Drying

Direct foaming of colloidal suspensions is a simple and versatile approach for the fabrication of macroporous ceramic materials. Wet foams produced by this method can be stabilized by longchain surfactants or by colloidal particles. In this work, we investigate the processing of particle-stabilized wet foams into crack-free macroporous ceramics. The processing steps are discussed with particular emphasis on the consolidation and drying process of wet foams. Macroporous alumina ceramics prepared using different consolidation and drying methods are compared in terms of their final microstructure, porosity, and compressive strength. Consolidation of the wet foam by particle coagulation before drying resulted in porous alumina with a closed-cell structure, a porosity of 86.5%, an average cell size of 35 lm, and a remarkable compressive strength of 16.3 MPa. On the other hand, wet foams consolidated via gelation of the liquid within the foam lamella led to porous structures with interconnected cells in the size range from 100 to 150 lm. The tailored microstructure and high mechanical strength of the macroporous ceramics can be of interest for the manufacture of bio-scaffolds, thermal insulators, impact absorbers, separation membranes, and light weight ceramics.

In current work, the effects of drying temperature (40, 60, and 80ºC), relative humidity (20%, 30%, and 40%) and air velocity (1.0, 1.5, and 2.0 m/s) on drying kinetics of Savory leaves were investigated in a forced convective dryer in order to optimize the drying conditions. nine most used empirical thin layer models were applied on experimental data which were selected to describe the drying behavior of the savory leaves. The selected thin layer drying models were fitted to the experimental drying curves using direct least square and the coefficients of the models were estimated under each drying air condition. The best fit was determined by using three statistical parameters: higher values of coefficient of determination (R 2) and lower sum square errors (SSE) and root mean square error (RMSE) were used, respectively. According to the statistical analysis, the Midilli et al. model was considered as the best models describing the drying curves of savory leaves by higher correlation of the coefficients and lower reduced SSE and RMSE. Effective moisture diffusivity was calculated on the basis of Fick's second law. The moisture diffusion coefficient varied between 6.76143×10-12 and 1.57018×10-10 m 2 /s for range of temperatures considered in different air dryer conditions and corresponding activation energy varied between 42.07 and 44.74189 kJ/mol.

An innovative method was developed to study the specific uncoupled effect of temperature and water activity (Aw) during mango drying. Thermal treatment of reconstituted lyophilized mango powder at targeted Aw enabled evaluation of the inactivation of polyphenol oxidase and peroxidase activity in a range 0.98-0.6 Aw and a time-temperature range of 1-4 h and 50-60 C. We established that thermal treatment of the enzymatic extract was not the same as the inactivation phenomena that occurred in the mango matrix, mainly due to differences in the pH of the buffer extract (6.4) and reconstituted food matrix (3.8). Even if the inactivation of these two enzymes was directly correlated with the temperature of the treatment, this behavior was also strongly linked to the Aw. A two-step change in the fruit was observed at high Aw (i.e., at 0.98 in fresh fruit), polyphenol oxidase (PPO) was shown to be more thermostable than peroxidase (POD), whereas when evaporation reduced the Aw to around 0.6, the opposite behavior was observed. As a consequence, enzymatic inactivation during drying should be considered as the result of the coupled effects of time-temperature and water activity.

Moisture extraction rate Efficiency Water heat exchanger Low air flow rate a b s t r a c t This paper explores the feasibility of a novel design of household clothes tumbler dryer, where the electrical elements of a standard tumbler clothes Dryer A (which heat the ambient air entering the drum) were replaced by a water-to-air finned tube heat exchanger (Dryer B). To achieve the objective of the study, experimental performances of the two dryers (e.g., Dryers A and B) were evaluated for the same operating conditions. During the experiments, Dryer B was found to have shorter drying times, lower moisture extraction rates for the same power input and hence significantly more efficient than Dryer A. This type of dryer may be adopted by the industry in the future for its relatively low cost, higher energy efficiency and environmental benefits.

The set of coupled heat and mass transfer equations are developed to predict the effect of far-infrared irradiation in a series paddy drying process, comprising fluidized bed drying, transport of paddy, far-infrared irradiation, tempering and ambient air ventilation. Two layers inside a paddy grain, i.e. a penetrating layer and a conductive layer, were introduced in the development. Comparison results showed that the model predicted results agreed well with the experiments within the maximum differences in the average paddy moisture content and temperature of 2.5% d.b. and 5°C, respectively. Furthermore, the model was capable of reasonably predicting the temperature and moisture distributions inside a paddy grain.

