苦瓜片气体射流冲击干燥特性及干燥模型
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摘要
【目的】提高苦瓜片的干制品质、缩短干燥时间,通过研究不同条件下气体射流冲击技术对苦瓜片干燥特性的影响,并根据干燥过程中水分的变化规律确定最适干燥模型。【方法】利用实验室自制气体射流冲击干燥机干燥苦瓜片,探讨不同风温(40、50、60、70和80℃)、风速(9、10、11、12和13 m·s~(-1))和切片厚度(2、3、4、5和6 mm)对物料干燥特性和水分有效扩散系数的影响,计算出干燥活化能。以确定系数(R~2)、卡方(χ~2)及均方根误差(RMSE)为评价指标,并利用Origin 8.0软件将试验所得数据与5个常用的干燥模型进行拟合,筛选出最适干燥模型,建立模型参数与干燥条件之间的关系,并检验干燥模型的预测效果。【结果】苦瓜片的气体射流冲击干燥属于降速干燥,没有明显的恒速干燥阶段。在试验条件下,风温、风速和切片厚度对苦瓜片在气体射流冲击干燥过程中的干燥特性均有一定影响,风温越大、切片厚度越小、风速越大,物料的干燥速率越大,水分比下降越快,干燥所需时间越短,但风速的影响远不如风温和切片厚度明显。通过费克第二定律可以计算出苦瓜片在干燥过程中的水分有效扩散系数,且随着风温、风速和切片厚度的增加而增加,最高的有效扩散系数为2.9668×10~(-9) m~2·s~(-1)。通过阿伦尼乌斯公式可以计算出苦瓜片干燥过程中所需的活化能Ea为29.89 kJ·mol~(-1)。所选的5个模型均具有较高的拟合度(R~2>0.98),都能较好的预测苦瓜片在气体射流冲击干燥过程中水分的变化规律,其中Two term exponential模型具有最大的确定系数R~2(0.99937)、最小的卡方值χ~2(0.00876)和均方根误差RMSE(0.000077),是苦瓜片气体射流冲击干燥的最适模型。【结论】风温、风速和切片厚度对苦瓜片气体射流冲击干燥过程中的干燥曲线、干燥速率曲线和水分扩散系数均有影响,且风温>切片厚度>风速。在风温40—80℃,风速9—13 m·s~(-1),切片厚度2—6 mm范围内,Two term exponential模型的拟合度最高,模型可有效描述苦瓜片在气体射流冲击干燥过程中的水分变化规律。
【Objective】In order to improve the drying quality of the bitter melon slice(BMS), shorten the drying time, the effects of the air-impingement drying conditions on the drying characteristics of the BMS were studied and the drying kinetics model was established to predict the moisture change in the drying process. 【Method】The BMS were dried by the air-impingement jet dryer made by the authors' laboratory. The effects of different air temperatures(40, 50, 60, 70 and 80℃), air velocities(9, 10, 11, 12 and 13 m·s~(-1)) and slice thickness(2, 3, 4, 5 and 6 mm) on the drying characteristics of materials and effective moisture diffusion coefficient of water were studied, and the activation energy was calculated. With the R~2, χ~2 and RMSE as the evaluation indexes, the optimum model was screened within the five commonly used dry models fitting the experimental data by Origin 8.0 software, then the relationships between the model parameters and drying conditions was establish and the prediction effect of the optimum drying model was verified.【Result】The air-impingement jet drying of BMS occurred in the falling rate drying period, and there was no constant drying rate stage. Under the experimental condition, air temperature, air velocities and slice thickness all had a certain effect on dry characteristics of BMS in air-impingement jet drying process. With the increase of air temperature and air velocities, the decrease of the slice thickness, the moisture of material decreased more fast and the drying rate was rising, the drying time was short, but the influence of air velocities was less significant than air temperature and slice thickness. The water effective diffusion coefficient of the BMS during drying process could be calculated by Fick's second law, and it increased with the increase of air temperature, air velocities and slice thickness. The maximum effective diffusion coefficient was 2.9668×10-9 m2·s~(-1). Arrhenius was used to calculate the activation energy of BMS in drying process and the value of Ea was 29.89 k J·mol~(-1). The five selected models all had good fitness(R~2>0.98), they could predict the moisture change of the BMS in air-impingement jet drying process. Of the five models, the Two term exponential model had the highest coefficient of determination R~2(0.99937), the lowest chi-square χ~2(0.00876) and root mean square RMSE(0.000077), and it is the optimum model of the BMS in air-impingement jet drying. 【Conclusion】All the factors including the air temperature, air velocities and slice thickness had influence on the drying curve, the drying rate curve and moisture effective diffusion coefficient, and their influences were in an order of the air temperature>air velocities>slice thickness. Two term exponential model could properly describe the air-impingement jet drying behavior of BMS and could be used to predict the moisture change of the BMS in air-impingement jet drying process under the condition that the air temperatures between 40 and 80℃, air velocities between 9 and 13 m·s~(-1) and slice thickness between 2 and 6 mm.
