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Kinds of Dryer Selected AbstractsDRYING METHODS AND QUALITY OF SHRIMP DRIED IN A JET-SPOUTED BED DRYERJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2005RUNGTIP TAPANEYASIN ABSTRACT The objective of this study was to experimentally investigate the effects of various parameters, i.e., size of shrimp, level and pattern of inlet drying air temperature, on the drying kinetics and various quality attributes of dried shrimp viz. shrinkage, rehydration ability, texture and color during drying in a jet-spouted bed dryer. It was found that the use of a constant inlet air temperature of 100C yielded dried shrimp of the best quality in terms of low percentage of shrinkage, high percentage of rehydration, low maximum shear force and high value of redness compared to shrimp dried using other conditions. A simple mathematical model that enables prediction of the drying behavior of shrimp in a jet-spouted bed dryer has also been developed. [source] Effects of Process Parameters on Quality Changes of Shrimp During Drying in a Jet-Spouted Bed DryerJOURNAL OF FOOD SCIENCE, Issue 9 2007C. Niamnuy ABSTRACT:, The objective of the present study was to investigate the effects of various parameters, that is, concentration of salt solution (2%, 3%, 4%[w/v]), boiling time (3, 5, 7 min), drying air temperature (80, 100, 120 °C), and size of shrimp, on the kinetics of drying and various quality attributes of shrimp, namely, shrinkage, rehydration ability, texture, colors, and microstructure, during drying in a jet-spouted bed dryer. In addition, the effects of these processing parameters on the sensory attributes of dried shrimp were also investigated. Small shrimp (350 to 360 shrimp/kg) and large shrimp (150 to 160 shrimp/kg) were boiled and then dried until their moisture content was around 25% (d.b.). It was found that the degree of color changes, toughness, and shrinkage of shrimp increased while the rehydration ability decreased with an increase in the concentration of salt solution and boiling time. Size of shrimp and drying temperature significantly affected all quality attributes of dried shrimp. The conditions that gave the highest hedonic scores of sensory evaluation for small dried shrimp are the concentration of salt solution of 2% (w/v), boiling time of 7 min, and drying air temperature of 120 °C. On the other hand, the conditions that gave the highest hedonic scores of sensory evaluation for large dried shrimp are the concentration of salt solution of 4% (w/v), boiling time of 7 min, and drying air temperature of 100 °C. The quality attributes of dried shrimp measured by instruments correlated well with the sensory attributes, especially the color of dried shrimp. [source] Head lice on pillows, and strategies to make a small risk even lessINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2003Rick Speare Background Due to a lack of evidence, controversy exists about the role of bedding in the transmission of head lice. Aims To determine the proportion of the head lice population found on pillowcases of people with head lice, and to test strategies available to householders to kill head lice on pillowcases. Methods To assess the incidence of head lice on pillowcases, people with active pediculosis had their head lice collected and counted and the pillowcase they had used the night before examined for head lice. To test strategies to kill head lice on pillowcases, live head lice were experimentally placed in miniature pillowcases, and the cases were subjected to a hot wash, a cold wash, hot dryer, and hanging out to dry on an outdoor clothes line. Results Forty-eight people and their pillowcases were recruited from Townsville, Qld, Australia (dry tropics). One thousand, eight hundred and forty-five lice were collected from their heads to give an average and median intensity of infection of 38.4 and 21 lice, respectively. Two of the 48 pillowcases contained live lice, one nymph on each, 2 h and 9 h after the pillowcases had been removed from the bed. Another pillowcase contained a dehydrated nymph. The incidence of live lice on pillowcases was 4.2% per night and the proportion of the head louse population on the pillowcases was 0.11%. Heat (hot wash and hot clothes dryer) killed head lice experimentally placed in pillowcases. Cold wash and hanging pillowcases out to dry did not kill head lice. Conclusions Head lice transfer to pillowcases at night, but the incidence is low. Pillowcases pose a risk for re-infection with head lice, but the risk is low, and changing the pillowcase is a reasonably cost-efficient strategy to minimize this risk. Lice on pillowcases can be killed by heating the pillowcase by immersion in water at > 60 °C, by a hot wash, or by 15 min in a hot clothes dryer. [source] Exergetic performance assessment of a pilot-scale heat pump belt conveyor dryerINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2010Zafer Erbay Abstract In this study, olive leaves were dried in a pilot-scale heat pump (HP) belt conveyor dryer as a