A mathematical model of plug flow fluidized bed dryers has been formulated. The model was based on analytical equations previously derived to simulate well-mixed fluidized bed dryers, combined with axial dispersion theory. It was implemented on Microsoft Excel 2000; the calculations were fully automated with the aid of a macro programmed in Visual Basic. The model outputs include moisture, temperature and specific energy consumption profiles along the length of the dryer, the condition of the outlet streams, and the overall specific energy consumption. The effects of dryer geometry and the principal operating parameters were investigated and followed logical trends. Dispersion had a negligible effect on the results under the industrially realistic conditions employed in the simulations. The outlet moisture content of the solids was found to depend on the difference between the temperature and dewpoint of the exhaust air and the drying kinetics. Specific energy consumption increased with decreasing outlet moisture content and was in good agreement with values calculated assuming an ideal adiabatic dryer.

A systematic experimental investigation of contact drying operation was carried out in an agitated Charles Thompson filter-dryer. In this study, the effect of process parameters (wall temperature, impeller speed, fill level) on the drying performance in the filter-dryer is quantified as a function of bed temperature and solvent concentration. In addition, the impact of drying conditions on the particle size distribution was also examined. It was found that in the range of parameters investigated, drying rate increased with wall temperature and reduced bed depth. The effect of impeller speed was variable where favorable drying conditions were strongly dependent on the particle properties. Moreover, decrease in the particle size was evident with an increase in impeller speed and decrease in the bed depth due to increased collision frequency and reduction in the fill volume both leading to particle attrition respectively. Besides, the average wall to solid heat transfer coefficient is also estimated for variable operating conditions.

The use of moulds as a seasoning for sausage can have both desirable and undesirable consequences. The desirable consequences are the creation of a successful product that appeals to consumers. The undesirable consequences are due to the growth of undesirable moulds that produce highly toxic secondary metabolites referred to as mycotoxins. The aim of the paper was to investigate the presence of moulds producing ochratoxin A (OTA) on the surface of sausages from northern Italy. A total of 757 mould strains were isolated from sausage casings. The most frequently identified species were Penicillium nalgiovense, Penicillium oxalicum, Eurotium amstelodami, Penicillium olsonii, Penicillium chrysogenum, Penicillium verrucosum, Penicillium viridicatum, and Eupenicillium crustaceum. Aspergillus ochraceus was detected in only one production lot. Approximately 45% of these samples were positive for the presence of OTA. On the casings of the investigated sausages, the lowest and highest OTA values were 3 and 18 mg/kg, respectively.

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Fresh persimmons were subjected to two different processes: sun-drying during 1 month and dehydration at 60 °C during 12 h. To assess the effect of this process on nutritional and health-related properties of persimmons dietary fibers, minerals, trace elements, ...

Conventional drying technologies generally rely on drying processes driven by using hot air, where these processes have significantly high energy consumption and greenhouse gas emissions. With our knowledge based on the limited nature of fossil fuels and the impact of climate change, it is clear that every technology has to be cleaner, cheaper, and more efficient to limit our carbon footprint while maintaining sustainable development. In this regard, the present study comprehensively reviews the recent advances in drying technologies and energy consumption and the efficiency and economic performances of several alternative drying technologies. The reviewed drying technologies include adsorption mediated, agitated thin film, electrotechnologies, hybrid systems, impingement, heat pumps, microwave, ohmic-heating, refractance window, rotating drum, superheated steam, and vacuum. The selected performance criteria are final heat use, final electricity use, primary energy use, thermal and energy efficiencies, and operating cost. With these criteria taken into account, the results show that the refractance window has the highest sustainability ranking (8.28/10), and superheated steam has the lowest sustainability ranking (2.90/10). Besides, the sustainability of the different drying fuels and technologies is conducted, and the results show that renewables have the highest sustainability ranking. Besides, it is seen that some novel approaches in drying, such as solar-based hybrid drying systems and refractance window drying, are amongst the most promising sustainable technologies. They could be the key to clean, affordable, reliable, and efficient drying of different kinds of products in industrial processes.

At harvest time, maize (Zea mays L.) has a moisture content too high to be stored, and has to be dried. To control the drying impact on maize characteristics, it is necessary to accurately know the spatial distribution of temperature and moisture content in the kernel, and the kinetics of quality loss in relation to these two factors. To this end, a physical model of heat and mass transfer in a maize kernel was designed. The Fick and Fourier equations were solved by the finite element method (FEM). The real 3D geometry of maize was obtained by NMR imaging and then used to build the mesh needed for the FEM computations. The model correctly describes the evolutions of maize moisture and salt-soluble protein content during fluidized-bed drying with a constant drying air temperature between 50°C and 100°C.

