SUPERCRITICAL FLUID EXTRACTION OF TURMERIC ROOT AND CARROT SEED AND ITS ANALYSIS

Abstract

Supercritical fluid extraction (SFE) technology for the extraction of different type of species is gaining interest in food, pharmaceutical and chemical industries from last decades. Utilization of natural products, which are safe for humans and environment, is increasing day by day. Therefore, investigation of new natural products including plant extracts seems to be important. Further, due to increased public awareness for health, environmental and safety hazards associated with the use of organic solvents in extraction, SFE using supercritical CO2 provides necessary impetus to substitute petroleum based solvent such as hexane, ethers and chloroform, etc. In the present study, oils are extracted from Turmeric root and Carrot seed using SFE process where CO2 is utilized as supercritical solvent. These are used in pharmaceutical, cosmetics and food industry due to several medicinal effects. To extract oil experimental study is carried out using setup (SFE 1000F), procured from Thar Technologies Inc., Pittsburgh. Effects of five input parameters such as pressure, temperature, particle size, solvent flow rate and addition of co-solvent on the extraction yield (g oil/ g solid) are identified. Characterization of solid materials and their oils are performed through scanning electron microscopy (SEM), Thermo-gravimetric analysis (TGA), Differential thermal analysis (DTA), Differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR) spectroscopy. Physico-chemical properties such as refractive index, peroxide value, acid value, iodine value, saponification value, un-saponifiable matter, and specific gravity of oil samples are determined using standard methods of analysis. Essential oil and fatty acid composition of extracted oils are obtained using gas chromatography (GC), gas chromatography mass-spectroscopy (GC-MS) and ultra-violet (UV) spectroscopy. