/491843
Abstract: A mathematical model was developed for predicting the drying kinetics of spherical particles in a rotary dryer. Drying experiments were carried out by drying fermented ground cassava particles in a bench scale rotary dryer at inlet air temperatures of 115–230°C, air velocities of 0.83?m/s–1.55?m/s, feed mass of 50–500?g, drum drive speed of 8?rpm, and feed drive speed of 100?rpm to validate the model. The data obtained from the experiments were used to calculate the experimental moisture ratio which compared well with the theoretical moisture ratio calculated from the newly developed Abowei-Ademiluyi model. The comparisons and correlations of the results indicate that validation and performance of the established model are rather reasonable. 1. Introduction Rotary drying is a very complicated process that can be applied not only to thermal drying but also movement of particles within the dryer. Several authors have carried out investigations on the steady state modeling of the rotary drying process. Static models are in general differential equations, and they are suitable for investigation of static distributions. Myklestad [1] was the first to obtain an expression to predict product moisture content throughout a rotary dryer based on drying air temperature, initial moisture content, and product feed rate. Thin layer drying equations contribute to the understanding of the heat and mass transfer phenomena in agricultural products and computer simulations for designing new and improving existing commercial drying processes [2]. They are used to estimate drying times of several products and also to generalize drying curves. In thin layer drying model, the rate of change in material moisture content in the falling rate drying period is proportional to the instantaneous difference between material moisture content and the expected material moisture content when it comes into equilibrium with the drying air [3]. Many authors have developed semiempirical models based on the diffusion theory to predict the drying kinetics of moist substances in thin layer as shown in Table 1 (where MR is the moisture ratio). The constants , , , , , , and in eight models by most authors have been found to be functions of inlet air temperature, inlet air velocity, humidity, and so forth, the mass of feed was not accounted for by all the authors and in the drying of substances with high moisture content like fermented ground cassava, dairy products, and some pharmaceutical product in rotary dryer, and the mass of feed should be accounted for in the thin layer drying equation. It
Thin- layer drying of diced cassava roots
STAR Kajuna, VCK Silayo, A Mkenda, PJJ Makungu
African Journal of Science and Technology , 2001,
Abstract: Fresh cassava (Manihot spp) roots were obtained from a farm and used in this study. They were peeled and diced using a special dicing machine into cubes of side 0.5 cm. The cubes were dried in thin layers (one to three layers) in a drier that was specifically designed and fabricated in the Department of Agricultural Engineering and Land Planning, Morogoro, Tanzania for the purpose. The drier had a motor driven fan, a heater and a tray chamber, with thermometers for determining entry and exit temperature (dry and wet bulb) conditions of the air. The input variables were: depth of thin layer (0.5, 1.0 and 1.5 cm), drying temperature of the air (55 and 65 oC) and drying time (from 0 min until the sample attained equilibrium, at intervals of 25 min). The response variable was the moisture content of the cassava cubes. Weather conditions during the experiments were also monitored. A parallel sun drying experiment was carried out to compare thin layer drying on the sun and thin layer drying in the fabricated dryer. For the fresh cassava that was used in the experiments, a duplicate sample was placed in an oven at 75 oC for 7 hours to determine the initial moisture content. The results indicated that the average moisture content of fresh cassava roots was about 75.4 %(w.b.). Both temperature and depth of layers were found to affect the drying characteristics of cassava cubes, with single layer and higher drying temperature giving faster approaches to equilibrium moisture content. Comparing sun drying of one layer at an average temperature of 25 oC with artificial drying at the above named temperatures, it was found that sun drying took 2 to 3 days to reduce the moisture content to Equilibrium Moisture Content (EMC), while this was achieved within 150 min and 125 min with artificial drying at 55 oC and 65 oC respectively. The generally accepted thin layer drying equations were fitted to the drying data of cassava cubes, and the Page model was found to agree with the drying data of one, two and three layers with high accuracy for artifial drying, but not for sundrying. The exponential model only agreed accurately with drying of one layer.
Prediction of the Drying Rates of Cassava Slices During Oven Drying
U.J. Etoamaihe,K.O. Ibeawuchi
Journal of Engineering and Applied Sciences , 2012, DOI: 10.3923/jeasci.2010.308.311
Abstract: Fresh cassava (Manihot sp.) NR 8082 tubers were peeled and diced into cubes of size thicknesses 5 and 10 mm, respectively. The cubes were dried in thin layers in an oven drier. Thicknesses (x = 5 and 10 mm) drying temperatures of the air (70 and 80°C) and drying times (from 0 min until the sample attained equilibrium, at intervals of 10 min). The response variable was the moisture content of the cassava slices. Results showed that high temperatures and smaller thickness of slices resulted in faster approaches to equilibrium moisture content of the samples. Two drying models namely page and exponential models were used to compare with the obtained experimental data. The drying data of the cassava slices fitted well with Page model with high accuracy for artificial drying (R2>0.9). The predicted and experimental results were very much in agreement.
