Effects of spray drying on Lactobacillus plantarum BM-1 viability,resistance to simulated gastrointestinal digestion,and storage stability

The aim of this study was to evaluate the applicability of spray drying in the production of high-viability powder of L. plantarum BM-1. Firstly, in order to improve the survival of L. plantarum BM-1 during spray drying, different protectants were added before drying. The results showed that the highest survival rate of 75.70% and the lowest moisture content of 3.67% were achieved with the combination of reconstituted skim milk (RSM) and equal weight sucrose as protective agent. The cell counts reduction of free L. plantarum BM-1 was 2.58 log CFU/ml after exposure to 60°C for 1 min, whereas the reduction in spray-dried cells protected by RSM and sucrose was only 0.08 log CFU/ml. After 120-min incubation in simulated gastric condition, cell counts of free L. plantarum BM-1 decreased approximately 1.4 log CFU/ml, whereas no significant (p > 0.05) reduction in spray-dried cells was observed. Compared to the free cells, the spray-dried cells also showed higher survival under bile salts stress. In addition, the bacteriocin production of L. plantarum BM-1 was not affected during spray drying. Furthermore, the survival rate of spray-dried powder reached 98% after storage for 2 months at 4°C, and a nitrogen replacement package was shown to be better than a vacuum package and air-sealed package at room temperature. Therefore, the combination of equal weight RSM and sucrose is a promising protective agent for L. plantarum BM-1 during spray drying.     

Optimization of Spray Drying of Ginger Extract

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 spray drying were decided on the basis of different responses such as moisture content, water activity (a_w), flowability, porosity, and percentage retention of gingerol.     

Viability of Lactobacillus plantarum TISTR 2075 in Different Protectants during Spray Drying and Storage

Spray drying was applied for the production of Lactobacillus plantarum TISTR 2075 powder using maltodextrin as the carrier. A survival rate of 0.85% was achieved for this probiotic bacteria after spray drying. To improve the survival of this strain during the spray-drying process and storage, various protectants were added before drying. These included protein, trehalose, fibersol, ascorbic acid, isomalt, palatinose, and gum acacia. The results indicated that trehalose and protein (a combination of soy protein isolate and milk protein concentrate) significantly (P < 0.05) enhanced the viability during spray drying, with survival rates of 57.70 and 25.31%, respectively. Survival of the dried strain was also monitored over a period of 12 months’ storage at 4 and 25°C. Higher temperature induced lower viability of the strain in all protectants during this long-term storage. Accelerated storage tests using temperatures of 37, 45, 60, and 80°C were also applied to the spray-dried powders. A temperature-dependent prediction model was developed to determine the viability of the spray-dried L. plantarum TISTR 2075 in different protectants for long-term storage.     

Optimization of Process Parameters for Spray Drying of Fermented Soy Milk

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 obtained at high air flow rate and low feed flow rate. The increase in the atomization pressure increases the cohesiveness between particles, resulting in reduced flowability. An increase in the inlet air temperature greatly reduces the viability and the isoflavone aglycone content in the product. Protein denaturation during the process was found to reduce the product solubility.     

Thin-Layer Drying Characteristics and Quality Evaluation of Air-Dried Ganoderma Tsugae Murrill

Ganoderma is normally dried to extend its shelf life without using chemical preservative and to concentrate the medicinal value in the fruiting body. Convective hot air drying characteristics of Ganoderma tsugae Murrill were evaluated in hot air circulated oven at different drying temperatures, sizes, and air flow rates. The drying kinetics of Ganoderma tsugae in kidney shape and slices were investigated and compared at different drying conditions. The variation of effective moisture diffusivity values at decreasing moisture contents during drying was determined from the drying data. Four well-known thin-layer drying models were fitted to the experimental data and the Midilli model was found to satisfactory describe the drying characteristics of kidney-shaped Ganoderma tsugae. Ganoderma tsugae dried at 50°C with air velocity of 1.401 ms^?1 showed the highest retention of crude ganoderic acid content compared to other drying conditions.     

Optimization of Spray Drying of an Innovative Functional Food: Fermented Mixed Juice of Carrot and Watermelon

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 content of the dried powder. Increased atomization pressure increased the cohesiveness but decreased flowability of the dried powder because the particle size was lowered. The probiotic powder was further analyzed using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC).     

