بررسي آزمايشگاهي، مدل سازي و بهينه سازي استخراج فوق بحراني گليسيريزيك اسيد از ريشه ي گياه شيرين بيان

چكيده انگليسي :

037 Experimental Investigation Modeling and Optimization of Operating Conditions of Supercritical Extraction of Glycyrrhizic acid from licorice plant root Ali Hedayati ali hedayati@ce iut ac ir Date of submission 20 September 2015 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Prof Seyyed Mohammad Ghoreishi ghoreshi@cc iut ac irAbstractRecently scientists have proven the licorice therapeutic effects on various diseases such as cancer diabetes kidney stones inflammation ulcers skin diseases tuberculosis viral diseases respiratory diseases liver etc by extensive researches Licorice is composed of various compounds Most of its antioxidant effects are oftenattributed to glycyrrhizic acid GA Therefore necessity of GA extraction and producing extract ofantioxidant is obvious In this study the extraction of GA from licorice plant root was investigated bySoxhlet and modified supercritical CO2 extraction with different volume ratios of water and methanol asmodifier 30 min of static time and 07674 mm of average particle size Design of experiment carried out withresponse surface methodology RSM using Minitab 17 software The operating temperature 45 65 theoperating pressure 10 34 the dynamic extraction time 40 120 the flow rate of CO2 078 2 and methanolconcentration in methanol water binary entrainer 0 100 have been considered as operating variables Response surface analysis verified that the data were adequately fitted to second order polynomial model The linear terms of temperature pressure CO2 flow rate co solvent methanol concentration and dynamictime as well as quadratic terms of all variables except CO 2 flow rate had significant effects on the obtainedRSM model of GA recovery based on coded variables R2 and modified R2 of the model are 98705 and94751 respectively The maximum GA recovery of 5474 was predicted by the RSM model at the optimaloperating conditions of 2976 MPa 68oC 108 min dynamic time 2 ml min and 4675 methanolconcentration in binary modifier Moreover in the present study a mathematical modeling for GA extractionfrom licorice plant root was performed by modified supercritical carbon dioxide based on the differentialmass balance Mathematical model parameters are including effective pore diffusivity film mass transfercoefficient axial dispersion and distribution coefficient The first three parameters were obtained fromempirical equations and the distribution coefficient between solid and solvent has been determined byapplying the genetic algorithm to minimize the average absolute deviation AAD between the data obtainedfrom experiments and model equations In addition RSM was used to determine the effects of temperatureand pressure on the solubility S of GA in the supercritical fluid and co solvent so that we can use theobtained formula for Kp to put it in the mathematical model and finally determine the optimum operatingconditions The main process conditions which must be determined to maximize the extraction recovery aretemperature pressure flow rate of CO 2 and dynamic extraction time These were optimized by geneticalgorithm The optimal operating conditions were observed at 68 C 27719 MPa 1796 ml min and 119 min dynamic time to achieve 07338 recovery A three layer artificial neural network was also developed formodeling of GA extraction from licorice plant root In this regard different networks by changing thenumber of neurons in the hidden layer and algorithm of network training were compared with evaluation ofnetworks accuracy in extraction recovery prediction One step secant back propagation algorithm with sixneurons in hidden layer was found to be the most suitable network and the coefficient of determination R 2 was 9875 Key WordsGlycyrrhizic acid Supercritical extraction Co solvent Response surface methodology Mathematical modeling Genetic algorithm Neural network

هدايتي، علي

بررسي آزمايشگاهي، مدل سازي و بهينه سازي استخراج فوق بحراني گليسيريزيك اسيد از ريشه ي گياه شيرين بيان

اصلاحگر , طراحي رويه پاسخ , مدل سازي رياضي , الگوريتم ژنتيك , شبكه عصبي MLP