The ability to model and predict the formation of desiccation cracks is potentially beneficial in many applications such as clay liner design, earth dam construction, and crop science, etc. However, most studies have focused on statistical analysis of crack patterns and qualitative study of contributing factors to crack development rather than prediction. Because it is exceedingly difficult to capture the nonlinear processes during desiccation in analytical modelling, most such models handle crack formation without considering variation of material properties with time, and are unattractive to use in realistic modelling. The data obtained from laboratory experiments on clay soil desiccating in moulds were used as a basis to develop a more refined model of desiccation cracking. In this study, the properties, such as matric suction, stiffness and tensile strength of soil, and base adhesion, could be expressed approximately as functions of moisture content. The initial conditions and the development of suction due to desiccation and the varying material properties were inputted to UDEC, a distinct element code, using its internal programming language FISH. The model was able to capture some essential physical aspects of crack evolution in soil contained in moulds with varying lengths, heights, and materials of construction. Extension of this methodology is potentially beneficial not only for modelling desiccation cracking in clay, but also in other systems with evolving material properties such as concrete structures and road pavements. NUMERICAL MODELLING OF DESICCATION CRACKING 83 of study. There are many nonlinear processes involved in desiccation. As the soil dries, the formation of menisci causes very high negative water pressures (suction) to develop in the soil. The stiffness of the soil, which is characterized by parameters such as Young's modulus and shear modulus, increases with increasing suction. The resistance to cracking, i.e. the tensile strength or fracture toughness of the soil also changes upon drying. Finally, the adhesion at interfaces, which is essential in providing the restraint for desiccation cracks to form, changes with moisture content . The four phenomena mentioned above sometimes cause change of several orders in magnitude in material properties, making it virtually impossible for rigorous analytical solutions to be formed. Therefore, it is not totally surprising that, after many decades of research, published literature worldwide still focus on qualitative, semi-quantitative, and statistical analysis of crack patterns . Some studies analyse cracking without taking into account the changes in material properties. In the research reported herein, the distinct element code UDEC was used, along with the embedded programming language FISH to successfully model desiccation while capturing the nonlinear behaviour and considerable changes in properties while desiccation was in progress. The laboratory desiccation tests reported by Nahlawi and Kodikara [10] were used as a basis for validation and calibration of the model. The same methodology can be used to study field applications involving drying soil, as well as systems with time-varying properties in fields as diverse as paint, concrete, and pavement industries. * Tests 0-3 were carried out at 18 • C temperature and Tests 4 and 5 were carried out at 20 • C. † The dry density was computed at the start of the test. '-' indicates that dry density was not recorded, but it is considered to be similar to other tests owing to the same test procedure used.

Hazardous Air Pollutant (HAP) profiles from drying softwood and hardwood flakes (for the manufacture of oriented strand board) are very similar, indicating that they originate through a common mechanism, the breakdown of wood tissue. Hence, the strategies employed to reduce VOC (volatile organic compound) emissions from hardwood can also be extended to decreasing HAPs from softwood. Drying aspen flakes in the field and in the laboratory gives rise to different VOC species, and direct extension of laboratory data to the field may prove difficult. Formaldehyde emissions from drying fresh aspen flakes are lower than those from stored material; the opposite effect occurs for methanol and the other aldehydes. HAPs evolved from drying pine flakes surge sharply at 5-10% moisture content during drying at 130-160°C. Emissions of methanol, formaldehyde, pentanal, and hexanal all begin simultaneously, with the release of methanol and formaldehyde being the most sensitive to dryer temperature. Hence, the nature of the VOC mix is partly governed by the dryer temperature. Pine and aspen give rise to similar HAPs profiles during either drying or pressing flakes that are already dried.

Influence of Refractance Window™ Drying (RWD), a novel contact drying method, on carotenoids, capsaicinoids, Retinol Activity Equivalent (RAE) and Scoville Heat Unit (SHU) of paprika (Cv., Jalapeno) was investigated in comparison with freeze drying (FD), oven drying (OD), and natural convective drying (NCD) methods. Eight carotenoids (capsanthin, capsorubin, capsolutein, b-carotene, b-cryptoxanthin, mutatoxanthin, violaxanthin and zeaxanthin) and five capsaicinoid analogues (capsaicin, dihydrocapsaicin, homodihydrocapsaicin, isodihydrocapsaicin, nordihydrocapsaicin) were identified in paprika. All these components were significantly (P < 0.05) decreased by the RWD, FD and OD methods. However, due to ongoing synthesis, the NCD method resulted in higher carotenoids, except violaxanthin and mutatoxanthin, and capsaicinoids content than those of the others, even puree. Mutatoxanthin, naturally occurring pigment in red pepper, could only be detected in FD paprika. The highest RAE and SHU values, which were derived from the data of carotenoids and capsaicinoids, respectively, were also determined in NCD paprika.