Drying Kinetics and Physicochemical Characteristics of Laboratory-Prepared Corn/Wheat Distillers Grains and Solubles Dried with Superheated Steam and Hot Air

The effect of superheated steam (SS) drying and hot air (HA) drying on drying kinetics and changes in the color, crude protein, and amino acid concentrations (in particular, lysine content) of corn/wheat wet distillers grains (WDG) and centrifuged solubles (CS) was evaluated. An inversion temperature was reached at 139°C for WDG and 132°C for CS, above which moisture evaporation rate and qualitative changes under SS drying conditions exceeded the values noted in HA, and below which the reverse was observed. A significant decrease (from 8 to 50%) in the lysine content of WDG and CS was reported during SS and HA. The overall changes in the color (ΔE*) of corn/wheat WDG and CS ranged from 7.9 ± 2.6 to 27.2 ± 1.9 during SS drying and from 11.9 ± 3.7 to 32.0 ± 0.5 during HA drying. The observed deterioration in color was attributed mainly to changes in lightness (L*) and yellowness (b*) of dried samples. The values of L* and b* were reliable predictors of the lysine content of corn/wheat distillers co-products.     

Effect of Fluidized Bed Drying Temperature on Various Quality Attributes of Paddy

Abstract

As reported by many researchers, it was found that fluidized bed paddy drying using high drying air temperatures of over 100°C affected the head rice yield and whiteness of dried rice. However, only a few studies on fluidized bed paddy drying with drying air temperatures below 100°C were so far reported. The main objective of this work was therefore to study the effect of fluidized bed drying air temperature on various quality parameters of Suphanburi 1 and Pathumthani 1 Indica rice. Paddy was dried from the initial moisture contents of 25.0, 28.8, and 32.5% dry basis to 22.5 ± 1.2% dry basis using inlet drying air temperatures between 40 and 150°C at 10°C/step. After fluidized bed drying, paddy was tempered and followed by ambient air aeration until its final moisture content was reduced to 16.3 ± 0.5% dry basis. The results showed that the head rice yield of Suphanburi 1 was significantly related to the inlet drying temperature and initial moisture content whilst there was no significant relationship between the head rice yield, drying temperature and initial moisture content for Pathumthani 1. The whiteness of the two rice varieties was slightly decreased with increase in drying air temperature and initial moisture content. It was also found that the hardness of both cooked rice varieties exhibited insignificant difference (p < 0.05) comparing to rewetted rice, which was gently dried by ambient air aeration in thin layer. The thermal analysis by DSC also showed that partial gelatinization occurred during drying at higher temperatures. Using inlet drying air temperatures in the range of 40–150°C therefore did not affected the quality of cooked rice and paddy. The milling quality of paddy was also well maintained.     

Non-destructive Measurement of Moisture Distribution in Wood during Drying Using Digital X-ray Microscopy

The objective of this study was to develop a nondestructive method by which moisture distribution in wood during drying could be predicted. A newly developed digital X-ray microscope was used to measure the moisture content of wood and its accuracy and resolution was evaluated compared to the classic oven-dry method.

Small green wood specimens of Sugi (Cryptomeria japonica D. Don) were cut and dried under constant temperature and humidity. As the weight was decreasing during drying, X-ray microscope images of cross section were obtained. From these digital images and specimen weight, the moisture content during drying was measured by the two methods. After the shrinkage of the specimen was canceled, the standard error achieved finally was about 1% moisture content within the experimental range. As the image was divided into small subimages, the clear moisture distribution can be seen. It was found that the image divided into 32 × 32 subimages in each size of 0.625 × 0.625 mm might be valid to determine the moisture distribution, and that the drying rate in early wood is larger than in late wood.     

Drying Kinetics of Instant Asian Noodles Processed in Superheated Steam

The objective for this work was to develop a novel technique for creating instant noodles by determining the drying kinetics of noodles undergoing simultaneous drying and processing using superheated steam. The mathematical model of moisture ratio was differentiated to determine the drying rates of noodles during processing. There was a constant rate drying period for all temperatures at a steam velocity of 1.5 m/s but there was no constant rate drying period at a steam velocity of 0.5 m/s. The constant rate drying period suggested by measurement of internal noodle temperature is much longer and well defined for all processing conditions than from the drying curves. The constant drying rate period, was nearly 200 s at 110°C but decreased to 50 s at 150°C. Equilibrium moisture content isobars were determined from mass changes during superheated steam processing. It was determined that isotherm equations for equilibrium moisture content in hot air systems may be utilized to model isobars in superheated steam systems.     

Drying and Testing of Mint (Mentha piperita) by a Hybrid Photovoltaic-Thermal (PVT)-Based Greenhouse Dryer

Mint has been used as a medicinal and aromatic plant since ancient times. Its leaves are used for flavoring, spicing, and mint oil, which is used to treat several diseases. In order to preserve this seasonal plant for consumers during the year, it undergoes various technological treatments, such as drying. The economy of medicinal plant production is burdened considerably by the energy costs of drying. To substitute high-cost fossil energy, a hybrid photovoltaic-thermal (PVT) ultraviolet (UV)-stabilized polyethylene greenhouse dryer was developed to lower the initial costs. The drying process from an initial moisture content of 80% wb to a final moisture content of 11% wb takes 21 h. Testing was done for different samples of dried mint powder and comparison was made to fresh samples. The results show that nutritional and calorific values are retained along with a major degree of its original color, which, coupled with a significant reduction in moisture content, resulted in longer shelf life of the dried product. Further, the results show that the efficiency of the dryer and net CO₂ mitigation over the lifetime was 34.2% and 140.97 tons, respectively. The carbon credit earned ranges from a minimum of $704.85 per ton of C to a maximum of $2,819.40 per ton of C.     