thin layer. Drying experiments were carried out at the drying air temperature range of 45,55°C with the drying air velocity range of 0.5,1.5,m,s,1. The performance of the system and the process was evaluated using exergy analysis method. The exergy loss and flow diagram (the so-called Grassmann diagram) of the dryer system was presented to give quantitative information regarding the proportion of the exergy input that is dissipated in the various system components. Effects of the drying air temperature and the velocity on the performance of the drying process were discussed. The actual coefficient of performance values were obtained to be 2.37 for the HP unit and 2.31 for the overall system, respectively. The most important component of the system for improving the efficiency was determined to be the compressor. Exergetic efficiencies of the drying of olive leaves were in the range of 67.45,81.95%. It was obtained that they increased as the drying air temperature decreased and the drying air velocity increased. Copyright © 2009 John Wiley & Sons, Ltd. [source] Re-circulating heat pump assisted continuous bed drying and energy analysisINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2005Phani K. Adapa Abstract Specialty crops such as ginseng, herbs and echinacea need to be dried at low temperatures (30,35°C) for product quality optimization. A drying system that is both energy efficient and preserves product quality is desired. A re-circulating heat pump continuous bed dryer system was designed, constructed and field-tested for this purpose. The heat pump dryer system was experimentally evaluated using several potential herbal and medicinal crops such as alfalfa, catnip, wormwood, red clover, portulaca, dandelion and ginseng. These crops were dried either in chopped, sliced or whole form, depending on the part of the plant (aerial or root). The specific moisture extraction rates (SMER) obtained for various crops were in the range of 0.06,0.61 kg kWh,1. It took 5 days and 190 kWh of energy to reduce the average moisture content of ginseng roots below 10% (wb), while commercial dryers currently in use would take on an average 14 days and 244 kWh of energy at comparable loading rates. The re-circulating nature of the heat pump dryer made it 22% more energy efficient and resulted in 65% reduced drying time compared to conventional dryers incorporating electric coil heaters. Copyright © 2005 John Wiley & Sons, Ltd. [source] The role of policy instruments for promoting combined heat and power production with low CO2 emissions in district heating systemsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2005Å. Marbe Abstract Policy instruments clearly influence the choice of production technologies and fuels in large energy systems, including district heating networks. Current Swedish policy instruments aim at promoting the use of biofuel in district heating systems, and at promoting electric power generation from renewable energy sources. However, there is increasing pressure to harmonize energy policy instruments within the EU. In addition, natural gas based combined cycle technology has emerged as the technology of choice in the power generation sector in the EU. This study aims at exploring the role of policy instruments for promoting the use of low CO2 emissions fuels in high performance combined heat and power systems in the district heating sector. The paper presents the results of a case study for a Swedish district heating network where new large size natural gas combined cycle (NGCC) combined heat and power (CHP) is being built. Given the aim of current Swedish energy policy, it is assumed that it could be of interest in the future to integrate a biofuel gasifier to the CHP plant and co-fire the gasified biofuel in the gas turbine unit, thereby reducing usage of fossil fuel. The goals of the study are to evaluate which policy instruments promote construction of the planned NGCC CHP unit, the technical performance of an integrated biofuelled pressurized gasifier with or without dryer on plant site, and which combination of policy instruments promote integration of a biofuel gasifier to the planned CHP unit. The power plant simulation program GateCycle was used for plant performance evaluation. The results show that current Swedish energy policy instruments favour investing in the NGCC CHP unit. The corresponding cost of electricity (COE) from the NGCC CHP unit is estimated at 253 SEK MWh,1, which is lower than the reference power price of 284 SEK MWh,1. Investing in the NGCC CHP unit is also shown to be attractive if a CO2 trading system is implemented. If the value of tradable emission permits (TEP) in such as system is 250 SEK tonne,1, COE is 353 SEK MWh,1 compared to the reference power price of 384 SEK MWh,1. It is possible to integrate a pressurized biofuel gasifier to the NGCC CHP plant without any major re-design of the combined cycle provided that the maximum degree of co-firing is limited to 27,38% (energy basis) product gas, depending on the design of the gasifier system. There are many parameters that affect the economic performance of an integrated biofuel gasifier for product gas co-firing of a NGCC CHP plant. The premium value of the co-generated renewable electricity and the value of TEPs are very important parameters. Assuming a future CO2 trading system with a TEP value of 250 SEK tonne,1 and a premium value of renewable electricity of 200 SEK MWh,1 COE from a CHP plant with an integrated biofuelled gasifier could be 336 SEK MWh,1, which is lower than both the reference market electric power price and COE for the plant operating on natural gas alone. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simulation of a new concept of an indirect solar dryer equipped with offset rectangular plate fin absorber-plateINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2005S. Youcef-Ali Abstract A simulation code was developed to predict the indirect solar dryer performance of the thin beds of discs of potato, subjected to time-varying air conditions. Two mathematical models are developed separately; the first allows the determination of the thermal performances of the solar collector with offset rectangular plate fin absorber-plate and the second, allows to determine the kinetics of drying for the data input of the air at the exit of the collector. The latter takes into account calorific losses through the walls of the dryer and shrinkage of discs. Experimental results of the solar dryer thermal performances, using sunlight in Valenciennes (in the North of France), will be compared with the results obtained by the theoretical model suggested. Copyright © 2005 John Wiley & Sons, Ltd. [source] Optimising microwave vacuum puffing for blue honeysuckle snacksINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2010Chenghai Liu Abstract Fresh blue honeysuckle fruit slices were puffed in a microwave vacuum dryer up to a final moisture content about 5% (w.b.). The effect of initial moisture content (IMC) (25,45%), vacuum pressure (VP) (70,90 kPa) and microwave intensity (MI) (10,30 W g,1) on quality attributes, in terms of expansion ratio (ER), hardness (HD), crispness (CR) and colour of the products, were analysed by response surface methodology. Besides the effect of MI on chroma (CH), the high IMC and low VP had a significantly positive impact on the quality attributes of blue honeysuckle snacks. The optimum product qualities, which were ER (1.62 times), HD (5836.31 g), CR (4.48), and CH (28.7) were obtained at an IMC of 38.42%, VP of 82.02 kPa, and MI of 22.42 W g,1. The microwave vacuum method has obvious advantages when puffing the blue honeysuckle snacks. [source] Effect of convective solar drying on colour, total phenols and radical scavenging activity of olive leaves (Olea europaea L.)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 12 2009Neila Bahloul Summary In this study, olive leaves, which are known for their therapeutic and antioxidant properties, were used to assess the effect of solar drying conditions (temperature and flow rate) on the drying time and quality parameters of olive leaves. Samples were dried at three drying temperatures (40, 50 and 60 °C) and at two drying air flow rates (1.62 and 3.3 m3 min,1) in a convective laboratory solar dryer. From the experimental results, it was noted that the drying time required to reduce the moisture content to 0.10 kg kg,1 d.b. depends mainly on the drying temperature. The quality attributes of the dehydrated olive leaf samples were investigated in term of colour, total phenols and radical scavenging activity. The effect of solar drying on L*, a* b* parameters was significant (P < 0.05) for all the studied olive leaves. Besides, the total phenols of olive leaves were significantly (P < 0.05) influenced by drying air conditions and tended to decrease with increased drying time. The DPPH radical scavenging activity was higher in fresh [EC50 39.40 (ZR)-39.95 (CH)] than in dried leaves. However, the radical scavenging activity was also high in leaves dried at 60 °C, 3.3 m3 min,1 [EC50 54.21 (ZR),68.79 (CL)]. [source] Hot air drying of yacon (Smallanthus sonchifolius) and its effect on sugar concentrationsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 11 2009Caroline Fenner Scher Summary This work aimed to experimentally study the drying behaviour of yacon tubers with and without steam blanching. Drying was carried out for 5 h and 30 min in a forced air dryer at 50 °C, 60 °C and 70 °C. The results indicated that the shortest drying time was obtained at 70 °C for blanched samples, and that the equilibrium water activity values were significantly lower for the blanched samples at all temperatures. The yacon dried without prior blanching showed lowest concentrations of reducing sugars when dried at 70 °C, significantly lower than those dried at 50 °C and 60 °C. This indicates hydrolysis of the fructo-oligosaccharides at 70 °C, a fact verified by the significant increase in reducing sugars content from 36.65 ± 0.54,44.10 ± 0.96% and reduction in the non-reducing sugars from 31.62 ± 0.55,26.18 ± 0.29%. [source] Effect of temperature and initial moisture content on sorption isotherms of banana dried by tunnel drierINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2008Zhengyong Yan Summary Sorption isotherms of intermediate moisture content (IMC) products are essential to predict shelf-life of packaged moisture-sensitive product by modelling moisture uptake during storage and distribution. The effect of temperature and initial moisture content (MC) of IMC banana on the relationship between MC and water activity were investigated. Raw bananas were dried in a tunnel dryer at 2% relative humidity (RH), 70 °C, and a 3.2 ± 0.2 m s,1 air velocity. Drying procedure was carried out a number of times until various IMC levels were obtained (5%, 14%, 22% and 33% db for banana). Sorption isotherms of bananas were determined at 10, 20, 30 and 40 °C. The initial MC of IMC banana had no significant effect on the relationship between MC and water activity according to statistical analysis. All the sorption curves were found to be Type II. BET, GAB, modified GAB, Oswin, Halsey and modified Freundlich models were fitted to the data and it was found that the best results were obtained with a modified Freundlich equation. A secondary modified Freundlich model was built accounting for the effect of aw and temperature on the sample MC. [source] Convective hot air drying of blanched yam slicesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2008Olajide Philip Sobukola Summary In this study, a laboratory convective hot air dryer was used for the thin layer drying of blanched yam slices and experimental moisture ratio was compared with Newton, Logarithmic, Henderson and Pabis, modified Henderson and Pabis, approximation of diffusion, modified page 1, two-term exponential, Verma et al. and Wang and Singh models. Among all the models, the approximation of diffusion model was found to satisfactorily describe the kinetics of air-drying of blanched yam slices. The increase in air temperature significantly reduced the drying time with no constant rate period but drying occurs in falling rate period. The effective diffusivity values varied between 7.62 × 10,8 to 9.06 × 10,8 m2 s,1 and increased with increase in temperature. An Arrhenius relation with an activation energy value of 8.831 kJ mol,1 showed the effect of temperature on moisture diffusivity. [source] Comparison of drying behaviour, quality and yield of copra processed in either a solar hybrid dryer on in an improved copra kilnINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2007Thiruchelvam Thanaraj Summary Drying copra in a solar hybrid dryer reduces the moisture content from around 50% to 7% after 71 h of continuous drying. The copra was graded as 73% white copra, 21% Milling Ordinary Grade II (M.O.GII) and the remaining 6% M.O.GIII (dusty copra). Thermal efficiency was about 10%. In the Coconut Research Institute copra kiln, the moisture content of copra was reduced from around 52% to 8% in 62 h of intermittent dying. The copra was graded as about 82% M.O.GI and the remaining 18% M.O.GIII (burnt copra). Thermal efficiency was about 15.5%. High quality white copra could be processed in solar hybrid drying. However, no white copra could be processed in kiln drying. [source] Hot air dehydration of figs (Ficus carica L.): drying kinetics and quality lossINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2004Antonio Piga Summary The dehydration of fruit from fig trees is normally achieved by sun drying. There is concern about the safety of the end product, mainly because there is a risk of the development of aflatoxins. These concerns can be overcome by artificial drying (oven dehydration). Fig fruits of a local cultivar, which were either pre-treated by blanching or blanching plus sulphuring or not treated at all, underwent hot air dehydration under mild processing conditions in a pilot airflow cabinet dryer. Sampling was carried out at regular intervals to calculate the rate of dehydration and assess quality changes. Microbiological counts and nonenzymatic browning were also monitored. Pretreatments resulted in a shorter processing time, compared with control fruits. In general, a falling dehydration rate period was observed. A dramatic loss of ascorbic acid was recorded, while an informal sensorial assay of the dried fruits gave a positive assessment. [source] APPLICATION OF DISCRETE MODELING APPROACH TO FLUIDIZED BED YEAST DRYINGJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2010F. DEBASTE ABSTRACT Yeast drying is widely used to ease transport and conservation. In this work, baker's yeast drying in fluidized bed is modeled using a pore network model. Classical balanced equations at the reactor scale are coupled with the pore network for the grain, which takes into account diffusion in the gas phase, transport by liquid film in partially saturated region and pressure gradient effects in the liquid phase. The porous structure to be applied in the model is obtained using environmental scanning electron microscopy. Simulations