The aim of this research was to model the drying kinetics of quinoa and to evaluate the temperature influence on the kinetic parameters of the models used. Prior to drying process, quinoa grains were washed at 60C and the removal of saponins was studied. Hot air drying temperatures were 40, 50, 60, 70 and 80C. Initial saponin content was 6.34%, reaching a final saponin content of 0.25% after 120 min of washing. Sorption isotherm was determined at 60C giving a monolayer moisture content of 0.051 g water/g dry matter. Drying kinetics was modeled with different equations. Diffusional coefficient increased with temperature from 3.78 to 7.67 ¥ 10 -11 m 2 /s, for a range of temperatures between 40 and 80C, with an estimated of E a 15.95 kJ/mol. According to the statistical tests used, the logarithmic and Weibull models gave the best fit for experimental data (determination coefficient > 0.98, sum squared error < 0.001 and Chi-square < 0.001).

Changes in fluidization behaviour of green peas particulates with change in moisture content during drying were investigated using a fluidized bed dryer. All drying experiments were conducted at 50 + 2 0C and 13 + 2 % RH using a heat pump dehumidifier system. Fluidization experiments were undertaken for the bedheights of 100, 80, 60 and 40 mm and at 10 moisture content levels.

Sunflower is an important crop in Argentina. To prevent field losses caused by unfavorable environmental conditions, there is a tendency to early crop of grains at higher levels of moisture than the level of safe storage, and then drying is essential to conserve the product. The available information in bibliography about the Sunflower grain drying characteristics is relatively small. In the present work Fick's law was used to simulate the drying kinetics in thin layer of sunflower grain. This theory has been widelv used in the bibliography to simulate the drying in thin layer of agricultural crops, wi/h diverse suppositions. The objective of this investigation was to determine the difusivities of water in the two basic components of sunflower grain, the pericarp and the endosperm. The endosperm and whole grain drying kinetics was determined experimentally at 40°C. and 50°C with an air speed of 15 m/s. Using the solutions that better adjust to the data, it was found that the difusivities of the endosperm are 7.1 * 10 -1 1 m 2 /s and 1.7 * 10 -1 0 m 2 /s, and the difusivities of the pericarp are respectively 1.7 * 10 -1 0 m 2 /s and 7.1 * 10 -1 0 m 2 /s for temperatures of 40°C. and 50°C, respectively.

Modelling of food processing is complex because it involves sophisticated material and transport phenomena. Most of the agricultural products such fruits and vegetables are hygroscopic porous media containing free water, bound water, gas and solid matrix. Considering all phase in modelling is still not developed. In this article, a comprehensive porous media model for drying has been developed considering bound water, free water separately, as well as water vapour and air. Free water transport was considered as diffusion, pressure driven and evaporation. Bound water assumed to be converted to free water due to concentration difference and also can diffuse. Binary diffusion between water vapour and air was considered. Since, the model is fundamental physics based it can be applied to any drying applications and other food processing where heat and mass transfer takes place in porous media with significant evaporation and other phase change.

The increasing tendency to enhance consumer products with added functionality is leading to ever more complex products. Nowadays more and more particulate products are coated to give the product specific functionalities. An appropriate approach is needed to be able to satisfy customer's requirements. In this work, three reference well-known coating agents, namely two grades of hydroxypropyl methylcellulose (HPMC) and one polyvinyl alcohol (PVA) were selected and investigated. Aqueous solutions of such polymers were obtained and viscosity and shear stress were measured function of shear rate, temperature and polymer concentration. The viscosities of the solutions appear to be mainly shear rate independent, they clearly show Newtonian behaviour. Drying and storage conditions influence on morphology and structure of the cast films were evaluated using scanning electron microscope (SEM). Dynamic mechanical thermal analysis (DMTA) experiments were carried out on HPMC and PVA cast films to assess the viscoelastic properties over wide temperature-frequency range. The time-temperature superposition principle was used to determine the shift factor, a T , and to compose a master curve. Magnitudes and profiles of storage modulus, E , loss modulus, E , and tan ı master curves are discussed with relation to drying and storage conditions. No impact of drying temperature on the polymer properties was observed whereas the effect of storage temperature resulted to be relevant in terms of shifts in glass transition temperature and, only partially, changes in the magnitudes of E and E .