【Objective】In order to improve the drying quality of the bitter melon slice(BMS), shorten the drying time, the effects of the air-impingement drying conditions on the drying characteristics of the BMS were studied and the drying kinetics model was established to predict the moisture change in the drying process. 【Method】The BMS were dried by the air-impingement jet dryer made by the authors' laboratory. The effects of different air temperatures(40, 50, 60, 70 and 80℃), air velocities(9, 10, 11, 12 and 13 m·s~(-1)) and slice thickness(2, 3, 4, 5 and 6 mm) on the drying characteristics of materials and effective moisture diffusion coefficient of water were studied, and the activation energy was calculated. With the R~2, χ~2 and RMSE as the evaluation indexes, the optimum model was screened within the five commonly used dry models fitting the experimental data by Origin 8.0 software, then the relationships between the model parameters and drying conditions was establish and the prediction effect of the optimum drying model was verified.【Result】The air-impingement jet drying of BMS occurred in the falling rate drying period, and there was no constant drying rate stage. Under the experimental condition, air temperature, air velocities and slice thickness all had a certain effect on dry characteristics of BMS in air-impingement jet drying process. With the increase of air temperature and air velocities, the decrease of the slice thickness, the moisture of material decreased more fast and the drying rate was rising, the drying time was short, but the influence of air velocities was less significant than air temperature and slice thickness. The water effective diffusion coefficient of the BMS during drying process could be calculated by Fick's second law, and it increased with the increase of air temperature, air velocities and slice thickness. The maximum effective diffusion coefficient was 2.9668×10-9 m2·s~(-1). Arrhenius was used to calculate the activation energy of BMS in drying process and the value of Ea was 29.89 k J·mol~(-1). The five selected models all had good fitness(R~2>0.98), they could predict the moisture change of the BMS in air-impingement jet drying process. Of the five models, the Two term exponential model had the highest coefficient of determination R~2(0.99937), the lowest chi-square χ~2(0.00876) and root mean square RMSE(0.000077), and it is the optimum model of the BMS in air-impingement jet drying. 【Conclusion】All the factors including the air temperature, air velocities and slice thickness had influence on the drying curve, the drying rate curve and moisture effective diffusion coefficient, and their influences were in an order of the air temperature>air velocities>slice thickness. Two term exponential model could properly describe the air-impingement jet drying behavior of BMS and could be used to predict the moisture change of the BMS in air-impingement jet drying process under the condition that the air temperatures between 40 and 80℃, air velocities between 9 and 13 m·s~(-1) and slice thickness between 2 and 6 mm.