Scope of vacuum press drying for fast removal of moisture below fiber saturation point

Studies were taken up on 25 mm thick samples of Tectona grandis to understand its drying behavior under vacuum press drying. Five different vacuum level–temperature combinations were used in the study to observe the moisture reductions achieved. The results were analyzed to understand which combination gave maximum moisture content reduction from two moisture content ranges: one above and the other below the fiber saturation point of the species. It was found that the samples could be dried to less than 13% moisture content levels from about 25% moisture content levels effectively in just two runs approximately lasting 7 h each. More interestingly, the moisture removal by this method was found more effective when samples were seasoned from initial moisture content levels below the fiber saturation point. This study will pave way for developing schedules for T. grandis for faster and degrade-free seasoning.     

Kiln drying behavior utilizing drying rate of lumber from six fast-growth plantation species in Costa Rica

The objective was to study the effect of the drying time and moisture content variations on the drying rate during kiln drying. The moisture content is a good predictor of the variation in drying rate; to determine the drying rate, the model DR =a * t + b (where DR is the drying rate, t is the drying time, and a and b are constants) was used. Cordia alliodora, Dipterix panamensis, Hieronyma alchorneoides, and Vochysia ferruginea show a unique tendency, whereas Enterololium cyclocarpum and Samanea saman showed two tendencies. Drying rate in relation to time showed that it is possible to define the various stages during drying and the inflexion points in time where a change in the drying rate occurs. Two types of tendencies are shown in the drying rate vs. time relation in C. alliodora, E. cyclocarpum, and S. saman, whereas three tendencies appear in D. panamensis, H. alchorneoides, V. ferruginea. C. alliodora, E. cyclocarpum, and S. saman presented only one inflexion in the drying rate, which can be maintained at an average of 24.5, 11.64, and 7.83%/day, respectively, for those species. On the other hand, D. panamensis, H. alchorneoides, and V. ferruginea showed two inflexions.     

Evaluating a Solar Dryer for In-Shell Drying of Split Pistachio Nuts

Abstract

A thin-layer forced air solar dryer was designed to study the feasibility of drying pistachio nuts. The dryer was tested during the 2001 and 2002 drying seasons. The maximum temperature in the solar collector reached 56°C, which was 20°C above the ambient temperature. The required drying time was 36 h. During the first day of drying (0800 to 1700 h) the moisture content dropped to about 21% (wb). The final moisture content of the dried nuts was 6% wb, which was 1% below the recommended storage moisture. The drying constant of the pistachio nuts during solar drying was determined using two mathematical models, a one-term series solution of Fick's diffusion equation and an exponential decaying model. There was no significant difference between the two models (α = 0.05). In general, the quality of solar dried nuts was better than the conventional heated air due to slower drying rates.     

Determination of Drying Characteristics of Timber by Using Artificial Neural Networks and Mathematical Models

In this research, poplar and pine timbers have been dried in heat pump dryer functioning on the basis of 24-h operation. The change in weight in all of the timbers was followed in the drying chamber and drying stopped when the desired weight was achieved. Initial moisture content of the poplar timbers was 1.28 kg water/kg dry matter, and the moisture content was reduced to 0.15 kg water/kg dry matter moisture content in 70 h; the moisture content of the pine timbers, which was 0.60 kg water/kg dry matter, was reduced to the same amount in 50 h. Drying air temperature, relative humidity, and stack weight were measured and collected during drying and saved on a computer and analyzed afterwards. The moisture ratios were analyzed with Statgraphic computer program by using semitheoretical models and empirical values. Correlation and standard error of estimation (SEE) and R ² values were achieved.     

Experimental and Simulated Performances of a Batch-Type Longan Dryer with Air Flow Reversal Using Biomass Burner as a Heat Source

This article presents experimental performance of a batch-type longan dryer using a biomass burner with air flow reversal and also presents modeling of the longan dryer for drying of whole longan. The dryer essentially consists of a biomass burner and a drying bin with an arrangement for periodic air flow reversal. Three drying runs with loading capacity of 2,000, 1,500, and 1,000 kg of whole longan were carried out. There was no significant difference in temperatures in different positions (except inlet and outlet) inside the dryer (p < 0.05) or moisture content inside the dryer (p < 0.05). Whole longan was dried from an initial moisture content of 74% (wb) to a final moisture content of 14% (wb). The drying time of whole longan in the longan dryer was 60, 54, and 48 h for 2,000, 1,500, and 1,000 kg loading, respectively. The quality of dried product was also good in comparison to the high-quality product in markets.

