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1.
This study was conducted to determine the optimal processing conditions for manufacturing instant sugar. The instant sugar was produced with a batch fluid bed agglomerator under the following conditions: inlet air temperature 60–90°C; water flow rate 1–3 mL min?1; and spraying time 1–10 min. The optimal conditions were estimated using response surface methodology as follows: inlet air temperature of 74.4°C, water flow rate of 2.85 mL min?1, and spraying time of 10 min. Subsequently, particle density of 1,550 kg m?3, poured density of 470.13 kg m?3, tapped density of 599.8 kg m?3, porosity of 62.1%, mean diameter of 324.66 µm, flowing time of 6.39 s, yield percentage of 78.96%, and desirability of 0.46 were obtained as optimal amounts. The results showed that the quadratic effects of water flow rate and spraying time on flowing time and particle density as well as the effects of spraying time and inlet air temperature on mean diameter and flowing time were significant. Within the temperature range of 60–90°C, the impact of spraying time and water flow rate on instant sugar properties had preference over inlet air temperature. Moreover, the optimal instant sugar required less dissolution time compare to various industrial sugar samples.  相似文献   

2.
In this study, production of pomegranate juice powder using a spray dryer was investigated. To prevent stickiness, maltodextrin dextrose equivalent 6 (DE6) was used as a drying agent. While feed flow rate, feed temperature, and air flow rate were kept constant, air inlet temperature (110–140°C), percentage maltodextrin (MD; maltodextrin dry solids/100 g feed mixture dry solids; 39.08–64.12%), and feed mixture concentration (19.61–44.11 °Brix) were chosen as the independent variables. Product properties investigated included moisture content, hygroscopicity, anthocyanin content, color change, solubility, bulk density, total phenolics content, antioxidant capacity, and sensory properties. The products were produced with high yield (86%) and high antioxidant activity (77%). MD and drying temperature were found to be the most important variables in production of pomegranate juice powders. Because total color change (ΔE), bulk density, antioxidant capacity, and powder yield were affected strongly by the independent variables, these parameters were used in optimization of the process. The optimum temperature, feed mixture concentration, and percentage maltodextrin were 100°C, 30.8 °Brix, and 53.5% MD, respectively. This study revealed that by applying these optimal conditions, pomegranate juice powder with a 55% dry solids yield, 9.78 total color change, 0.35 g/mL bulk density, and 57.8% antioxidant capacity were produced.  相似文献   

3.
Inrecent years, the use of spray drying for the production of anhydrobiotics has gained the interest of functional food manufacturers, mainly due to cost efficiencies and enhanced product and process flexibility (e.g., enhanced shelf life). In the present work, spray-drying conditions (air inlet temperature and feed flow rate) were optimized for the microencapsulation of the thermo sensitive probiotic lactobacilli strains Lactobacillus acidophilus stabilized in a 60:20:20 (w/w) maltodextrin: whey protein concentrate: D-glucose carrier. A 23 full-factorial experimental design was constructed with air inlet temperature (120, 140, and 160°C) and feed flow rate (6, 7.5, and 9.0 mL/min) as the independent variables and total viable counts (TVC), water activity (a w ), and cyclone recovery (CR) defined as the dependent variables. The increase in air inlet temperature from 120 to 160°C induced a significant (p < 0.001) reduction in the TVC from 9.02 to 7.20 log cfu/g, which corresponds to a97.5% loss of the L. acidophilus viable counts. On the other hand, the increase in the feed flow rate from 6 to 7.5 mL/min significantly reduced (p < 0.001) the heat-induced viability loss. A further increase in the feeding rate did not further modify the achieved thermo protection, and a detrimental impact of cyclone recovery (reduction) and water activity (increase) of the powder was observed. Using pruned quadratic mathematical models, the optimum spray-drying conditions for the production of maximally viable microencapsulated L. acidophilus were 133.34°C and 7.14 mL/min. The physicochemical and structural characteristics of the powders produced were acceptable for application with regards to residual water content, particles mean size, and thermo physical properties to ensure appropriate storage stability under room temperature conditions, with a low inactivation rate of L. acidophilus. Microcapsules appeared partially collapsed by scanning electron microscope with a spherical shape with surface concavities.  相似文献   

