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Active Pharmaceutical Ingredients (APIs) are often present in more than one polymorphic form. Most of the time one of these polymorphs has better properties than others and is the desired form. How...

Tomatoes are a valuable highly perishable agricultural product that are dried on a large scale for extending shelf life. The drying of both tomatoes and tomato processing waste can yield valuable p...

The basic design of most commonly used solar dryers displaying varying fundamental principles of heat and mass transfer were compared with recently commercialized and patented design of Solar Condu...

Open sun drying has been used for many years for grain drying. Unfortunately, in open sun drying, solar energy is improperly utilized, and it takes a longer time to dry, leading to a compromise in ...

Solar conduction dryer is a unique technology that uses conduction, convection, and radiation mechanism of heat transfer, making it one of the most efficient drying systems. Quantitative analysis s...

Vaccines are the most important life-saving prophylactic medicines administered in maintaining global health. In a pandemic situation, the manufacturing, formulation followed by preservation of vac...

This study explores the impact of a house-hold, post-harvest processing unit on the nutritional, economic, and social status of rural women. Solar Conduction Dryer (SCD) is an electricity-free, solar-powered food dehydrator for the production of dried vegetables, fruits, marine, and meat-based products. SCD was provided to 200 rural women farmers in the Aurangabad district of India. The availability of the dryer enabled the women to preserve seasonal produce during the surplus season and consume it during the lean period. An increase of 36% in the Women's Dietary Diversity Score was observed in the intervention group as compared to the control group in the lean season, indicating increased food accessibility and availability. Providing the appropriate market linkage and initial hand-holding helped the women to earn additional income through the sale of the dehydrated products. This research explores the sustainability of the said technological intervention and its role in agri-nutrition linkage.

Solar drying is one of the most beneficial and sustainable technologies benevolent to our society. In this paper, comprehensive review of various designs of natural convective and direct type (NCDT...

Scientific and technical literature in drying has seen exponential growth in the last three decades. Much of this resulted from the establishment of the widely acclaimed biennial International Dryi...

Coke breeze briquettes are promising low-cost substitute to metallurgical coke, prepared by adding binder to the coke breeze to form briquettes. At present, pregelatinized starch is used as binder ...

In the present study, certain quality parameters of raw and traditionally sun-dried (TSD) Bombay duck samples are compared with dried fish samples obtained from hot air dryer (HAD), freeze dryer, and a newly developed and patented solar conduction dryer (SCD). The parameters analyzed are total viable count, total fungal count, total volatile nitrogen, and trimethylamine (TMA) content and color. It is found that the experimentally dried fish have better microbial and biochemical quality as compared to TSD fish. This study addresses the issue of unhygienic open sun drying and handling of dried products and the need to adopt use of dryers based on the recently developed appropriate drying technology such as SCD which is expected to be transformed into sustainable technology.

Mechanical cake dewatering is always desired to reduce the load on thermal dewatering (drying). Any change in the upstream process such as crystallization can have a significant influence on the filtration as well as cake dewatering characteristics. The present study deals with the effect of hydrodynamics (mixing intensity) during salicylic acid crystallization on the air dewatering characteristics in the subsequent pressure filtration. The mixing conditions during crystallization were varied by using three different types of agitators (anchor impeller [AI], curved blade turbine [CBT], and bar turbine [BT]) and by varying the speed of agitation. The effect of operating pressure and dewatering time on the final moisture content of the cake was also studied. The crystal properties (crystal size and size distribution) were found to vary with the mixing intensity, which further influenced the cake dewatering kinetics as well as the residual moisture content. An AI, which is a laminar flow impeller, produced c...

Liposomes are widely used in the pharmaceutical, biopharmaceutical, cosmetic, and nutraceutical sectors as an efficacious drug-delivery system for improving the bioavailability and protection of the entrapped drug molecule. The present study evaluates freeze-thaw as a simple approach for screening the most appropriate lyoprotectant. The freeze-thaw study is based on the principle that an excipient, which protects liposomes during the first step of freezing, is likely to be an effective lyoprotectant. Curcumin liposomes with high entrapment efficiency were prepared using a lipid film hydration technique. The freeze-thawing study was carried out using various lyoprotectants such as sucrose, mannitol, lactose, dextrose, and maltose. Sucrose showed minimal particle size change with better cryoprotection after the freeze-thaw study. The internal and external addition of sucrose during formulation has shown significant effects on the retention of particle size and curcumin content during the freeze-thawing and ...