are validated on a thermogravimetric analysis experiment. The model is then applied to fluidized bed drying for which experimental results obtained on a laboratory pilot are available. Finally, the model results are compared to those of a simplified receding front model. PRACTICAL APPLICATIONS The presented model allows simulation of Saccharomyces cerevisiae fluidized bed drying. Taking into account transport phenomena in the grain offers the opportunity to predict drying rate without the use of a desorption isotherm. Moreover, the model predicts roughly the critical humidity. Therefore, the model can be used for scale-up, design and optimization of dryer including the effect of changes in yeast granulation. [source] INFLUENCE OF SAMPLE SIZE AND SHAPE ON TRANSPORT PARAMETERS DURING DRYING OF SHRINKING BODIESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2007NAJMUR RAHMAN ABSTRACT An experimental investigation on the influence of sample size and shape on heat and mass transport parameters under natural convection air-drying is presented. Potato cylinders with length of 0.05 m and thicknesses of 0.005, 0.008, 0.010 and 0.016 m, and circular slices with diameter of 0.05 m and thickness of 0.01 m were dried in a laboratory scale hot-air cabinet dryer. Results indicate that each transport parameter exhibits a linear relationship with sample thickness. Convective heat and mass transfer coefficients (hcand hm) decreased whereas moisture diffusion coefficient (Deff) increased with increasing thickness. Considering no sample shrinkage effect in the parameter analysis, for the thickness range considered, the values of hcare found to be underestimated in the range of 29.0,30.6%, whereas those of hmand Deff are overestimated in the range of 33.7,38.0% and 75.9,128.1%, respectively. Using Levenberg,Marquardt algorithm for optimization, a correlation for Biot number for mass transfer (Bim) as a function of drying time and sample thickness is proposed. A close agreement was observed between dimensionless moisture contents predicted by this relation and those obtained from experiments for different sample thicknesses at drying air temperature of 60C. For the same thickness and drying conditions, circular slices caused an increase in each transport parameter significantly. [source] APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR THE OSMOTIC DEHYDRATION OF CARROTSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2006BAHADUR SINGH ABSTRACT Osmotic dehydrations of carrot cubes in sodium chloride salt solutions at different solution concentrations, temperatures and process durations were analyzed for water loss and solute gain. The osmotically pretreated carrot cubes were further dehydrated in a cabinet dryer at 65C and were then rehydrated in water at ambient temperature for 8,10 h and analyzed for rehydration ratio, color and overall acceptability of the rehydrated product. The process was optimized for maximum water loss, rehydration ratio and overall acceptability of rehydrated product, and for minimum solute gain and shrinkage of rehydrated product by response surface methodology. The optimum conditions of various process parameters were 11% salt concentration, 30C osmotic solution temperature and process duration of 120 min. [source] SUPERHEATED STEAM-DRYING OF MATE LEAVES AND EFFECT OF DRYING CONDITIONS ON THE PHENOL CONTENTJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2006EVERTON FERNANDO ZANOELO ABSTRACT Four drying experiments of mate leaves (Ilex paraguariensis St. Hilaire) were carried out in a packed bed superheated steam dryer by varying outlet steam temperature from 120 to 140C and equivalent particle diameter from 4.7 × 10,3 to 6.95 × 10,3 m. The influence of these variables on the drying coefficient calculated by assuming a simplified drying kinetic model was investigated. A classical statistical approach revealed the significant effect of both factors on this parameter. Two additional drying runs were performed at identical conditions with conventional hot air and low pressure superheated steam, respectively. The influence of drying atmosphere on the total content of phenols was evaluated. A conventional process of extraction by using an aqueous methanol solution was adopted. Analyses for total phenols were performed by spectrophotometry at 715 nm by applying Folin-Denis assay. The leaves dried with superheated steam had approximately 47% higher retention of these compounds. [source] DRYING METHODS AND QUALITY OF SHRIMP DRIED IN A JET-SPOUTED BED DRYERJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2005RUNGTIP TAPANEYASIN ABSTRACT The objective of this study was to experimentally investigate the effects of various parameters, i.e., size of shrimp, level and pattern of inlet drying air temperature, on the drying kinetics and various quality attributes of dried shrimp viz. shrinkage, rehydration ability, texture and color during drying in a jet-spouted bed dryer. It was found that the use of a constant inlet air temperature of 100C yielded dried shrimp of the best