4.
Abstract

Revolving air flow was generated by oblique holes on air distribution board in a fluidized bed dryer. Such a revolving air flow shows a large scale velocity fluctuation in radial as well as tangential directions. This turbulent flow of air can fluidize the inert particles with superior performance than vibrated fluidized bed. The revolving fluidized bed is simpler in fabrication and easier in operation. For two types of inert particles tested, 4 mm glass beads and 4 mm × 5 mm Teflon cylindrical extrudates, the volumetric heat transfer coefficients were found to increase with the liquid feed flowrate and air flow velocity but decrease with the air inlet temperature, height of static bed, and liquid concentration. The revolving fluidized bed gives an increase of volumetric heat transfer coefficient by 1 kW/m3 K, and represents a 15–25% enhancement from ordinary fluidized bed operated at a bed height of 60 mm, bed diameter of 140 mm, superficial air flow velocity of 3.5 m/s, liquid feed (Soya milk) flowrate of 20 mL/min at a concentration of 6.7%, and a temperature ranges of 80–140°C using Teflon extrudates as inert particles.  相似文献   

5.
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 (aw), flowability, porosity, and percentage retention of gingerol.  相似文献   

6.
ABSTRACT

Phenolic compounds have been reported to show both antioxidant and pro-oxidant properties. The effects of spray drying conditions on the balance between antioxidant and pro-oxidant properties of orange peel extract have been evaluated in this work. The inlet drying temperatures (ranging between 100 and 175°C) gave no significant effect on the redox recoveries. On the other hand, the main air flow rate (between 28 and 38?m3/h) and feed pump rate (between 4 and 7?mL/min) significantly affected the pro-/antioxidant recovery ratio. The ratios of pro-/antioxidant recovery were found to be between 1.00 and 1.13, and the pro-oxidant and antioxidant recoveries in this study were found to be between 87–96 and 83–93%, respectively.  相似文献   

7.
《Drying Technology》2013,31(4-5):1035-1051
ABSTRACT

Drying of okara, an insoluble pulp residue waste byproduct of tofu production, was investigated in a continuously moving bed of inert particles subjected to vortex-like motion. The experimental variables in their respective ranges included the mass of Teflon pellets used as inert particles (0.4–1.2 kg), feed rate (0.5–1.4 kg/h), inlet air temperature (100–145°C) and airflow rate (195–271 m3/h). The dryer showed good performance in general and produced dry okara with moisture content ranging from 5 to 33% wb depending upon the operating conditions. The product recovery ranged from 80 to 90% on dry basis in most experiments. The specific water evaporation rate in okara drying increased with increasing of the feed rate and mass of Teflon pellets. However, the specific heat consumption decreased with an increase in the okara feed rate. Results showed that specific heat consumption for okara drying in a bed of inert particles was about 3 to 4 times higher in comparison with that of free water.  相似文献   

8.
This study evaluated the influence of wall material concentration (10–30%), inlet temperature (135–195°C), and feed rate (0.5–1.0 L · h?1) on the properties of rosemary oil microencapsulated by spray-drying, with gum arabic as carrier. Powder recovery, surface oil, oil retention, and hygroscopicity varied from 17.25%–33.96%, 0.03%–0.15%, 7.15%–47.57%, and 15.87%–18.90%, respectively. The optimized conditions were determined to be a wall material concentration of 19.3%, an inlet air temperature of 171°C, and a feed flow rate of 0.92 L · h?1. At this condition, particles presented no fissures and the compositions of pure and microencapsulated oil were similar. The sorption isotherms could be described by the GAB model.  相似文献   