Value addition to several agri-products such as grains, beans, and millets can be achieved by sprouting followed by thermal treatment. These value-added products can then be suitably formulated and fortified using cost-effective technologies so that they may be used as instant food, weaning food for babies, or functional food. Finger millets, used extensively by Asian and African communities, were studied. Sprouted finger millets were blanched (using hot water and steam) and dried using a fluidized bed dryer. This led to quality enhancement in terms of higher protein content, digestibility, and bioavailable micronutrients. The drying of sprouted millets (ragi in this case) over the temperature range of 40–70°C was studied. Later, the effect of infrared and pan roasting was studied to determine its effect on protein content and other sensory parameters. Dehydrated sprouted finger millets flour can be used for making noodles, papads, unleavened bread, and several other Indian cuisines such as idli, chakli, ...

Separation and purification of phosphatidylcholine (PC) and phosphatidylinositol (PI) fractions to their utmost purity is still a challenging task industrially due to the molecular and structural complexity of lecithin molecules. The present study deals with the filtration of the PI-rich fraction followed by drying of the cake for its further purification and value addition. Filtration of the PI-rich fraction was carried out under constant pressure conditions followed by the drying of the cake in a vacuum tray dryer. The average specific cake resistance (αav) as a function of operating pressure was studied and it showed little variation with respect to the applied pressure differential. The initial solvent content in the cake after filtration was found to be in the vicinity of 1 kg solvent/kg dry solid, which was then subsequently reduced in the drying stage to 0.04 kg solvent/kg dry solid. The drying kinetics of the cake was studied at different drying temperatures in a vacuum tray dryer operated under v...

Garlic (Allium sativum) has been cultivated for centuries all over the world on account of its culinary and medicinal properties. The present work has been carried out with the emphasis on selection of an efficient and cost-effective drying technique for garlic with highest allicin retention. For comparative study, drying of garlic samples were experimented with using different methods, namely heat pump dryer, hot air dryer, solar cabinet dryer, infra red dryer, vacuum dryer, freeze dryer, and fluidized bed dryer having different operating conditions. A comparison of the efficiency of various drying methods was based on the parameters, e.g., drying kinetics, allicin content, and color analysis. In addition, the effect of garlic slice thickness on the above-mentioned parameters was also studied. Drying of garlic shows a typical falling rate period in sliced form. It was observed that dried garlic samples using heat pump drying, vacuum drying, freeze drying, and heat pump cum fluidized bed drying showed les...

This work deals with formulation and drying of a newly developed functional food. A watermelon and carrot juice mixture in the ratio 70:30 by volume was fermented at 37°C with Lactobacillus acidophilus to produce an innovative non-dairy-based food formulation with good flavor and high nutritional value. Viable count, pH, titrable acidity, protein content, and reducing sugar were measured during fermentation. The probiotic juice was spray dried at air temperature of 120 to 160°C and flow rate of 2.0 to 5.0 mL/min. Maltodextrin concentration of 10 to 15% by weight was used as an additive. Response surface methodology (RSM) was employed to optimize the drying process conditions. Physical properties (e.g., moisture content, density, porosity, and yield), biological properties (e.g., viability and lycopene and beta carotene content), and solubility data were examined as the response variables. Elevated temperatures and longer exposure times at lower feed rate reduced viability and lycopene and beta carotene co...

The drying of micrometer-sized, cohesive particles belonging to the group C type materials according to Geldart's classification is always challenging. An agitated fluid bed dryer (AFBD) of pilot-scale capacity was designed to study the effect of the type of agitator and its speed, gas velocity, and inlet temperature and feed loading on the hydrodynamic performance of the AFBD. Key hydrodynamic parameters such as pressure drop have a profound influence on determining the fluidization characteristics. The pressure drop across the AFBD system was expressed in terms of flow coefficient, ξ, which can be conveniently used as a design parameter. The choice of agitator has an even greater influence on the drying kinetics and the results have been summarized, paving the way for a more efficient spiral agitator of the helical ribbon type.