quality in terms of low percentage of shrinkage, high percentage of rehydration, low maximum shear force and high value of redness compared to shrimp dried using other conditions. A simple mathematical model that enables prediction of the drying behavior of shrimp in a jet-spouted bed dryer has also been developed. [source] TWO-PHASE MODELING AND THE QUALITY OF SOYBEAN SEEDS DRIED IN A COUNTER-CURRENT MOVING BED DRIERJOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2004A.F. LACERDA ABSTRACT The purpose of the present work is to study the simultaneous heat and mass transfer between air and soybean seeds in a countercurrent moving bed dryer, based on the application of a two-phase model to the drying process. The numerical solution of the model is obtained by using a computational code based on backwards differential formulae. The experimental data of air humidity and temperature and of seed moisture content and temperature at the dryer outlet are compared to the simulated values, showing a good agreement. This work also analyzes the effect of the main process variables (drying air temperature, air relative humidity, air velocity and solids flow rate) on the soybean seeds quality during drying. Empirical equations fitted to the experimental data are proposed for predicting the soybean seed quality (germination, vigor and fissures) as a function of the investigated variables. [source] EXPERIMENTAL VACUUM SPRAY DRYING OF PROBIOTIC FOODS INCLUDED WITH LACTIC ACID BACTERIAJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2009YUTAKA KITAMURA ABSTRACT This research aims to develop a vacuum spray dryer (VSD) that performs spray drying in a vacuumed drying tower at a lower temperature than the conventional spray drying. The VSD operational drying temperatures for the probiotic foods containing lactic acid bacteria were determined by the relationships between the temperature and the vapor pressure, and were correlated by Clapeyron's equation. The drying of the fermented milk starter at 35C drying tower was experimentally possible; however, powder from the lactic fermenting beverage was not obtained even at 50C, which resulted from the lower glass transition temperature of the material. Compared with ATP concentration of the fermented milk starter before and after the VSD drying, the lower the drying temperature, the higher the microbial activity is retained. The ATP ratio as 30% of the raw materials shows the high feasibility of VSD for dairy processing. PRACTICAL APPLICATIONS During the spray drying of liquid or slurry food, the heat-sensitive functional ingredients such as vitamin, enzyme or bacteria are usually degraded or lost because of the contact with hot air between 120 and 180C. Markets need food powder that involves a lot of functional materials and a long shelf life for the expansion of healthy food. The experimental vacuum spray dryer (VSD) showed a potential to dry probiotic foods involving lactic acid bacteria without their inactivation. Although the lactic acid bacteria contained in the powder at 35C,VSD was 30% of the raw material, it is more economical than using the liquid type fermented milk starter. With some mechanical or operational modifications for the high moisture content and low recovery ratio of the powder, VSD is applicable for dairy processing factories. [source] MATHEMATICAL MODELLING OF THIN-LAYER DRYING OF KIWIFRUIT SLICESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009M DOYMAZ ABSTRACT The effect of temperature on the drying kinetics of kiwifruit was investigated. The drying process was carried out at temperatures of 50, 55 and 60C, air velocity of 2.4 m/s and relative humidity between 10,25%. Drying time decreased considerably with increased air temperature. Drying process took place in the falling rate period. Twelve mathematical models available in the literature were fitted to the experimental data. The models were compared by four statistical parameters; i.e., determination of coefficient, mean relative percent error, reduced chi-square and root mean square error, and the best-fit model was selected. The modified Henderson and Pabis and Verma et al. models were given the best results in describing thin-layer drying of kiwifruits. The effective diffusivity of water during air-drying varied from 1.743 to 2.241 × 10,10 m2/s over the temperature range investigated, with activation energy equal to 22.48 kJ/mol. PRACTICAL APPLICATIONS Drying can be described as an industrial preservation method in which water content and activity of agricultural products are decreased by heated air to minimize biochemical, chemical and microbiological deterioration. Kiwifruit has a very short life because of softening and vitamin loss during cold storage. The use of drying prolongs the shelf-life of the kiwifruit, as the water content reduction slows down deterioration reactions. In this study, drying characteristics of kiwifruits were studied in a convectional hot-air dryer. The objectives of the present study were to determine experimentally the thin-layer drying characteristics and rehydration capacity of samples, and to fit the experimental data to 12 mathematical models available from the literature. [source] EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOURJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2008A.O. SOBOWALE ABSTRACT The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48 h, and were analyzed for functional and sensory characteristics. Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability (P < 0.05). PRACTICAL APPLICATIONS Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns. [source] EFFECT OF OSMOTIC TREATMENT WITH CONCENTRATED SUGAR AND SALT SOLUTIONS ON KINETICS AND COLOR IN VACUUM CONTACT DRYINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 6 2007S.M.A. RAHMAN ABSTRACT An experimental study of osmotic dehydration (OD) of selected heat-sensitive products was carried out in a laboratory-scale vacuum contact dryer. Cubes of potato and apple were examined as model heat-sensitive objects. Experiments were conducted at different conduction heat input levels with wall temperatures in the range 35,45C under vacuum and also in pure vacuum without any external heat input. Detailed investigations were carried out of OD on drying performance, product temperature and color of the dried product. PRACTICAL APPLICATIONS Osmotic treatment of potato and apple samples using concentrated sugar solution shows better osmotic dehydration as well as drying rate in a vacuum contact drying system. This information may help to select the osmotic agent in any industrial application for faster drying rate in vacuum contact drying specially for food products. Moreover this work shows the analysis to find out the starting point of precipitation of osmotic agent inside the products in terms of drying time, temperature and moisture content. This information will be helpful for critical analysis in osmotic dehydration technique which in turns may help for optimum design. [source] EFFECT OF CaCl2 AND CONVECTIVE-OSMOTIC DRYING ON TEXTURE AND PREFERENCE OF APPLEJOURNAL OF FOOD QUALITY, Issue 6 2006L.A. OCHOA-MARTÍNEZ ABSTRACT Conventional air-drying combined with osmotic dehydration was researched as a potential method for drying apple cubes of superior quality. Samples were pretreated with CaCl2 at different temperatures and times. Pretreated apple cubes were dehydrated in a tray dryer. Then, osmotic dehydration with sucrose solutions was carried out. The curves for osmotic dehydration showed that the gain of solids was higher when 40% of water was removed by convective drying while the loss of weight was lower at the same level of dehydration at 65°Brix. Texture measurements indicated that the temperature of pretreatment affected the hardness and cohesiveness. Hardness values were higher at 40C, while cohesiveness values were lower at the same temperature. The CaCl2 at a given temperature did not have a significant effect on texture. Sensory evaluation showed that samples pretreated at 25C and osmotically dried at 50°Brix had the higher preference by the judges. [source] OPTIMIZATION OF SPRAY DRYING CONDITIONS FOR PRODUCTION OF BIFIDUS MILK POWDER FROM COW MILKJOURNAL OF FOOD QUALITY, Issue 4 2006M. SELVAMUTHUKUMARAN ABSTRACT Bifidus milk powder was prepared by supplementing cow's milk with predetermined level of additives to obtain slurry of desired concentration. The slurry was sterilized, cooled and inoculated with 24-h-old bulk culture of Bifidobacterium bifidum at 10% and incubated at 37C for 24 h, cooled and dried in SM Scientech Lab model spray dryer with predetermined spray drying conditions. The bifidus milk powder contains bifidobacteria counts from 1.88 × 109 to 15.80 × 109 cells/g dry weight and their percent survival was 4.17,35.11%. Maximum survival was obtained by using the following spray drying conditions: inlet temperature of 164.02C, slurry concentration of 25.62% total soluble solids and air pressure of 2.5 kg/cm2. The high temperature and air pressure of spray drying markedly influenced the color and appearance of final product. The inlet temperature and air pressure showed a significant effect on survival of bifidobacteria in the final product. [source] Effects of Process Parameters on Quality Changes of Shrimp During Drying in a Jet-Spouted Bed DryerJOURNAL OF FOOD SCIENCE, Issue 9 2007C. Niamnuy ABSTRACT:, The objective of the present study was to investigate the effects of various parameters, that is, concentration of salt solution (2%, 3%, 4%[w/v]), boiling time (3, 5, 7 min), drying air temperature (80, 100, 120 °C), and size of shrimp, on the kinetics of drying and various quality attributes of shrimp, namely, shrinkage, rehydration ability, texture, colors, and microstructure, during drying in a jet-spouted bed dryer. In addition, the effects of these processing parameters on the sensory attributes of dried shrimp were also investigated. Small shrimp (350 to 360 shrimp/kg) and large shrimp (150 to 160 shrimp/kg) were boiled and then dried until their moisture content was around 25% (d.b.). It was found