BACKGROUND: Sea algae cellulose has been little utilized because the cellulose content in sea algae is low. For the effective utilization of sea algae cellulose, cellulose must be converted without drying into valuable material with a high rate and yield. From this viewpoint, effects of hydrothermal pretreatments of sea algae to enhance the glucose production by enzymatic hydrolysis of sea algae cellulose were investigated. RESULTS: Using hydrothermal pretreatment performed at 423 K for Monostroma nitidum Wittrock (green alga) and at 473 K for Solieria pacifica (red alga) for 30 min, yields of extracted water-soluble components containing monosaccharides were 0.51 g g −1 for the green alga and 0.62 g g −1 for the red alga. The apparent rate of glucose production from hydrothermally pretreated green alga by enzymatic hydrolysis was >10 times faster than that of the non-pretreated sample. Yields of glucose from cellulose by enzymatic hydrolysis were 79.9% for the green alga and 87.8% for the red alga.

In this study, intermittent drying behavior of single layer rough rice with a moisture content of between 22 and 24% on the dry basis was simulated by means of a liquid diffusion model based on a prolate spheroid geometry. For this purpose, solution of the liquid diffusion equation was fitted to the experimental data for the drying air temperature 40°C, drying velocity 1.5 ms−1 and tempering periods ranging from 0 to 1 h. In order to make a comparison, solution of the liquid diffusion equation for a finite cylindrical geometry was also fitted to the experimental data. The results show that the liquid diffusion model based on a prolate spheroid geometry explains the drying behavior of rough rice more accurately. The results also show that greater variations occur in diffusion coefficient with increasing tempering time for prolate spheroid geometry which is more realistic geometry for a rough rice grain.

Computational fluid dynamics (CFD) modelling with the Eularian -Eularian formulation is used to describe the drying phenomena occurring in pneumatic conveying drying particularly in the U-bend. Two user defined scalar equations (UDSs) are inserted into the solution to take into account the solid particle moisture content and the mass fraction of water in the gas phase, respectively. The drying kinetics cover the two periods of drying: the constant drying rate and the falling drying rate. The investigation emphasized influences of the parameters (solid loading ratio, gas velocity, bend radius ratio, feed moisture content and geometry arrangement of a U-bend) on the drying rate and moisture content. A validation of the drying model is accomplished by comparing calculation results with experimental data. In general, the drying rate decreases along the axial direction of pipe due to the decrease in driving force (the air humidity increases). The mass-weighted average drying rate shows a slight decrease in and just after the U-bend, which is mainly due to the high accumulation of solid particles at the outer U-bend wall. Solid particles disperse and the slip velocities are high in the area after the U-bend. This causes the mass-weighted average drying rate to slightly increase.

Sonochemical synthesis followed by supercritical drying was used to prepare MgO nanoparticles from Mg(OCH 3 ) 2 and Mg(OC 2 H 5 ) 2 . Their physicochemical properties were examined by means of X-ray diffraction (XRD), simultaneous thermal analysis (DTA, TG, EGA), specific surface area measurement, scanning and transmission electron microscopy. The dehydrated MgO oxides were free of -OCH 3 groups. The highest values of specific surface area (1236 m 2 g À 1 ) have been obtained by hydrolysis of magnesium methoxide using toluene as solvent agent. D

In this paper, we deal with development of a new analytical model for predicting drying times of irregular shaped multi-dimensional moist solids. Irregular products are approximated by representative elliptical cylinder and ellipsoid for two-and three-dimensional shapes, respectively. Using the experimental drying parameters that are available from the literature, drying times of irregular, multi-dimensional products are determined through the present models. In this regard, geometric shape factors for elliptic cylinder and ellipsoid are employed and based on the reference drying time for an infinite slab geometry. In addition, the present models are verified through comparison with experimental drying times of several food products. The accuracy of the predictions using the present models is then discussed.

A new approach for the estimation of apparent thermal diffusivity of foods at different drying temperatures was explored, analysed and discussed in this work. Temperature versus time was obtained numerically at the center of the food (banana, ''nanicão" variety) using the 1D Fourier equation with drying temperatures in the range between approximately 17-65°C and moisture content in the range between 0.01 and 3.43 (dry basis). The solution of the partial differential equation is made with a finite difference method coupled to an optimization technique of Differential Evolution used in inverse method. The mathematical model proposed considered the effects of shrinkage and convective heat transfer at surface of fruit. Parameters of two functions, the first dependent of the moisture content and the second dependent also of the temperature were obtained by inverse method modelling the apparent thermal diffusivity. Such parameters that provide the best least square fit between the experimental and predicted time-temperatures curves are presented in this work. This study demonstrated that a small change in the temperature and moisture content of banana cause an abrupt change in the apparent thermal diffusivity, which decrease with the decreasing of the moisture. Statistical analysis shows the excellent agreement between reported and estimated curves.