To simulate the performance of the longan dryer for drying of whole longan, a set of partial differential equations was developed and the equations were solved using the finite difference technique. The numerical solution was programmed in Compaq Visual FORTRAN version 6.5 (Compaq Computer Corp., TX). The simulated moisture contents agreed well with the experimental data. This model can be used to provide the design data and it is also essential for optimal dryer design.     

Microwave Drying Kinetics of Okra

In this work, the effects of power level and sample mass on moisture content, moisture ratio, drying rate, and drying time of Turkey okra (Hibiscus esculenta L.) were investigated using microwave drying technique. Various microwave power levels ranging from to 180 to 900 W were used for drying of 100 g of okra. To investigate the effect of sample mass on drying, the samples in the range of 25 to 100 g were dried at microwave power level of 360 W. To determine the kinetic parameters, the drying data were fitted to various models based on the ratios of the differences between the initial and final moisture contents and equilibrium moisture content. Among of the models proposed, Page's model gave a better fit for all drying conditions used. The activation energy for microwave drying of okra was calculated using an exponential expression based on Arrhenius equation and was found to be 5.54 W/g.     

An Effective Moisture Diffusivity Model Deduced from Experiment and Numerical Solution of Mass Transfer Equations for a Shrinkable Drying Slab of Microalgae Spirulina

From experimental data, Spirulina effective moisture diffusivity was analytically estimated by considering two diffusion regions and the product shrinkage. Then, the moisture diffusivity was deduced from the numerical solutions of mass transfer equations by minimizing the difference between experimental and simulated drying curves and by taking into account the slab thickness variation. The range of moisture diffusivity used for simulations was estimated from minimal and maximal values of experimental effective diffusivities and calculation started with the mean value of experimental effective diffusivities. Identified effective diffusivities ranged from 1.79 × 10^?10 to 6.73 × 10^?10 m²/s. These diffusivities increased strongly with drying temperature and decreased slightly with moisture content. A suitable model correlating effective diffusivity, temperature, and moisture content was then established. Effective diffusivities given by this model were very close to experimental ones with a relative difference ranging from 0.5 to 24%.     

Attrition of Victorian brown coal during drying in a fluidized bed

Analyzing the attrition of Victorian brown coal during air and steam fluidized bed drying, the change in particle size distribution over a range of initial moisture contents (60% to 0%) and residence times (0 to 60 minutes) was determined. Dried at a temperature of 130°C with a fluidization velocity 0.55 m/s and an initial particle size of 0.5–1.2 mm, both fluidization mediums show a shift in the particle size distribution between three and four minutes of fluidization, with a decrease in mean particle size from 665 µm to around 560 µm. Using differential scanning calorimetry (DSC), the change in particle size has been attributed to the transition between bulk and non-freezable water (approximately 55% moisture loss) and can be linked to the removal of adhesion water, but not to fluidization effects. This is proved through the comparison of air fluidized bed drying, steam fluidized bed drying, and fixed bed drying—the fixed bed drying is being used to determine the particle size distribution as a function of drying. The results show the three drying methods produce similar particle size distributions, indicating that both fluidization and fluidization medium have no impact upon the particle size distribution at short residence times around ten minutes. The cumulative particle size distribution for air and steam fluidized bed dried coal has been modeled using the equation P_d = A₂ + (A₁ ? A₂)/(1 + (d/x₀)^p), with the resultant equations predicting the effects of moisture content on the particle size distribution. Analyzing the effect of longer residence times of 30 and 60 minutes, the particle size distribution for steam fluidized bed dried coal remains the same, while air fluidized bed dried coal has a greater proportion of smaller particles.     

Online measurement of moisture content,moisture distribution,and state of water in corn kernels during microwave vacuum drying using novel smart NMR/MRI detection system

Moisture content is unevenly distributed and hard to measure when agricultural products are dried using microwave drying. A low-field nuclear magnetic resonance/imaging (NMR/MRI) and microwave vacuum drying (MVD) combination equipment was developed. The residual moisture content, distribution, and state of water (free, immobilized, and bound) in fresh corn kernels during MVD were quickly measured in real time. NMR results indicated that the amplitude of free and immobilized water decreased very rapidly at the early stage of MVD, while the amplitude of bound water experienced a similar rapid decrease at the last stage. MRI results indicated that the moisture content was always distributed unevenly during MVD, especially at the early stage. The moisture distribution tended to become uniform when drying progressed and the bound water became dominant. The residual moisture content of corn kernels and integral (total) amplitude of NMR were found to fit well with a linear model (R²?>?0.991, P?相似文献