9.
The objectives of this research were to investigate empirical and diffusion models for thin-layer crumb rubber drying for producing STR20 rubber using hot air temperatures of 110–130°C and to study the effect of drying parameters such as inlet drying temperature, volumetric flow rate, and initial moisture content on the quality of dried rubber. Finally, a mathematical drying model for predicting the drying kinetics of crumb rubber was developed using inlet air flow rates of 300–600 m3/min-m3 of crumb rubber (equivalent to 1.8–5.0 m/s) with the crumb rubber thickness fixed at 0.25 m. The average initial moisture content of samples was in the ranges of 40 and 50% dry basis while the desired final moisture content was below 5% dry basis. The results showed that the drying equation of crumb rubber was highly related to the inlet air temperature, while the drying constant value was not proportional to the initial moisture content. Consequently, the experimental data were formulated using nine empirical models and the analytical solution of moisture ratio equation was developed by Fick's law of diffusion. The result showed that the simulated data best fitted the logarithmic model and was in reasonable agreement to the experimental data. The effective diffusion coefficient of crumb rubber was in the range of 1.0 × 10?9 to 2.15 × 10?5 m2/s corresponding to drying temperatures between 40 and 150°C, respectively. The effects of air recirculation, inlet drying temperature, initial moisture contents, air flow rate, and drying strategies on specific energy consumption and quality of samples were reported. The experiments were conducted using two different drying strategies as follows: one-stage and two-stage drying conditions. The results showed that initial moisture content and air flow rates significantly affected the specific energy consumption and quality of rubber, while the volumetric air flow rate acted as dominant effect to the specific energy consumption. The simulated results concluded that the percentage of recycled air between 90 and 95% provided the lowest specific energy consumption as compared to the others.  相似文献   

10.
ABSTRACT

Barley grass (Triticum aestivum L.) is popular, commonly known as a nutritional supplement in China. To obtain the highest chlorophyll and flavonoid content as well as other physicochemical characteristics, spray drying from barley grass juice was carried out for two different maltodextrin concentrations (10 and 20%, dried basis) and four different inlet air temperatures (140, 150, 160, and 170°C). After drying, color, water activity, odor, taste, density, particle size, glass transition temperature, and chlorophyll and flavonoid contents of the dried product were measured. Highest contents of flavonoid (5.66?mg/kg) and chlorophyll (7.29?mg/kg) were obtained under 150°C inlet air temperature, 10% maltodextrin concentration, at a feed flow rate of 1.8?L/h for the drying. Corresponding particle size was 19.58–13.33?µm. The glass transition temperature (Tg) increased with the increasing of maltodextrin concentration; and two max Tg of powder obtained from 10 and 20% maltodextrin concentration were 74.4 and 77.4°C, respectively. Retention of taste and flavor were highest with 20% maltodextrin. High inlet air temperature was contributed to the large discrepancy of odor and taste substances. The best color (lightness L*?=?64.44 and greenness b*?=??11.53) was obtained at 150°C inlet air temperature and 10% maltodextrin concentration. Both maltodextrin concentrations resulted in poor flowability of the dried product (CI?≤?32.51).  相似文献   