The collection efficiency of a fiber filter of polyester operating in the removal of nano-sized aerosols was studied here. The polyester filter utilized had 0.882 in porosity, 4.5 mm in thickness, and fiber mean diameter of 16.0 m. A TSI Electrospray Aerosol Generator, model 3480, was used to generate monodispersed nanometric particles, with sizes varying from 8.5 to 94.8 nm. The nanoparticles were generated from solutions of NaCl which were atomized as droplets, followed by drying. The filtration device was built in acrylic with a filtration area of 0.4 m 2 . The filter efficiencies were obtained by counting the particles before and after the filter, using a TSI Condensation Particle Counter, model 3007. The tests were accomplished at gas superficial velocities varying from 0.03 to 0.25 m/s. The results show the efficiency decreasing with increasing particle size, indicating the predominance of the diffusional mechanism in the range studied. Also, the filter efficiency decreased with filtration velocity. The results were compared to well known theoretical predictions based on the classical collection mechanisms: diffusional and direct interception. The comparison of the calculated collector efficiency with the experimental results showed that the predictions underestimate the results. A correction was proposed to the existing correlation for direct interception, where an 'effective' diameter accounting for the Brownian motion of the particle while in the vicinity of the collector surface was accounted for. The proposed modification included no fitting parameter. The results showed a considerable improvement in the prediction correlation.

In this study, the influence of air temperature, velocity and humidity on the thin-layer drying of rosehip was investigated. A laboratory air drier was designed and used for drying experiments. The system was operated in an air temperature range of 50-801C, air velocity range of 1Á67-3Á10 m s À1 and air absolute humidity range of 0Á005-0Á08 kg [vapour] kg À1 [dry air]. Six mathematical models available in the literature were fitted to the experimental data. By statistical comparison of the values for the six models, it was concluded that the logarithmic model represents drying characteristics better than the other equations.

This paper presents a study on the mathematical modelling of bay (Laurus nobilis L.) leaves. Drying experiments were performed in a laboratory scale dryer constructed in the Department of Agricultural Machinery, Faculty of Agriculture, Ege University, Izmir, Turkey. The leaves were 90-100 mm long and 30-40 mm wide, and ones with no blemish were selected and used for the drying tests. The tests were performed with various relative humidities (5%, 15% and 25%) and temperatures (40, 50 and 60°C) at a constant air velocity of 1.5 m/s. Fifteen different mathematical drying models were compared based on their correlation coefficient, root mean square error, mean bias error, reduced chi-square and t-statistic method to estimate the drying curves. It may be concluded that the Page model could sufficiently describe drying of bay leaves.

The citrus by-products (CBP) released from the citrus processing plants may contain high amount of potential bioactive compounds. Hence, this study aims to evaluate the antioxidant activity of CBP prepared using a novel drying technique known as high speed drying (HSD), economically and efficiently. HSD extract showed high amount of polymethoxylated flavones (heptamethoxyflavone and nobiletin) and flavanone (hesperidin and naritutin). The antioxidant activity was evaluated by means of DPPH, hydroxyl and alkyl radical scavenging assays and lipid peroxidation assay. HSD extract showed strong activities on radical scavenging (IC 50 value of DPPH, hydroxyl and alkyl radicals scavenging were 0.16, 0.5, 0.019 mg/mL, respectively) and lipid peroxidation inhibition. These results suggest that the flavonoids and other phenolic compounds in the HSD extract could be good radical scavengers. Hence, HSD method is an effective and efficient method to transform citrus by-products into dried form and could be used in food and pharmaceutical industry as a natural antioxidant agent.

The IDS (Incubation, Drying and Separation) method was tested on Schinus molle L. seeds collected from Ethiopia in an attempt to sort non-viable from viable seeds. Seeds were incubated for 24 h followed by one, three, four, five, six, nine and twelve hours of drying and then separated in water. All IDS treatments gave 80.5–93.5% germination in the sunken fraction compared with 61% for untreated seeds. The mean germination time of sunken seeds reduced from 11.2 (control) to 8.9–9.2 days (IDS-treated). Specific gravity separation in water of untreated seeds was also tested, and the germination capacity of sunken fraction was 83.5% with a mean germination time of 9.3 days. IDS method can, therefore, be used to enhance both percentage and rate of germination of a seed lot of Schinus molle, which is desirable to produce uniform and vigorous seedlings in the nursery or out in the field.

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.