引文
[1]朱群娣,吴康郁,袁伟彬.苦瓜中总皂苷的比色法测定.中医学报,2014,29(10):1469-1472.ZHU Q D,WU K Y,YUAN W B.Colorimetric method determination of total saponins from Momordica Charantia L.China Journal of Chinese Medicine,2014,29(10):1469-1472.(in Chinese)
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[3]朱香燕,张珺,何义雁,邓放明.热风与远红外干燥温度对苦瓜全粉品质的影响.现代食品科技,2015,31(7):265-269,325.ZHU X Y,ZHANG J,HE Y Y,DENG F M.Effects of hot air and far-infrared drying temperatures on quality Of bitter gourd(Momordica charantia L.)powder.Modern Food Science and Technology,2015,31(7):265-269,325.(in Chinese)
[4]SARKAR S,PRANAVA M,MARIT A R.Demonstration of the hypoglycemic action of Momordica Charantia in a validated animal model of diabetes.Pharmacological Research,1996,33(1):1-4.
[5]REYES B A S,BAUTISTA N C,TANQUILUT R V,ANUNCIADO A B,LEUNG G C,SANCHEZ R L,MAGTOTO P,CASTRONUEVO H,TSUKAMURA K,MAEDA.Anti-diabetic potentials of Momordica charantia and Andrographis paniculata and their effects on estrous cyclicity of alloxan-induced diabetic rats.Journal of Ethnopharmacology,2006,105(1/2):196-200.
[6]GUEVAR A P,LIM-SYLIANCO C,DAYRIT F,FINCH P.Antimutagens from Momordica charantia.Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis,1990,230(2):121-126.
[7]SINGH A,SINGH S P,BAMEZAI R.Momordica charantia(Bitter Gourd)peel,pulp,seed and whole fruit extract inhibits mouse skin papillomagenesis.Toxicology Letters,1998,94(1):37-46.
[8]华中农业大学.蔬菜贮藏加工学.北京:中国农业出版社,2001.Huazhong Agricultural University.Vegetable Storage Processing.Beijing:China Agriculture Press,2001.(in Chinese)
[9]高振江.气体射流冲击颗粒物料干燥机理与参数试验研究[D].北京:中国农业大学,2000.GAO Z J.Experimental research on mechanism and parameter of air-impingement jet drying of particulate Materials[D].Beijing:China Agricultural University,2000.(in Chinese)
[10]李文峰,肖旭霖,王玮.紫薯气体射流冲击干燥效率及干燥模型的建立.中国农业科学,2013,46(2):356-366.LI W F,XIAO X L,WANG W.Drying characteristics and model of purple sweet potato in air-impingement jet dryer.Scientia Agricultura Sinica,2013,46(2):356-366.(in Chinese)
[11]汤琴.不同干制方式苦瓜茶的品质差异及其“降火”相关活性[D].武汉:华中农业大学,2014.TANG Q.Quality differences and“Jianghuo”effects of different drying method on Momordica Charantia L[D].Wuhan:Huazhong Agricultural University,2014.(in Chinese)
[12]王华红.苦瓜切片热风干燥特性及含水率预测模型研究[D].呼和浩特:内蒙古农业大学,2013.WANG H H.Sliced bitter melon’s hot air drying characteristics and moisture prediction model research[D].Hohhot:Inner Mongolia Agricultural University,2013.(in Chinese)
[13]杨文侠,高振江,谭红梅,杨洋,陈曾,肖红伟.气体射流冲击干燥无核紫葡萄及品质分析.农业工程学报,2009,25(4):237-242.YANG W X,GAO Z J,TAN H M,YANG Y,CHEN Z,XIAO H W.Drying Monukka grapes with air-impingement jet technique and quality analysis.Transactions of the CSAE,2009,25(4):237-242.(in Chinese)
[14]张茜,肖红伟,代建武,杨旭海,白竣文,娄正,高振江.哈密瓜片气体射流冲击干燥特性和干燥模型.农业工程学报,2011,27(S1):382-388.ZHANG Q,XIAO H W,DAI J W,YANG X H,BAI J W,LOU Z,GAO Z J.Air impingement drying characteristics and drying model of Hami melon flake.Transactions of the CSAE,2011,27(Supp.1):382-388.(in Chinese)
[15]肖红伟,张世湘,白竣文,方小明,张泽俊,高振江.杏子的气体射流冲击干燥特性.农业工程学报,2010,26(7):318-323.XIAO H W,ZHANG S X,BAI J W,FANG X M,ZHANG Z J,Gao Z J.Air impingement drying characteristics of apricot.Transactions of the CSAE,2010,26(7):318-323.(in Chinese)
[16]XIAO H W,GAO Z J,LIN H,YANG WX.Air impingement drying characteristics and quality of carrot cubes.Journal of Food Process Engineering,2010,33(5):899-918.