that the degree of color changes, toughness, and shrinkage of shrimp increased while the rehydration ability decreased with an increase in the concentration of salt solution and boiling time. Size of shrimp and drying temperature significantly affected all quality attributes of dried shrimp. The conditions that gave the highest hedonic scores of sensory evaluation for small dried shrimp are the concentration of salt solution of 2% (w/v), boiling time of 7 min, and drying air temperature of 120 °C. On the other hand, the conditions that gave the highest hedonic scores of sensory evaluation for large dried shrimp are the concentration of salt solution of 4% (w/v), boiling time of 7 min, and drying air temperature of 100 °C. The quality attributes of dried shrimp measured by instruments correlated well with the sensory attributes, especially the color of dried shrimp. [source] Energy Consumption, Density, and Rehydration Rate of Vacuum Microwave- and Hot-Air Convection- Dehydrated TomatoesJOURNAL OF FOOD SCIENCE, Issue 6 2002T.D. Durance ABSTRACT: Vacuum to lower boiling temperature and microwaves for energy transfer can provide very rapid dehydration at low temperatures. Tomato sections were dehydrated in a batch convection air dryer (AD), a 16 kW vacuum microwave (VM) dryer, or by 1 of 3 combination processes. Drying rate of the 100% VM process was 18 times that of the 100% AD process. Only a slight falling rate effect was noted in VM drying AD and VM in sequence allowed the operator to choose any process time between 0.8 and 14.75 h. In this instance the least energy consumption occurred in the 100% VM process. Lowest energy cost was found for the 70% AD / 30% VM process. These results are expected to be strongly dependent upon the scale and design of dryers. Tomatoes finish-dried by VM exhibited a puffed structure associated with faster rehydration. [source] Comparison of single pot and multiphase high shear wet granulation processes related to excipient compositionJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2009K. Giry Abstract At present time, industrial production imperatives can require the transposition of a formulation from one equipment to another. In order to evaluate the impact of such a switch on the properties of granules and tablets, investigations were undertaken on formulations manufactured both in a single pot mixer-granulator-dryer (high shear granulator with in situ double jacket vacuum drying) and in a multiphase equipment (high shear granulator/fluid bed dryer). Principal component analysis highlighted the major contribution of the binder ratio on granule size distribution, flow and packing ability whereas the relative ratio of mannitol and lactose, used as fillers, mainly impacted on compressibility and tablet cohesion. In the studied domain, the lubricant ratio did not explain the considered responses. Statistical analysis (comparison of means, analysis of variance and PCA) showed that both processes led to products with similar characteristics which demonstrated the ability of the processes to produce granules with close quality. However, Fielder®/Niro® granule characteristic data were found to be more dispersed, thus demonstrating a higher sensitivity of the multiphase process to formulation changes. Technological properties of granules and tablets were found to be maintained or improved therefore securing the switch from single pot to multiphase equipments. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3761,3775, 2009 [source] Dehydration studies using a novel multichamber microscale fluid bed dryer with in-line near-infrared measurementJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2003Eetu Räsänen Abstract The purpose of this research was to study the effect of two process parameters (temperature and moisture content) on dehydration behavior of different materials using a novel multichamber microscale fluid bed dryer with a process air control unit and in-line near-infrared (NIR) spectroscopy. The materials studied were disodium hydrogen phosphates with three different levels of hydrate water and wet theophylline granules. Measured process parameters of fluid bed drying were logged, including in-line NIR signals. Off-line analyses consisted of X-ray powder diffraction patterns, Fourier transform NIR spectra and moisture contents of studied materials. During fluid bed drying, the stepwise dehydration of materials was observed by the water content difference of inlet and outlet air, the pressure difference over the bed, and the in-line NIR spectroscopy. The off-line analysis confirmed the state of solid materials. The temperature and the moisture content of the process air were demonstrated to be significant factors for the solid-state stability of theophylline. The presented setup is a material and cost-saving approach for studying the influence of different process parameters on dehydration behavior during pharmaceutical processing. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2074,2081, 2003 [source] | ||||||||||||||||||||||||||||