Combined far-infrared radiation with hot-air convection (FIR-HA) drying was used for improving colour and antioxidant properties of mulberry leaf tea. Antioxidant properties and phenolic compounds of FIR-HA dried mulberry tea were determined and compared with the commercial product and with fresh leaves. We found that a smaller decrease in L and b values of the FIR-HA dried tea than those of commercial tea was observed. FIR-HA tea was found to have similar colour to fresh leaf while the commercial tea had darker colour. A significant decrease in total phenolic acid content (TPC) and total flavonoid content (TFC) was found in hot-air (HA) dried commercial tea compared to fresh leaves, while TPC in FIR-HA dried tea was significantly increased. Similar results were found in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical activities. However, the results were different for ferric reducing antioxidant power (FRAP). Both teas had lower FRAP values compared to fresh leaves. Eleven phenolic compounds were identified in fresh leaf and in mulberry tea, namely p-coumaric acid, benzoic acid, (+)-catechin, chlorogenic acid, vanillic acid, syringic acid, sinapic acid, protocatechuic acid, ferulic acid, gallic acid and caffeic acid. The total content of phenolic compounds (TPCC) increased in FIR-HA dried samples compared to those of HA dried tea, except for chlorogenic and syringic acids, which were found in greater amounts in HA dried commercial tea. Our results have demonstrated that FIR-HA should be considered as a suitable drying method for mulberry tea with respect to preserving its antioxidant properties and phenolic compounds.

By means of a slow drying process and the control of surface charge characteristics, protein stripe patterns were readily prepared on the luminal surface of a capillary. We systematically studied the effects of surface properties, pH, and protein concentration on pattern formation using optical microscopy, atomic force microscopy, and quartz crystal microbalance measurement. By balancing these parameters, a broad selection of proteins could be assembled within a capillary with well-defined stripe patterns. Neutravidin, one of the model proteins, was specifically chosen to demonstrate the bioactivity retained through the assembly process by interaction with fluorescently labeled biotin motifs. This technique therefore offers a facile approach for patterning proteins and other biomacromolecules in capillary tubes.

Fresh persimmons were subjected to two different processes: sun-drying during 1 month and dehydration at 60 1C during 12 h. To assess the effect of this process on nutritional and health-related properties of persimmons dietary fibers, minerals, trace elements, polyphenols and the total radical scavenging activities (TRSAs) were determined before and after processing. It was found that the contents of dietary fibers, minerals and trace elements in fresh and dried persimmons fruits were comparable. Total polyphenols in fresh persimmons was higher than in dried fruits (1.3 vs. 0.9 and 0.8 mg/100 g FW, respectively) and percentage of inhibition was higher than in dried fruits (70% vs. 59% and 55% and 58% vs. 53% and 46% for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2 0 -azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) [ABTS] radicals, respectively (P40.05 in all cases). In conclusion: (1) the differences in the contents of dietary fibers, minerals and trace elements in fresh and dried persimmons are not significant; (2) the contents of polyphenols and the level of the TRSA are higher in fresh persimmons than in dried fruits; however, both variables are also high in dried persimmons; (3) when fresh fruits are not available, proper dried persimmons could be used as a valuable substitute.

We present a numerical simulation of the functioning of a wood solar dryer in atmospheric conditions of Moroccan climate. A comparison of our numerical results with experimental measurements carried out on a wood solar dryer shows a good agreement. Results show that drying period is closely linked to glass partitions and timber thickness. The type of ventilation has no effect on the drying period (initial timber humidity lower than 40%). The substitution of east and west glass faces by concrete walls has practically no effect on drying period. r

In this work a drying system was constructed, consisting of three parts (solar collector, solar drying cabinent, and air blower). Two identical air solar collectors having V-corrugated absorption plates of two air passes, a single glass cover was used. The total area of the collectors is 2.4 m 2. The dimensions of the drying cabinet are 1 × 0.33 × 2 m (width, depth, and height). The cabinet is divided into six divisions separated by five shelves. The distance between the shelves is 0.3 m except the upper one, which is 0.5 m from the roof. Each shelf is 0.95 × 0.3 m and is made of metallic mesh. The drying chamber walls are made of aluminum plate except the southern side, which was fixed with glass plate having the dimensions 1 × 2 × 0.002 m. Two types of fruit and one type of vegetables were dried during the present work. These were grapes, apricots, and beans. The moisture content of apricot was reduced from 80 to 13% within one day and a half of drying. Moisture content of grapes was reduced from 80 to 18% in two and a half days of drying, while that of beans was reduced from 65 to 18% in one day only. The results show that the most effective factor on the drying rate is the temperature of the air inside the cabinet. The effect variation of speed of air inside the drying cabinet is small and can be neglected. The relative humidity of air exit from the cabinet was small between (25-30%) and therefore there is no need for high velocity air inside the cabinet.

