Artificial neural network techniques to predict the moisture ratio content during hot air drying and vacuum drying of Radix isatidis extract

Background:To predict the moisture ratio of Radix isatidis extract during drying.Methods:Artificial neural networks were designed using the MATLAB neural network toolbox to produce a moisture ratio prediction model of Radix isatidis extract during hot air drying and vacuum drying,where regression values and mean squared error were used as evaluation indexes to optimize the number of hidden layer nodes and determine the topological structure of artificial neural networks model.In addition,the drying curves for the different drying parameters were analyzed.Results:The optimal topological structure of the moisture ratio prediction model for hot air drying and vacuum drying of Radix isatidis extract were“4-9-1”and“5-9-1”respectively,and the regression values between the predicted value and the experimental value is close to 1.This indicates that it has a high prediction accuracy.The moisture ratio gradually decreases with an increase in the drying time,reducing the loading,initial moisture content,increasing the temperature,and pressure can shorten the drying time and improve the drying efficiency.Conclusion:Artificial neural networks technology has the advantages of rapid and accurate prediction,and can provide a theoretical basis and technical support for online prediction during the drying process of the extract.

Effects of Chemical Osmotic Pretreatment on Drying Characteristics and Quality of Blueberry under Hot Air Drying

In order to study the effects of chemical osmotic pretreatment on the characteristics and quality of blueberry under hot air drying,fresh blueberries were pretreated with 2.5 g/100 mL K2CO3+0.6 g/100 mL olive oil,and 5.0 g/100 mL K2CO3+0.6 g/100 mL olive oil at(45±0.5)℃,respectively.The changes of water content,rehydration,hardness,microstructure,color difference,active ingredient anthocyanin,total phenol and DPPH radical scavenging capacity of dried blueberries in different treatment groups under hot air drying were compared and analyzed.The results showed that the dehydration rates of blueberries vary greatly according to the type of pretreatments when the samples were dried to the same water content with hot air.Specifically,the dehydration rate of dried blueberries pretreated by 5.0%K2CO3 solution was the highest,followed by 2.5%K2CO3 osmotic pretreatment and lastly the control group;the corresponding dehydration time was 10,14 and 20h,respectively.The physical qualities of dried blueberries,involving the browning degree,color difference,rehydration and microstructure,were significantly different between the chemical osmotic pretreatment group and the control group(P<0.05).The chemical osmotic pretreatment of K2CO3 solution increased the dehydration rate of the samples,shortened the drying time and maintained the quality of blueberries dried with hot air.There was no significant difference between the physical quality of dried blueberries pretreated by 2.5%and 5.0%K2CO3 solution(P>0.05),whereas there was significant difference in drying time and nutrient quality which is characterized by total phenols,anthocyanins,DPPH radical scavenging rate,soluble total sugar(P<0.05).Conclusion:5.0%K2CO3 osmotic pretreatment combining with hot air drying can improve the dehydration rate,shorten the drying time and maintain the physical and nutritional quality.

Liquid penetration of freeze-drying and air-drying wood of plantation Chinese fir

A comparative study was conducted on liquid penetration of the freeze-drying and air-drying sapwood and heartwood lumber of plantation Chinese fir （Cunninghamia lanceolata）. The maximum amount of dyeing solution uptake by the capillary rise method was used to evaluate the liquid penetration properties of the treated wood. The pit aspiration ratio was determined by semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results showed that compared with air drying, the freeze drying had a significant effect on liquid penetration of sapwood and heartwood of Chinese fir. The liquid penetration of sapwood is significantly higher than that of the heartwood for both drying treatments. Low pit aspiration ratio and cracks of pits membrane of some bordered pits are the main reasons for increasing liquid penetration after freeze drying treatment.

Parameter optimization for microwave coupled with hot air drying process of hawthorn slices using response-surface methodology

The microwave coupled with hot air(MCHA)drying method was used in this test to dry hawthorn slices The effect of initial microwave power density level(6 W/g to 12 W/g),hot air temperature(55℃ to 70℃),and hot air velocity(1 m/s to 3 m/s)on the quality attributes of rehydration ratio(Rf),organic acid(OA)and ascorbic acid(AA)of the dehydrated hawthorn slices was analyzed using a response surface methodology.An orthogonal rotatable central composite with three factors and at five levels was used to develop predictive regression models for the responses.The prediction mathematical model of Rf,OA and AA of the hawthorn slice was determined by analysis of variance.Factor and response variables as well as the prediction mathematical model,the optimal drying process of Rf,OA and AA of the hawthorn slice were determined by using the Design-Expert software.The comprehensive optimal conditions were as follows:initial microwave power density 12 W/g,hot air temperature 55℃ and hot air velocity 1.56 m/s.

Optimization of hot air drying process for tiger nut and analysis of fatty acid composition of tiger nut oil

Hot air temperature,hot air humidity,and hot wind speed were selected as independent variables of quadratic orthogonal rotation combination test design through single factor test.Drying time,energy consumption,chromatism value,luminosity value,hardness,rehydration ratio,and other indexes of the product were used as the response value of the test.Response surface methodology(RSM)was used to analyze the effects of independent variables on the quality of tiger nut(Cyperus esculentus L.),and the process parameters were combined and optimized.The results show that the suitable technological conditions for hot air drying of tiger nut are as follows:hot air temperature of 63.15°C,hot air humidity of 44.92%,hot air wind speed of 2.48 m/s.Under these conditions,the product has the advantages of the short drying cycle,low energy consumption,good color and luster,low hardness and good rehydration performance.The fatty acid composition and content of tiger nut oil were determined by gas chromatography.The fatty acid composition and content of tiger nut oil were compared with those of soybean oil,olive oil,rapeseed oil and sesame oil,the results show that among the saturated fatty acids in tiger nut oil,palm oil had the highest content of 11.172%,which was between soybean oil and olive oil.The main composition of unsaturated fatty acids in tiger nut oil is oleic acid,with a content of 77.605%,which is 3.6 times higher than that of soybean oil,and even higher than that of olive oil.

Process performance and quality attributes of temperature and step-down relative humidity controlled hot air drying of Panax notoginseng roots

The effects of temperature and step-down relative humidity controlled hot-air drying(THC-HAD)on the drying kinetics,energy efficiency and quality,i.e.,rehydration ratio(RR),color parameters(L*,a*,b*),total color difference(ΔE*),Panax notoginseng saponins(PNS)content,and ginsenosides content(R1,Rg1,Re,Rd,Rb1)of Panax notoginseng roots were evaluated.The drying time was significantly affected by the drying temperature followed by the relative humidity(RH)of the drying air.Special combination of drying conditions,i.e.,drying temperature of 50°C,relative humidity of 40%for 3 h and then continuous dehumidification from 40%to 8%allowed to shorten the drying time by 25%compared to drying at the same temperature and continuous dehumidification.The longer was the drying time under constant high RH of drying air,the lower was the RR of dried samples.The step-down RH strategy contributed to the formation of a porous structure,enhancement of drying efficiency and quality improvement.Generally,the ginsenosides content increased with the increase in temperature,while no obvious trend was recorded for ginsenoside R1.The contents of the ginsenoside R1,Rg1,Rb1 and PNS decreased with the increase in the drying time under constant high RH.Taking into account the drying time,energy consumption and quality attributes,drying at the temperature of 50°C,constant RH of 40%for 3 h and then step-down RH from 40%to 8%was proposed as the most favorable combination of drying conditions for dehydration of whole Panax notoginseng roots.

Effects of combined infrared and hot-air drying on ginsenosides and drying characteristics of Panax notoginseng(Araliaceae)roots

Exploring new drying technology can help to deal with the challenge of better preservation of rhizome medicinal materials in the traditional Chinese medicine industry.In current work,combined infrared and hot-air drying(IR-HAD)was employed to Panax notoginseng roots and its effect on drying kinetics,energy efficiency and quality,i.e.,rehydration ratio(RR),color parameters(L^(*),a^(*),b^(*)),total color difference(ΔE),Panax notoginseng saponins(PNS)content,and ginsenosides content(R_(1),R^(g1),R_(e),R_(d),R_(b1))were evaluated.Hot air drying(HAD)was used as the control.Results showed that the increase in drying temperature significantly shortened drying time and reduced energy consumption.The shortest drying time of 43.0 h and lowest specific energy consumption of 15.9 kW·h/(kg-water)were obtained by IR-HAD at 55°C.The decrease of radiation distance and the increase of radiation power led to the shortening of drying time.However,high drying temperature resulted in largeΔE values,large collapse structure,and RR of samples.The drying time of Panax notoginseng roots dried by IR-HAD at a drying temperature of 50°C was shorter(15.5%)than HAD dried at the same drying temperature.The contents of R_(1),R_(g1),R_(e),R_(b1),and PNS were higher when the samples were dried by IR-HAD than those dried by HAD at the same temperature of 50°C.Moreover,the IR-HAD dried samples shortened 15.5%drying time and saved 22.1%energy consumption compared with HAD.Therefore,the optimal process condition was Panax notoginseng roots under IR-HAD at drying temperature of 50°C,radiation distance of 12 cm and radiation power of 1350 W,which can shorten drying time,maintain high ginsenosides contents and satisfactory apparent qualities.

Effects of hot air drying temperature and tempering time on the properties of maize starch

Yellow maize as raw materials,hot air drying was used to reduce moisture content,and the tempering was implemented after drying.This study aimed to investigate the effects of hot air drying temperature and tempering time on the properties of maize starch.The wet milling was used to extract maize starch.Starch yield,protein content,amylose and amylopectin content,transparency and coagulation,solubility index and swelling power,color,pasting properties,and gelatinization properties were researched.The results showed that when the hot air temperature increased,the properties such as starch yield,amylopectin content,transparency,solubility,swelling power,whiteness decreased,and properties such as protein content and amylose content,coagulation,gelatinization temperature increased.Compared to drying temperature,tempering time has a less remarkable effect on the maize starch properties.The maize starch with better whiteness,solubility,swelling power could be obtained by adjusting tempering time.

Effect of different drying methods on the taste and volatile compounds,sensory characteristics of Takifugu obscurus

Pufferfish is prone to deterioration due to abundant nutrients and high moisture content.Drying technology can extend the shelf life and enhance the flavor quality of aquatic products.The study investigated the effect of hot air drying(HAD),microwave vacuum drying(MVD)and hot air assisted radio frequency drying(HARFD)on the taste and volatile profiles of Takifugu obscurus.Different drying methods had significant influence on the color,rehydration,5’-nucleotides,free amino acids and volatile components(P<0.05).The results showed that HAD and HARFD could promote the flavor of T.obscurus by producing higher equivalent umami concentration(EUC)values,which were about two times of MVD group,and more pronounced pleasant odor according to sensory analysis.HAD is more appropriate for industrial application than HARFD and MVD considering the economic benefits.This study could provide a reference for the industrial application of drying T.obscurus.

Effect of air drying on speciation of heavy metals in flooded rice paddies

Flooded soil samples were collected in the typical area of the Yangtze Delta Region; fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry. In flooded soils, fractions of heavy metals increased in the order of acid soluble 〈 oxidizable 〈 reducible 〈 residual. The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried. The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.

Effects of Different Drying Processes on the Effective Components of Stichopus japonicus Viscera

Drying is a basic link in seafood processing, and the effects of forced air drying and vacuum drying on the effective components of Stichopus japonicus viscera were compared with the moisture, total saponin and polysaccharide contents as the detection indexes. The contents of effective components obtained using forced air drying were slightly lower than those obtained using vacuum drying, but the forced air drying method used short drying time and low economic energy consumption. Excellent drying effects and low cost of forced air drying made it can be adapted to the requirements of large-scale production applications.

Influence of Different Drying Temperatures on Quality of Balsam Pear Slices

[Objective] The aim was to investigate the effects of different drying temperatures on the physiochemical properties and antioxidant activity of balsam pear slices. [Method] Balsam pear slices were dried at different hot air temperatures, 40, 50, 60, 70 and 80 ℃. [Result] The polyphenols content was highest （2.83 mg/g） in the balsam pear slices dried at 50 ℃, and the flavonoids content was highest （2.584 mg/g） in those dried at 60 ℃. Different drying temperatures had a great impact on the antioxidant capacity of polyphenols in balsam pear. The balsam pear slices dried at 50 ℃ showed the strongest capacity for scavenging DPPH free radicals with IC50 of 0.015 mg/ml, and those dried at 80 ℃ showed the strongest capacity for removing ABTS free radicals with IC50 of 0.0689 mg/ml. [Conclusion] The hot air temperature of 50 ℃ had the least impact on the quality of balsam pear slices.