[17]姚雪东,肖红伟,高振江,田松涛,杜荣.气流冲击式转筒干燥机设计与试验.农业机械学报,2009,40(10):67-70.YAO X D,XIAO H W,GAO Z J,TIAN S T,DU R.Design and experiment of air-impingement rotary dryer.Transactions of the CSAE,2009,40(10):67-70.(in Chinese)
[18]娄正,高振江,肖红伟,王晓拓,李伟,孙新超.板栗气体射流冲击干燥特性和工艺优化.农业工程学报,2010,26(11):368-373.LOU Z,GAO Z J,XIAO H W,WANG X T,Li W,SUN X C.Air impingement drying characteristics and process optimization of chestnut.Transactions of the CSAE,2010,26(11):368-373.(in Chinese)
[19]张建,赵武奇,肖旭霖,黄小丽,吴忠,赵雪萌.板桥党参片气体射流冲击干燥工艺及干燥模型.中药材,2016,39(3):534-539.ZHANG J,ZHAO W Q,XIAO X L,HUANG X L,WU Z,ZHAO X M.Drying process and model of Banqiao Codonopsis radix slice in air-impingement jet dryer.Journal of Chinese Medicinal Materials,2016,39(3):534-539.(in Chinese)
[20]DOYMAZ I.Air-drying characteristics of tomatoes.Journal of Food Engineering,2007,78(4):1291-1297.
[21]ERTEKIN C,YALDIZ O.Drying of eggplant and selection of a suitable thin layer drying model.Journal of Food Engineering,2004,63(3):349-359.
[22]O’CALLAGHAN J R,MENZIES D J,BAILEY P H.Digital simulation of agricultural dryer performance.Journal of Agricultural Engineering Research,1971,16(3):223-244.
[23]FALADE K O,SOLADEMI O J.Modelling of air drying of fresh and blanched sweet potato slices.International Journal of Food Science and Technology,2010,45(2):278-288.
[24]WANG Z F,SUN J H,LILOX J,CHEN F,ZHAO G H,WU J H,HU X S.Mathematical modeling on hot air Drying of thin layer apple pomace.Food Research International,2007,40(1):39-46.
[25]WHITE G M,ROSS I J,PONELER R.Fully exposed drying of popcorn.Transactions of the American Society of Agricultural Engineers,1981,24:466-468.
[26]BAINI R,LANGRISH T A G.Choosing an appropriate drying model for intermittent and continuous drying of bananas.Journal of Food Engineering,2007,79(1):330-343.
[27]CHKIR I,BALTI M A,AYEDA L,AZZOUZC S,KECHAOU N,HAMDI M.Effects of air drying properties on drying kinetics and stability of cactus/brewer’s grains mixture fermented with lactic acid bacteria.Food and Bioproducts Processing,2015,94:10-19.
[28]PURLIS E,SALVADORI V O.A moving boundary problem in a food material undergoing volume change-simulation of bread baking.Food Research International,2010,43(4):949-958.
[29]DOYMAZ?.Effect of dipping treatment on air drying of plums.Journal of Food Engineering,2004,64(4):465-470.
[30]WANG R,ZHANG M,MUJUMDAR A S,SUN J C.Microwave freeze-drying characteristics and sensory quality instant vegetable soup.Drying Technology,2009,27(9):962-968.