11.
Central composite design (CCD) was applied in this work to analyze the performance of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) flat sheet membrane in the seawater desalination using direct contact membrane distillation (DCMD) process. It is the most popular in response surface method (RSM). Development on Quadratic Regression model for membrane performance as a function of the operating conditions was studied. The ranges for each operating condition were selected as follows: feed temperature (Tf): 48–58?°C, feed flow rate (Qf): 80–180?mL/min, permeate temperature (Tp):17–22?°C and permeate flow rate (Qp): 80–180?mL/min. The model R-squared of 0.9759 (adjusted to degree-of-freedom), Lack-of-fit test (p?=?0.4764), predicted residual error sum of squared (PRESS) statistic of 10.3 suggest that the model is adequate to correlate the impact of operating conditions on permeates. ANOVA analysis showed that factors as feed flow rate, feed temperature, and permeate temperature have a valuable impact (p?≤?0.05) on the response variable. Additionally, the interaction among feed temperature-feed flow rate, feed flow rate-permeate flow rate, and the quadratic impact of feed temperature, permeate temperature, and permeate flow rate have shown an important impact (p?≤?0.05) on the permeate flux. Optimization of operating conditions to make the permeate flux and salt rejection high as possible was determined according to desirability function approach. A desirability of 0.969 was achieved at a feed temperature of 58?°C, feed flow rate of 180?mL/min, permeate temperature of 18.8?°C, and permeate flow rate of 145.3?mL/min in which a permeate flux of 12.56?kg/m2h and a salt rejection of 99.97% was obtained.  相似文献   

12.
A novel trickling fibrous-bed bioreactor was developed for biofiltration to remove pollutants present in contaminated air. Air containing benzene as the sole carbon source was effectively treated with a coculture of Pseudomonas putida and Pseudomonas fluorescens immobilized in the trickling biofilter, which was wetted with a liquid medium containing only inorganic mineral salts. When the inlet benzene concentration (Cgi) was 0·37 g m−3, the benzene removal efficiency in the biofilter was greater than 90% at an empty bed retention time (EBRT) of 8 min or a superficial air flow rate of 1·8 m3 m−2 h−1. In general, the removal efficiency decreased but the elimination capacity of the biofilter increased with increasing the inlet benzene concentration and the air (feed) flow rate. It was also found that the removal efficiency decreased but the elimination capacity increased with an increase in the loading capacity, which is equal to the inlet concentration divided by EBRT. The maximum elimination capacity achieved in this study was ∽11·5 g m−3 h−1 when the inlet benzene concentration was 1·7 g m−3 and the superficial air flow rate was 3·62 m3 m−2 h−1. A simple mathematical model based on the first-order reaction kinetics was developed to simulate the biofiltration performance. The apparent first order parameter Kl in this model was found to be linearly related to the inlet benzene concentration (Kl=4·64−1·38 Cgi). The model can be used to predict the benzene removal efficiency and elimination capacity of the biofilter for benzene loading capacity up to ∽30 g m−3 h−1. Using this model, the maximum elimination capacity for the biofilter was estimated to be 12·3 g m−3 h−1, and the critical loading capacity was found to be 14 g m−3 h−1. The biofilter had a fast response to process condition changes and was stable for long-term operation; no degeneration or clogging of the biofilter was encountered during the 3-month period studied. The biofilter also had a relatively low pressure drop of 750 Pa m−1 at a high superficial air flow rate of 7·21 m3 m−2 h−1, indicating a good potential for further scale up for industrial applications. © 1998 Society of Chemical Industry  相似文献   

13.
In the present study, attempts are made to optimize digestion time, initial feed pH, feed temperature, and feed flow rate (organic loading rate, OLR) for maximum yield of methane gas and maximum removal of chemical oxygen demand (COD) and biological oxygen demand (BOD) of sugar industry wastewaters in three‐phase fluidized‐bed bioreactor. Methane gas is analysed by using flame‐ionisation detector (FID). The optimum digestion time is 8 h and optimum initial pH of feed is observed as 7.5. The optimum temperature of feed is 40°C and optimum feed flow rate is 14 L/min with OLR 39.513 kg COD/m3 h. OLR is calculated on the basis of COD inlet in the bioreactor at different flow rates. The maximum methane gas concentration is 61.56% (v/v) of the total biogas generation at optimum biomethanation process parameters. The maximum biogas yield rate is 0.835 m3/kg COD/m3 h with maximum methane gas yield rate (61.56%, v/v) of 0.503 m3/kg COD/m3 h at optimum parameters. The maximum COD and BOD reduction of the sugar industry wastewaters are 76.82% (w/w) and 81.65% (w/w) at optimum biomethanation parameters, respectively.  相似文献   