Genetic Control of Air-Dried Wood Density, Mechanical Properties and Its Implication for Veneer Timber Breeding of New Triploid Clones in Populus tomentosa Carr

The wood samples of 9 triploid clones of Populus tomentosa Carr. taken from a 9 year old clonal test site were analyzed in order to investigate the genetic variation of wood properties, including air dried wood density and some mechanical properties. The results showed that significant or extremely significant difference in air dried wood density and the mechanical properties existed among the clones, this means these wood properties were under moderate or strong genetic controls and could be improved by genetic manipulations. The radial and vertical variation patterns of air dried wood density were also studied and the results were found to coordinate with other previous research results. The vertical variation patterns of most mechanical properties within the individual tree also conformed to the general wood theories except the modulus of elasticity and cross section hardness. Among the mechanical properties, modulus of elasticity (MOE) and tangent section hardness were under strong genetic control, with the clonal repeatabilities being 0 90 and 0 80, respectively. However, the clonal repeatabilities of other mechanical properties under study were a little lower than above two indexes. Genetic correlation analysis indicated that super clonal selection and breeding for veneer timber could be realized through indirect selection of wood density and form indexes.

The Influence of Drying Temperature and Extraction Methods on a-Mangostin in Mangosteen Pericarp

The effects of drying temperature and extraction methods on α-mangostin content in mangosteen pericarp （Garcinia mangostana L.） powder were investigated. In the first part of experiment suitable drying temperature for retention α-mangostin content was determined. Three levels of drying temperatures （55, 65 and 75 ℃） were used in this study. The drying rates were increased with drying temperature. Room temperature extraction method was performed to investigate the effect of drying temperature on retention α-mangostin content in mangosteen pericarp. The α-mangostin content extracted at three different drying temperatures （55, 65 and 75 ℃） was 35.98 ± 0.49%, 40.32 ± 0.24%, and 37.79±0.34% w/w, respectively. The results showed that the suitable temperature for drying mangosteen pericarp was 65 ℃ that gave the highest of α-mangostin content. The second part of experiment was the comparison between extraction methods, such as shaking water bath extraction （SWE）, soxhlet extraction （SE） and microwave-assisted extraction （MAE）. The results show that MAE gave the highest extraction rate and α-mangostin content as compare to SWE and SE. The α-mangostin content extraction from SWE, SE and MAE are 45.83 ± 0.02, 34.82± 0.17 and 49.79 ± 0.15% w/w of crude extract, respectively.

Analysis of the Influence of Different Drying Methods on the Active Ingredients of Fresh Medicine

The heating area of the material is large and the thermal efficiency is high,but it is n ecessary to control the suitable drying temperature ofdiffere nt medici nal materials to preserve the effective in gredients.D iff ere nt kinds of Chinese medicine need different drying conditions to fulfill good drying requirements.Natural drying in the shade is one of the traditional drying methods,which takes a long time and is easily affected by the weather.The water volatilizes slowly.It is prone to mildew and discoloration during the drying process.However,it can better preserve the volatile oil components of Chinese medicine.The hot-air drying machine has lower requirements.The medicinal materials have a large heating area and high thermal efficiency,but it is necessary to control the appropriate drying temperature of different medicinal materials in order to preserve the active ingredients of the medicinal materials;it is not suitable for medicinal materials that stick and bind easily.The microwave drying method possesses superiority in drying some valuable medicinal materials such as Ren she n(Radix et Rhizoma Ginseng)and Lurong(Co「nu Cervi Pantotrichum),and the effective ingredients are preserved at a high degree;it can also achieve the purpose of killing enzymes and protecting glycosides and have a good bactericidal effect,but it is not suitable for Chinese medicines containing heat-sensitive ingredients,because it will destroy most of the proteins,amino acids,and peptides of Chinese medicine and result in the loss of efficacy.The far-infrared drying method is suitable for drying thin-layer medicinal materials and is friendly to the environment.Freeze-drying can preserve the active ingredients very well and greatly retain the efficacy,but it has obvious limitations in preserving some Chinese medicinal materials that need to kill enzymes and protect glycosides;besides,the cost is relatively high and the drying time is long.

Physico-chemical properties and nutrition quality of potato flour: chuño vs modern processing technology

Chuño production is a kind of ancient method of potato preservation that has been used to the present day.In this study,physicochemical property and nutrition quality of white chuño(WC),black chuño,and dehydrated potato flour prepared by hot air drying(AD)and freezing drying were analyzed and compared.The results revealed that the average particle size of the starch in WC is almost 10 times of the dehydrated potato flour by AD treatment according to the laser particle size meter.During the dehydration of WC,water-soluble minerals(K+,Mg2+),proteins,ascorbic acid,etc.were partly lost while Ca2+content increased dramatically.In addition,WC showed the lowest antioxidant capacity among the four different kinds of dehydrated potato products.The polyphenol oxidase activity of WC,black chuño and AD were between 0.62–12.2 U/g fresh weight,which indicated that the color will be stable when chuño was used as staple food ingredient in the subsequent process.Therefore,as a potato processed food,chuño displayed great potential for promotion in the cold and poor rural areas of the northern China.