[2]鲁允.苦瓜的加工利用.农产品加工(学刊),2006(7):41-43,46.LU Y.Processing and utilization of bitter gourd.Academic Periodical of Farm Products Processing,2006(7):41-43,46.(in Chinese)
[3]朱香燕,张珺,何义雁,邓放明.热风与远红外干燥温度对苦瓜全粉品质的影响.现代食品科技,2015,31(7):265-269,325.ZHU X Y,ZHANG J,HE Y Y,DENG F M.Effects of hot air and far-infrared drying temperatures on quality Of bitter gourd(Momordica charantia L.)powder.Modern Food Science and Technology,2015,31(7):265-269,325.(in Chinese)
[4]SARKAR S,PRANAVA M,MARIT A R.Demonstration of the hypoglycemic action of Momordica Charantia in a validated animal model of diabetes.Pharmacological Research,1996,33(1):1-4.
[5]REYES B A S,BAUTISTA N C,TANQUILUT R V,ANUNCIADO A B,LEUNG G C,SANCHEZ R L,MAGTOTO P,CASTRONUEVO H,TSUKAMURA K,MAEDA.Anti-diabetic potentials of Momordica charantia and Andrographis paniculata and their effects on estrous cyclicity of alloxan-induced diabetic rats.Journal of Ethnopharmacology,2006,105(1/2):196-200.
[6]GUEVAR A P,LIM-SYLIANCO C,DAYRIT F,FINCH P.Antimutagens from Momordica charantia.Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis,1990,230(2):121-126.
[7]SINGH A,SINGH S P,BAMEZAI R.Momordica charantia(Bitter Gourd)peel,pulp,seed and whole fruit extract inhibits mouse skin papillomagenesis.Toxicology Letters,1998,94(1):37-46.
[8]华中农业大学.蔬菜贮藏加工学.北京:中国农业出版社,2001.Huazhong Agricultural University.Vegetable Storage Processing.Beijing:China Agriculture Press,2001.(in Chinese)
[9]高振江.气体射流冲击颗粒物料干燥机理与参数试验研究[D].北京:中国农业大学,2000.GAO Z J.Experimental research on mechanism and parameter of air-impingement jet drying of particulate Materials[D].Beijing:China Agricultural University,2000.(in Chinese)
[10]李文峰,肖旭霖,王玮.紫薯气体射流冲击干燥效率及干燥模型的建立.中国农业科学,2013,46(2):356-366.LI W F,XIAO X L,WANG W.Drying characteristics and model of purple sweet potato in air-impingement jet dryer.Scientia Agricultura Sinica,2013,46(2):356-366.(in Chinese)
[11]汤琴.不同干制方式苦瓜茶的品质差异及其“降火”相关活性[D].武汉:华中农业大学,2014.TANG Q.Quality differences and“Jianghuo”effects of different drying method on Momordica Charantia L[D].Wuhan:Huazhong Agricultural University,2014.(in Chinese)
[12]王华红.苦瓜切片热风干燥特性及含水率预测模型研究[D].呼和浩特:内蒙古农业大学,2013.WANG H H.Sliced bitter melon’s hot air drying characteristics and moisture prediction model research[D].Hohhot:Inner Mongolia Agricultural University,2013.(in Chinese)
[13]杨文侠,高振江,谭红梅,杨洋,陈曾,肖红伟.气体射流冲击干燥无核紫葡萄及品质分析.农业工程学报,2009,25(4):237-242.YANG W X,GAO Z J,TAN H M,YANG Y,CHEN Z,XIAO H W.Drying Monukka grapes with air-impingement jet technique and quality analysis.Transactions of the CSAE,2009,25(4):237-242.(in Chinese)
[14]张茜,肖红伟,代建武,杨旭海,白竣文,娄正,高振江.哈密瓜片气体射流冲击干燥特性和干燥模型.农业工程学报,2011,27(S1):382-388.ZHANG Q,XIAO H W,DAI J W,YANG X H,BAI J W,LOU Z,GAO Z J.Air impingement drying characteristics and drying model of Hami melon flake.Transactions of the CSAE,2011,27(Supp.1):382-388.(in Chinese)
[15]肖红伟,张世湘,白竣文,方小明,张泽俊,高振江.杏子的气体射流冲击干燥特性.农业工程学报,2010,26(7):318-323.XIAO H W,ZHANG S X,BAI J W,FANG X M,ZHANG Z J,Gao Z J.Air impingement drying characteristics of apricot.Transactions of the CSAE,2010,26(7):318-323.(in Chinese)
[16]XIAO H W,GAO Z J,LIN H,YANG WX.Air impingement drying characteristics and quality of carrot cubes.Journal of Food Process Engineering,2010,33(5):899-918.