14.
Maize (Zea mays) is a cereal grown in Brazil, and its availability is limited to the harvest season. An alternative processing route is based on the production of green corn powder, which has a longer shelf-life and increased versatility. This study aimed to evaluate the influence of drying conditions on the physical characteristics, size, and morphology of green corn powder. Drying experiments were performed on a spray dryer according to a central composite rotational design to evaluate inlet air temperature, feed flow rate, and pulp concentration. The yield of dried pulp corn had an average value of 36.19%. The following mean values for the physical properties of the powder were measured: solubility of 94.37 g/100 g, wettability of 128.05 seconds, moisture content of 1.97%, water activity of 0.13, density of 0.79 g/mL, and a particle diameter of 31.02 µm. The powder was also yellow with less intensity, and the particle surface was smooth at higher temperatures and had a tendency to form agglomerates. The estimated optimal conditions for spray drying were 48% (w/w) pulp concentration, 172°C inlet air temperature, and feed flow rate of 0.56 L/h.  相似文献   

15.
Abstract

Enzyme-assisted aqueous extraction processing (EAEP) is an environmentally friendly technology that simultaneously extracts both oil and protein. It has shown to be commercial feasibility for high oil recovery (~97%) and favorable protein functionality properties. The present study used soy skim, the liquid co-products obtained using EAEP to produce a polypeptide-rich spray-dried powder. The effects of inlet drying air temperature (140?°C, 160?°C, 180?°C and 200?°C), feed flow rate (3, 6, 9, and 12?mL/min), and solids concentration (25%, 30%, 35%, and 40%) on the properties of the polypeptide-rich powders were investigated. Water activity (aw), color characteristics, bulk density, Carl Index (CI), Water Solubility Index (WSI), micro-morphology, peptide distribution, and antioxidant capacity were significantly affected by different spray-drying parameters. The results of antioxidant capacity test showed that the spray drying conditions significantly affected the antioxidant capacity of the polypeptide-rich powders. The polypeptide molecular weight size and distribution, the composition of the peptide chain, and the cross-linking with other substances could all affect its antioxidant capacity. Overall, good quality polypeptide-rich powders in terms of physicochemical characteristics, micro-morphology, and functional properties can be produced by spray-drying at an inlet temperature of 160?°C, a feed flow rate of 6?mL/min, and solids concentration of 35%.  相似文献   

16.
Industrial production of lactose hydrolyzed milk powder (LHMP) remains challenging. Due to the presence of the monosaccharides glucose and galactose, lactose-free powders tend to suffer stickiness, caking, and browning during drying and storage. We sought to find ideal conditions spray dryer inlet air temperature (θair,in) and concentrated milk flow rate (mCM) for LHMP production. We tested θair,in settings of 115–160°C and mCM of 0.3–1.5?kg?·?h?1, and also applied mass and energetic balances. LHMP generally exhibited higher mass and energetic losses than the control (milk powder containing lactose), as a consequence of the relatively low dryability of LHMP. For a lab scale spray dryer, the ideal conditions settings for LHMP production were θair,in?=?145?±?2°C and mCM?=?1.0?kg?·?h?1, taking into account the mass yield and energetic cost (kJ?·?kg?1 of powder) of the process. These ideal conditions are a potential tool for the industrial development of lactose-free dairy powders.  相似文献   