Physiological characteristics changes of Aesculus chinensis seeds during natural dehydration

A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase （SOD） activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde （MDA） content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.

Dry Intrusion Analysis of A Heavy Rainstorm in Southern Shaanxi

[Objective] One regional rainstorm weather in the south area of Shaanxi was expounded.[Method] By employing the NCEP/NCAR 1°×1°reanalysis data,routine observation and automatic precipitation station data,the large scale circulation background field of regional precipitation in the south area of Shaanxi province from July 16-18 in 2010 was expounded.By dint of physical quantity such as the meridional wind,relative humidity and false relative temperature,the characteristics of dry intrusion and its role in rainstorm were expounded.[Result] The mild and high latitude at 500 hPa was stable.The continental high pressure and subtropical high pressure were stable.The 700 and 850 hPa shear lines or low vortexes were the main influence system that resulted into large scale of rainstorm in south Shaanxi.The landing typhoon had distinct influences on the importance of storm.The influence of typhoon and subtropical high was mutual.It not only formed and strengthened the torrent in the low air,also transmitted water vapor and energy incessantly to the south area of Shaanxi,playing an important role in augment of rainstorm.There were two distinct dry intrusions in the rainstorm process,showing a dense dry layer in the high layer of convective layer.The existence of dry layer was conductive to the accumulation of convective unstable energy in the low layer.The release of convective unstable energy could transmit warm and wet airstream in the low level to the higher level,being conductive to the occurrence of precipitation.The analysis of θse in the warp direction vertical profile suggested that there was frontal zone in this rainstorm process and the dry air activity in this rainstorm process was very strong.[Conclusion] The study provided theoretical reference to the forecast in future.

ANFIS and ANNs model for prediction of moisture diffusivity and specific energy consumption potato,garlic and cantaloupe drying under convective hot air dryer

The main purpose of this study was to develop and apply an adaptive neuro-fuzzy inference system(ANFIS)and Artificial Neural Networks(ANNs)model for predicting the drying characteristics of potato,garlic and cantaloupe at convective hot air dryer.Drying experiments were conducted at the air temperatures of 40,50,60 and 70
C and the air speeds of 0.5,1 and l.5 m/s.Drying properties were including kinetic drying,effective moisture diffusivity(Deff)and specific energy consumption(SEC).The highest value of Deff obtained 9.76×10^-9,0.13×10^-9 and 9.97×10^-10 m^2/s for potato,garlic,and cantaloupe,respectively.The lowest value of SEC for potato,garlic,and cantaloupe were calculated 1.94
105,4.52
105 and 2.12
105 kJ/kg,respectively.Results revealed that the ANFIS model had the high ability to predict the Deff(R^2=0.9900),SEC(R^2=0.9917),moisture ratio(R^2=0.9974)and drying rate(R^2=0.9901)during drying.So ANFIS method had the high ability to evaluate all output as compared to ANNs method.

Effects of air movement in a hot air dryer on the drying characteristics of colored potato (Solanum tuberosum L.) using computational fluid dynamics

The flow fields of hot air in the dryer for drying colored potatoes of which characteristics are highly sensitive to the temperature were simulated using computational fluid dynamics(CFD)simulation.The local air velocity decreased as the distance from the flow inlet increased.The mass and heat transfer coefficients increased from 0.666×10^(-2) m/s to 1.711×10^(-2) m/s,and 6.555 W/(m^(2)·K)to 16.834 W/(m^(2)·K),respectively,as the air velocity increased from 0.207 m/s to 1.567 m/s at 60°C.The drying simulation model using the heat and mass transfer model made accurate predictions.The thermal properties of colored potato,such as the thermal conductivity and specific heat,decreased significantly from 0.440 W/(m·K)to 0.034 W/(m·K)and 3906.45 J/(kg·K)to 2198.52 J/(kg·K),respectively,as the moisture content decreased from 78% to 5%.With the variable thermal and physical properties,the heat transfer simulation model made accurate predictions of the hot-air drying characteristics for the colored potatoes,and the RMSE values for all cases were(1.85±0.27)℃.