[17]姚雪东,肖红伟,高振江,田松涛,杜荣.气流冲击式转筒干燥机设计与试验.农业机械学报,2009,40(10):67-70.YAO X D,XIAO H W,GAO Z J,TIAN S T,DU R.Design and experiment of air-impingement rotary dryer.Transactions of the CSAE,2009,40(10):67-70.(in Chinese)
[18]娄正,高振江,肖红伟,王晓拓,李伟,孙新超.板栗气体射流冲击干燥特性和工艺优化.农业工程学报,2010,26(11):368-373.LOU Z,GAO Z J,XIAO H W,WANG X T,Li W,SUN X C.Air impingement drying characteristics and process optimization of chestnut.Transactions of the CSAE,2010,26(11):368-373.(in Chinese)
[19]张建,赵武奇,肖旭霖,黄小丽,吴忠,赵雪萌.板桥党参片气体射流冲击干燥工艺及干燥模型.中药材,2016,39(3):534-539.ZHANG J,ZHAO W Q,XIAO X L,HUANG X L,WU Z,ZHAO X M.Drying process and model of Banqiao Codonopsis radix slice in air-impingement jet dryer.Journal of Chinese Medicinal Materials,2016,39(3):534-539.(in Chinese)
[20]DOYMAZ I.Air-drying characteristics of tomatoes.Journal of Food Engineering,2007,78(4):1291-1297.
[21]ERTEKIN C,YALDIZ O.Drying of eggplant and selection of a suitable thin layer drying model.Journal of Food Engineering,2004,63(3):349-359.
[22]O’CALLAGHAN J R,MENZIES D J,BAILEY P H.Digital simulation of agricultural dryer performance.Journal of Agricultural Engineering Research,1971,16(3):223-244.
[23]FALADE K O,SOLADEMI O J.Modelling of air drying of fresh and blanched sweet potato slices.International Journal of Food Science and Technology,2010,45(2):278-288.
[24]WANG Z F,SUN J H,LILOX J,CHEN F,ZHAO G H,WU J H,HU X S.Mathematical modeling on hot air Drying of thin layer apple pomace.Food Research International,2007,40(1):39-46.
[25]WHITE G M,ROSS I J,PONELER R.Fully exposed drying of popcorn.Transactions of the American Society of Agricultural Engineers,1981,24:466-468.
[26]BAINI R,LANGRISH T A G.Choosing an appropriate drying model for intermittent and continuous drying of bananas.Journal of Food Engineering,2007,79(1):330-343.
[27]CHKIR I,BALTI M A,AYEDA L,AZZOUZC S,KECHAOU N,HAMDI M.Effects of air drying properties on drying kinetics and stability of cactus/brewer’s grains mixture fermented with lactic acid bacteria.Food and Bioproducts Processing,2015,94:10-19.
[28]PURLIS E,SALVADORI V O.A moving boundary problem in a food material undergoing volume change-simulation of bread baking.Food Research International,2010,43(4):949-958.
[29]DOYMAZ?.Effect of dipping treatment on air drying of plums.Journal of Food Engineering,2004,64(4):465-470.
[30]WANG R,ZHANG M,MUJUMDAR A S,SUN J C.Microwave freeze-drying characteristics and sensory quality instant vegetable soup.Drying Technology,2009,27(9):962-968.