17.
Benqin Yang 《Drying Technology》2013,31(10):1188-1198
A proven bioevaporation process was used to treat food waste (FW) by mixing ground FW with biodried sludge (BS). Organic loading (OL), moisture content (MC), and air flow rate (Qg) showed significant influences on FW bioevaporation performance. Single-parameter experiments for MC and Qg were conducted and ranges were determined to be 55–67 wt% and 0.04–0.14 m3/kg TSmixture · h, respectively. In order to optimize the FW bioevaporation process, a central composite design (CCD) and response surface method (RSM) were applied over the preselected ranges of OL (0.00–0.16 kg VSFW/kg TSBS), MC (50.91–71.09 wt%), and Qg (0.01–0.17 m3/kg TSmixture · h). The results indicated that OL of 0.06 kg VSFW/kg TSBS, MC of 59.2 wt%, and Qg of 0.09 m3/kg TSmixture · h were the optimal conditions for the FW bioevaporation process. Water evaporation of 123.1% and VS degradation of 108.4% were obtained under these estimated optimal conditions.  相似文献   

18.
The influence of pulsed electric field (PEF) and subsequent centrifugal osmotic dehydration (OD) on the convective drying behavior of carrot is investigated. The PEF was carried out at an intensity of E = 0.60 kV/cm and a treatment duration of t PEF  = 50 ms. The following centrifugal OD was performed in a sucrose solution of 65% (w/w) at 40°C for 0, 1, 2, or 4 h under 2400 × g. The drying was performed after the centrifugal OD for temperatures 40–60°C and at constant air rate (6 m3/h).

With the increase of OD duration the air drying time is reduced spectacularly. The dimensionless moisture ratio Xr = 0.1 is reached for PEF-untreated carrots after 370 min of air drying at 60°C in absence of centrifugal OD against 90 min of air drying after the 240 min of centrifugal OD. The PEF treatment reduces additionally the air drying time. The total time of dehydration operations can be shortened when OD time is optimized. For instance, the minimal time required to dehydrate untreated carrots until Xr = 0.1 is 260 min (120 min of OD at 40°C and 140 min of drying at 60°C). It is reduced to 230 min with PEF-treated carrots.

The moisture effective diffusivity D eff is calculated for the convective air drying based on Fick's law. The centrifugal OD pretreatment increases drastically the value of D eff . For instance, 4 h of centrifugal OD permitted increasing the value of D eff from 0.93 · 10?9 to 3.85 · 10?9 m2/s for untreated carrots and from 1.17 · 10?9 to 5.10 · 10?9 m2/s for PEF-treated carrots.  相似文献   

19.
During the industrial processing of pomegranate, large volumes of industrial wastes (seeds, peels, leaves) are produced, which have a wide range of nutritional values. In this work, a new method for pomegranate seed application in food industries was developed based on the extraction of seed oil and its subsequent encapsulation by spray drying. Skimmed milk powder was used as encapsulating agent. Ratio of core to wall material, feed solids concentration, inlet air temperature, and drying air flow rate were the factors investigated with respect to encapsulation efficiency using a central composite design. The resulting microcapsules were evaluated in terms of moisture content, particle size, bulk density, and hygroscopicity. The optimum operating conditions were found to be: ratio of core to wall material, 1/9; feed solids concentration, 30% (w/w); inlet air temperature, 187 °C; drying air flow rate, 22.80 m3/h. Under these conditions, the maximum encapsulation efficiency was about 95.6%.  相似文献   

20.
《分离科学与技术》2012,47(12):1768-1776
The fructan separation from a model sugar solution and natural agave juice was studied using a stirred-cell nanofiltration unit operated in concentration mode. Hydrophilic cellulose membrane with MWCO of 1000 Da was used. The experimental conditions were varied to predict the influence of pressure (0.14–0.350 MPa) and feed concentration (0.15–0.25 g/mL) on the initial permeate flux and solute retained fraction (SRF) values of the process. Response surface plots (p < 0.05) showed that the permeate flux and SRF increased significantly with the pressure and decreased with feed concentration. The permeate flux varied from 0.5 to 4.1 L · h?1 · m?2. The fructan retained fraction in model sugar solution varied from 0.85 to 0.97 whereas fructose, glucose and sucrose presented similar SRF values ranging from 0.38 to 0.65. Promising results were obtained when natural agave juice was used.  相似文献   

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