Saccharomyces boulardii yeast is considered as a probiotic according to the World Health Organization (WHO). Like any other probiotic, Saccharomyces boulardii is available as a freeze-dried formulation. Although freeze drying is the most preferred method of preserving the microorganisms, the process is very expensive. The cost of capsules containing freeze-dried probiotic yeast is certainly out of reach of the underprivileged population of the world. Hence, the present work focuses on developing a new formulation and cost-effective drying process for probiotic yeast. Freeze drying was compared with fluidized bed drying (FBD) and heat pump–assisted fluidized bed drying (HP-FBD) techniques for drying of Saccharomyces boulardii formulation. The process involves addition of lactose and microcrystalline cellulose to the biomass obtained by centrifugation and then making the dough. This blend is then extruded and spheronized to form granules. Heat pump fluidized bed drying of the formulation resulted in higher ...

Agitated thin-film dryers (ATFDs) are used to produce dry free-flowing powder from slurry/solution-type feed and widely implemented in pharmaceutical, chemical, and food industries. The feed passes...

Generally used as an inexpensive source of high-quality protein with many other health-promoting properties, soy milk offers an interesting alternative when fermented. Fermentation with lactic acid bacteria brings about the value addition to soy milk, making a nutritious probiotic food product. Dehydration helps to achieve longer shelf life and easier transportation and storage, enabling wider distribution of the product. The present work pertains to optimization of process parameters for spray drying of fermented soy milk using response surface methodology (RSM). The process parameters studied include inlet air temperature, aspirator speed (air flow rate), feed flow rate, and atomization pressure. The experiments were designed using the central composite design tool. Residual moisture content was found to be low at higher inlet air temperature, lower feed flow rate, higher atomization pressure, and higher air flow rate. Porosity reduced with increased atomization pressure. Higher product yield was obtain...

Ginger (Zingiber oficinale) has many applications in the food and pharmaceutical sectors as an additive in a number of commercial foods and beverages. It is valued both for its aromatic volatile constituents and its spicy, pungent constituents. Ginger, if taken in a proper dosage, has high medicinal value because it is useful in preventing motion sickness and has a calming effect on upset stomach. Dehydration helps to achieve longer shelf life and easier transportation and storage, enabling wider distribution of the product. But it is important to retain the 6-gingerol, the active component, during drying of ginger extract. The present work pertains to the optimization of spray drying of ginger extract using response surface methodology (RSM). A central composite method was used to design the experiments. Different parameters investigated include inlet temperature (120–160°C), air flow rate (40–60 Nm3/h), feed rate (2.5–4 mL/min), and atomization pressure (1.5–2.25 kg/cm2). Optimum drying conditions for s...

Soymilk has attracted much interest in the food industry because of its health- promoting properties. Fermentation with lactic acid bacteria is known to provide value addition to soymilk by reducing the beany flavor and content of indigestible oligosaccharides and by enhancing the bioavailability of isoflavones, resulting in a nutritious probiotic food product. In the present study, Soymilk fermentation was studied using Lactobacillus acidophilus strain isolated from ragi, and effect of soymilk supplementation on the fermentation characteristics was also investigated. Viable count of 1.99 × 109 CFU/mL sample and 630.1 U/g of β-glucosidase activity were determined in soymilk after 12 h of fermentation. Soymilk supplementation with skimmed milk powder at 5% level gave best results with viable counts of 22.9 × 109 CFU/ml sample or 212.9 × 109 CFU/g solids; 764 U/g of β-glucosidase activity, 1.44% la titratable acidity and pH of 3.9. Daidzein and genistein profile in fermented soymilk showed that 45.8% and 57...

The present work reveals the preparation of waterborne acrylic emulsion for interior coating. The emulsion was prepared by sequential core-shell polymerization method. The prepared acrylic emulsions were then spray dried and converted into redispersible powder. The effect of different neutralizing agents on the powder transformation yield and redispersibility properties of the polymer powder was studied. The mother emulsion and redispersible emulsion showed similar flexibility, impact resistance, and adhesion property. In addition, this article describes the preparation of redispersible aid by solution polymerization of acrylic acid–methyl methacrylate. The resultant spray-dried powder showed very good redispersibility.

