بررسي آزمايشگاه و مدل سازي استخراج فوق بحراني اجزاءآنتي اكسيدان از گياه آلوئه ورا و بهينه سازي شرايط عملياتي با الگوريتم ژنتيك

چكيده انگليسي :

Experimental and Modeling Investigation of Supercritical Extraction ofAntioxidant Components from Aloe Vera and Optimization of Operation Conditions by Genetic Algorithm Fatemeh Bashipour f bashipoor@ce iut ac ir March 14 2011 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSeyyed Mohammad Ghoreishi ghoreshi@cc iut ac irAbstractSupercritical fluid extraction is powerful new technique in separation processes and environmentally is moreappropriate than crystallization adsorption chromatography and evaporation methods In this study organicsolvent extraction method and supercritical carbon dioxide extraction of Aloe vera plant was compared Aloevera leaves which are used traditionally for their therapeutic properties have been studied for their potentialantioxidant activity Aloe vera is rich of Alpha Tocopherol and Beta Carotene Beta Carotene that has highprovitamin A content is nutritionally essential to the human body Lack of this vitamin can lead to seriousdiseases such as night blindness etc Tocopherols are extremely valuable compounds because of theiractivity as vitamin E and capacity as anti oxidizing agent Alpha Tocopherol the most common form ofvitamin E present in nature is the most biologically active and is preferentially retained in large quantitiesand transported to body components Aim of these experiments was supercritical extraction of AlphaTocopherol and Beta Carotene from Aloe vera plant gel and skin respectively Other aims of this study weremathematical modeling of supercritical extraction and optimization of operating conditions Response surfacemethodology RSM and Genetic algorithm were applied to optimize effective operation conditions such astemperature pressure supercritical solvent flow rate and dynamic time In these experiments gel and skin ofthree year old Aloe vera Aloe barbadensis Miller leaf was used Separation of tocopherol from Aloe veraand the obtained results were compared with the conventional Soxhlet extraction 98 hexane 2 ethanol Alpha Tocopherol Soxhlet extraction from Aloe vera gel resulted 2 87 mg Alpha Tochopherol 100 gr drygel The same extraction technique from Aloe vera skin resulted 33 86 mg Beta Carotene 100 gr dry skin using petroleum ether as the solvent Design of experiments of Aloe vera gel supercritical extraction wasperformed on the temperature pressure carbon dioxide flow rate and dynamic time RSM experiments wereperformed at the following range of operating conditions 1 Temperature 40 60 C 2 Pressure 200 320bar 3 Superctitical solvent flow rate 0 5 1 5 ml CO2 min and 4 Dynamic time 60 140 min Theoptimum static time was determined to be 15 min and 0 6 mm of particle sizes were used The quadraticresponse surface model was obtained via the utilization of RSM central composite design CCD The resultsof this study demonstrated that flow rate of carbon dioxide had no significant effect on neither extracted oilyield nor recovery of Alpha Tocopherol The maximum tocopherol recovery was obtained with employingRSM predicted model for the optimum extraction operating conditions of 60 C 320 bar 0 5 ml CO2 min and140 min Similarly the maximum extraction yield was obtained with employing RSM predicted model forthe optimum extraction operating conditions of 57 8 C 32 Mpa 1 5 ml min and 140 min Moreover in thepresent study a mathematical modeling for extraction of Alpha Tocopherol and Beta Carotene from Aloevera plant gel and skin using supercritical carbon dioxide was performed The shrinking core model wasapplied to analyze the experimental results This model has been successfully applied in the process such assolid fluid reactions adsorption ion exchange and supercritical extraction of natural materials The modelsuccessfully fitted the experimental data for larger particle size Genetic algorithm was applied to determinethe optimal value of temperature pressure supercritical solvent flow rate and dynamic time Optimalextraction c

بشي پور، فاطمه

بررسي آزمايشگاه و مدل سازي استخراج فوق بحراني اجزاءآنتي اكسيدان از گياه آلوئه ورا و بهينه سازي شرايط عملياتي با الگوريتم ژنتيك

آلفاتوكوفرول , بتاكاروتن , رويه پاسخ , مدل سازي رياضي