Convection in Drying and Freezing Ground  [PDF]
Mir Faizal,Stephen Peppin
Physics , 2012,
Abstract: In this paper we analyse the drying of a soil composed of particles, water and solute impurities, and study the occurrence of convective instabilities during evaporation. We find that the main driving force for instability is the formation of a concentration gradient at the soil surface due to the evaporation of water. A similar phenomenon may occur during the thawing of frozen ground in Arctic regions.
Effect of length of fermentation on the functional characteristics of fermented cassava 'fufu'
O.B. Oyewole, S.L. Ogundele
Journal of Food Technology in Africa , 2001,
Abstract: Cassava clones 30572 was fermented to 'fufu' for different period of time ranging from zero hour to 96 hours. The quality of the 'fufu' produced as a result of different duration of fermentation was assessed. The fermentation processes were characterized with acid production but the level of acidification increased with the duration of fermentation. The yield of 'fufu', the bulk density and the dispersibility increased with increasing period of fermentation. When subjected to sensory evaluation, the preference of the panelists for the characteristic 'fufu' texture and odour increased with increased length of fermentation. Except for the 'fufu' made without fermentation ( 0 h), there was no significant difference in the colour of the 'fufu' fermented for different length of time. For all the attributes rated ( texture, odour, colour, overall acceptability), there was no significant difference between the 'fufu' fermented for 72 hours and 96 hours. A fermentation period of 72 hours was recommended for the production of good quality 'fufu' when using the cassava clone TMS 30572. The Journal of Food Technology in Africa Volume 6 Number 2 (April-June 2001), pp. 38-40
Nutritional Evaluation of Cassava Root Meal Fermented with Rumen Filtrate
Adeyemi O.A.,D. Eruvbetine,T. Oguntona,M. Dipeolu,O.E. Fasina,H.A. Awojobi,J.A. Adefowora
Journal of Food Technology , 2013,
Abstract: The study reported herein evaluates with rats the nutritional quality of cassava root meal (CRM) fermented with rumen filtrate using Caged Layer Waste (CLW), Pig Excreta (PE) and a 1:1 mix of CLW and PE respectively as sources of nitrogen. Some safety aspects regarding possible feed use were also investigated. Wistar rats were fed five purified diets viz: a basal diet (nitrogen free), a reference diet that contained casein and three test diets made of the enhanced CRM. Dietary treatments significantly influenced performance, biological indices and blood parameters (p<0.05). The performances of rats on the enhanced cassava diets were inferior to that of rats on casein diet. The level of serum urea and thiocyanate were significantly elevated for rats on the cassava-based diets compared to the casein diet. Among the enhanced cassava test protein, Protein Efficiency Ratio (PER) values of 0.88, 0.57 and 0.62; Net Protein Ratio (NPR) values of 0.27, -0.15 and 0.03 and Biological Value (BV) of 55.04, 39.96 and 52.27 were obtained respectively for cassava enhanced with Caged Layer Waste (CCLW), Cassava Enhanced with Pig Excreta (CPE) and cassava with 1.1 mix of caged layer waste and pig excreta (CCLPE). The result obtained from rats on CCLW was significantly better than the other enhanced cassava products.
Non dimensional analysis of cassava transient drying in packing beds  [cached]
H. Santamaria,N. Durango,A. Bula,M. Sanjuan
Latin American applied research , 2011,
Abstract: Transient mass transfer process is analyzed for cassava drying (Manihot Esculenta Crantz) in a pack bed. Experiments were performed in a thermally insulated radial dryer, considering cylindrical pieces of non peeled cassava with three different thicknesses: 4, 6, and 8 mm. The void fractions considered were 0.22, 0.49, 0.64 and 0.66, while the temperature values were 50oC and 70oC. The humidity removed from the cassava was measured from 10 pieces randomly selected at the beginning of the process. These pieces were weighed every 15 minutes during a three hours period. From the data gathered a non linear regression model was attained as a function of non dimensional numbers, which is valid for the following ranges: 700≤Re≤1900, 10000≤Sc≤31000, 0 Keywords Drying --- Mass Transfer --- Transient --- Cassava --- Food
The Effect of Adding “Tape Singkong” (Fermented Cassava) Juice on the Characteristics of Fermented Milk  [PDF]
Salam N. Aritonang,Elly Roza,Sri Novalina
Pakistan Journal of Nutrition , 2012,
Abstract: This study aimed to evaluate the effect of adding “Tape Singkong” juice on the characteristic of fermented milk. In the study 4000 ml of milk was used and divided into 20 cups (200 ml/cup). A completely randomized design that consist of five treatments with four replications was used to analyze the data. The treatment are the giving tape singkong juice as much as 0% (A), 22.5% (B), 5% (C), 7.5% (D) and 10% (E) into the milk that contained 2% of Lactobacillus acidophilus. The variable was observed the characteristic of fermented milk that consist of the moisture, fat, lactose and alcohol content, acidity and bacteria colony count. The result of this research indicated that the addition of tape singkong juice up to 7.5% was significantly decreased the content of moisture, fat and lactose and increased acidity, alcohol content and bacteria colony count.
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