Response surface methodology was used to optimize the pretreatment prior to solar cabinet drying (SCD) of green peas. Thirteen experiments were conducted using a central composite design (CCD) with two variables at two levels each, viz. blanching time (1–5 min) and potassium metabisulphite (KMS) concentration (0.2–0.5%). Solar cabinet drying of pretreated green peas was carried out up to 6% (d.b) moisture content. During drying the air temperature, relative humidity, and air velocity in the dryer were in the range 40–60°C, 40–50%, and 0.9–1 m/s, respectively. After drying, color (a value) and hardness (g) of the dehydrated green peas were measured and taken as responses. During optimization, the best process conditions were found with 4.24-min blanching time and 0.49% KMS concentration resulting into −7.86 color (a value) and 548 g hardness. Green peas were dried in solar cabinet dryer using the pretreatment at optimum conditions and some selected quality parameters like color (a value), hardness, rehydra...

Drying of tomato slices was carried out using five different methods, viz., hot air (HAD), solar cabinet (SCD), heat pump (HPD), microwave vacuum (MVD), and freeze drying (FD). During drying by hot air, solar cabinet, and heat pump drying only falling rate periods were observed, whereas microwave vacuum and freeze-drying processes showed both the constant and falling rate periods. The Page model constant, moisture diffusivity, and Peleg model constants were estimated to compare the dehydration and rehydration kinetics. During microwave vacuum drying of tomato the highest values of Page model rate constant and moisture diffusivity were obtained, whereas freeze drying resulted in lowest values. During rehydration studies, heat pump and microwave vacuum–dried tomato slices showed comparatively higher rehydration ratios than hot air– and solar cabinet–dried slices, whereas freeze-dried samples showed the highest rehydration ratio. Also, Peleg model constants were estimated.

Nanoparticles were prepared by using an emulsion solvent evaporation method. Further, the drying of an anti-cancer drug of proprietary nature (nanosized) was carried out by a freeze-drying technique to get a free-flowing powder. A systematic approach was developed to study the freeze-drying technique for polymeric nanoparticles. Initially, the freeze-thawing experiments were carried out with varying concentrations of cryoprotectants to screen the most suitable cryoprotectant. Subsequently, the freeze drying was carried out with the selected cryoprotectants to study their effect on the final product quality after drying. Annealing experiments were carried out to optimize the freeze-drying cycle time and study its effect on the particle size of nanoparticles. The effect of selected cryoprotectant on the heat and mass transfer parameters was also studied. Finally, the simulation of the freezing temperature was carried out by using MATLAB 7.0 software. The lyophilized product was characterized in terms of app...

Maize starch (Zea mays) was gelatinized and dried using a jacketed single-screw extruder. The degree of gelatinization (DG), color, swelling properties, solubility, apparent and true densities, expansion ratio, and porosity of extruded maize starch were analyzed. The effects of temperature, feed moisture content, screw speed, and feed rate on the extrusion process and final product properties were also studied. The apparent density of the extruded product was found to increase with an increase in the feed moisture content and residence time, whereas it decreased with an increase in the extrusion temperature. It was observed that the porosity and expansion ratio of the extruded product decreased significantly with increased feed moisture content and residence time. In addition, an increase in temperature led to a product of higher porosity and expansion ratio. Also, the degree of gelatinization increased with an increase in the temperature and screw speed. A correlation was developed for the throughput and...

The drying of organic pigments is a challenging assignment due to the complex relationship between heat and mass transfer and the quality attributes such as color, shade, and strength. There is an urgent need to address the drying technology-related issues of this industrially important class of specialty chemicals. The widely used tray dryers and band dryers need further attention due to abysmally low energy efficiency. One of the ways to overcome the longer drying time is to make use of infrared source in addition to convective air drying. The present article discusses the effect of combinatorial IR-convective drying on the quality aspect of organic pigments. The heat and mass transfer rates were analyzed in terms of Biot number to ascertain the role of infrared in bringing down the drying time without compromising the pigment qualities. The mathematical analysis of drying of preformed pellet of pigments was carried out in terms of effective diffusivity, which was obtained in the range of 10−9 to 10−10 ...