An increase of peroxidase activity in the seeds of cocoa (Theobroma cacao L.) during their ripening has been determined. An additional increase of the peroxidase activity (about 10 times) is observed during the fermentation and drying of the beans. The residual activity determined in the cocoa beans after sun-drying was higher than that in unfermented ripe seeds. The major cocoa isoperoxidase was shown to be an acidic enzyme with pI 4.7. Using isoelectrofocusing, the appearance of two basic isoenzymes of the peroxidase with pI 8.6 and 9.0 during the process of the fermentation has been detected. #

Altarpieces and polychrome carved wood from the fifteenth century AD usually exhibit golden and silvery areas by the application of a very thin foil of metal. The metal foils were normally protected from the atmosphere by a varnish or resin which maybe either preserved or absent. Moreover, they were glued to the background surface by adhesive substances (egg yolk, drying oil or animal glue). The high proportion of the glueing substances often renders the development of reaction compounds. With time, silver alters blacken or simply disappear completely. In this paper, we study the alterations to metal foils from a selection of fifteenth century artworks showing different glueing agents, organic coatings and several degrees of conservation of the organic coatings and metal leafs. The submillimetric layered structure and the high variability and low amount of most of the compounds present in the different layers, as well as their differing nature (organic and inorganic) make the use of micron-sensitive highresolution techniques essential for their study. In particular, the high resolution, high brilliance and small footprint renders synchrotron radiation most adequate for their study. SR-XRD was performed to identify the reaction compounds formed in the different layers; μFTIR was used at to identify the silver protecting organic coatings, the metal foil glueing layers and the corresponding reaction compounds. The results obtained suggest that atmospheric corrosion is the dominant mechanism, and therefore that the degree of corrosion of the metal foils is mainly related to the conservation state of the protecting coatings.

Apple cylinders (Granny Smith) were dried in a combined hot air-microwave system. Drying experiments were carried out at various air temperatures (25, 30, 40 and 50°C) combined with different levels of microwave incident power (0, 3, 5, 7 and 10 W/g) until 0.11 (d.b.) moisture content was obtained. Vacuum impregnation with an isotonic solution was used as a pretreatment before drying. Sample weight changes were determined for different drying conditions. When drying with combined air-microwave system, the drying rate curve could be divided in four periods limited by four critical points. An empirical model was proposed to estimate the drying kinetic constants as a function of the air temperature and the microwave power level for both sorts of samples, fresh apples and impregnated apples. At the end of the process different tissue matrices were obtained depending on the different drying conditions.

Flexible aerogel-glass fiber composites were prepared by varying colloidal silica and tetraethylorthosilicate (TEOS)-based sol fractions. After immersing glass fiber matrices into silica sol with different volume fraction of colloidal silica sol, it was surface-modified into trimethylchlorosilane/n-hexane solution and heat-treated at 230 • C in ambient atmosphere. From the results of Brunauer-Emmett-Teller (BET) surface area, Barrett-Joyner-Halenda (BJH) pore size analyses, apparent density and porosity studies, it was thought that microstructures of aerogel composites like pore size and specific surface area were greatly affected by precursor sol. Aerogel composites made of only colloidal silica showed greater density and lesser porosity, smaller pore size and specific surface area than those of aerogel composites synthesized from colloidal and TEOS-based mixed sols.

Bitter gourd (Momordica charantia), a seasonal vegetable is a source of many essential nutrient and contain low energetic and anti-diabetic property. To increase the self-life, a drying operation was done by using hot air oven dryer at different thickness of fruit slice (3,6 and 9mm) and temperature (60 ,70 and 80°C). The sliced bitter gourds were treated by NaCl solution before drying and dried up to 5 per cent moisture content (MC) on dry basis (db) and grinded to powder for further experiment. The drying rate increases with increase of temperature and decrease of thickness whereas diffusion and activation energy increase with increase of temperature and thickness and they are significantly variable. The maximum value of diffusion coefficient, activation energy, ascorbic acid and the protein were found at 80°C and 9mm thickness (1.9149×10-9 (m 2 s-1), 118.77 KJ kg-mol-1 , 77.65 mg100g-1 and 5.65% (d.b.)) and minimum at 60°C and 3mm (0.0085×10-9 (m 2 s-1), 74.93 KJ kg-mol-1 , 17.65 mg 100g-1 and 3.77% (d.b.)). Losses of nutrients were non-significantly variable.