Sapota (Achras zapota) is a tropical fruit found in several parts of India. It is one of the most popular fruits besides mango, custard apple, and several others. Once ripe, it needs to be consumed within a couple of days due to the highly perishable nature of this exquisite fruit variety. The best way to increase the shelf-life is through the process of dehydration of peeled sapota. In the present study, the convective air drying of sapota pulp was carried out and compared with low-temperature drying techniques such as heat pump–assisted drying and freeze drying. The sapota paste was dried in a convective dryer to study the effect of operating parameters such as air temperature and air velocity. In addition, the effect of additives such as oat and wheat fibers and the paste thickness on drying was also studied. The critical analysis of dehydrated sapota was carried out in terms of water activity, sugar content, color, and rehydration ratio. The drying data were analyzed using Page's model and Newton's mo...

The extensive use of chemicals in agriculture, in particular herbicides, is a serious environmental concern. There is an urgent need to develop smart herbicide formulations that combine both optimum bioactivity and minimum dosages. In the current article, an attempt has been made to design the formulation based on one of the most widely used herbicide, Atrazine (AT). This potent herbicide along with “China clay” as the carrier and suitable clay modifiers can be thought as one of the potential way of formulation keeping in view the desired dosage and bioavailability of the same. The China clay was subjected to modification using a surfactant blend of alpha olefinic sulphonate (AOS) and alkyl polyglucosides (APG). The intercalation of the surfactant into the clay was confirmed by XRD and FTIR and the morphology was studied by SEM. The process of granule formulation and the drying was carried out using rapid mix granulator and the fluidized-bed dryer, respectively, at the desired conditions of temperature an...

This article presents results of an experimental study on the flow characteristics of a pilot-size screw conveyor dryer (SCD). In particular, the effects of granular solids flow rate (15.2–206 kg/h) and screw speed (10.8–28 rpm) on the residence time distribution (RTD) were studied using sand as the model material. The RTD was measured using a dynamic step change in the solids flow rate. Parameters such as solids holdup, degree of fullness, mean residence time, and uniformity of the discharge flow were studied. The solids holdup and hence the degree of fullness was found to decrease with increase in the screw speed and decrease with the solids flow rate. The mean residence time was found to decrease with an increase in the screw speed, as expected. The screw speed and the solids flow rate strongly affected the discharge uniformity. An optimum value of the degree of fullness was observed with regard to the solids flow rate. Over the operating range examined, the solids flow pattern was close to plug flow, ...

The effects of various process variables and equipment components (geometry) on the performance of a screw conveyor dryer (SCD) were studied in terms of the material throughput and its uniformity, dryer load, specific consumption of mechanical energy, and heat transfer rate. The experimental results for drying of fine crystalline solids (50–100 µm particle size and 550 kg/m3 bulk density) in a 3-meter-long uninsulated jacketed screw conveyer dryer with a 0.072-m screw diameter have been used. The hydrodynamic performance of the SCD was also studied using sand particles of 350 µm size and 1500 kg/m3 bulk density (tapped). The maximum specific consumption of mechanical energy for conveying was found to be 1 kJ/kg. Moreover, the flow behavior of the material at the dryer discharge was found to depend strongly on the screw speed and the material feed rate.

The screw conveyor dryer (SCD) finds varied applications in the process industries either as a pre-dryer or for post-drying operation. In certain cases, it can be used as the main dryer. The full potential of SCD has not been exploited for the lack of its understanding. The conveying of paste or particles through a screw conveyor may follow a near plug flow behavior; however, it is essential to ascertain a desired level of inter-particle mixing during the course of drying/conveying so as to obtain the desired drying conditions. The effects of feed rate (15–176 kg/h) and screw speed (10.8–28 rpm) on the RTD were studied for the conveying of sand in a pilot-scale SCD using pulse input of a tracer (dye-coated sand). Two new parameters defining the relative stagnancy and screw effectiveness were introduced to study the flow performance of SCD. The flow in the SCD approaches plug flow with an increase in feed rate or by decrease in the screw speed. A low value of the holdback, a parameter of relative stagnancy...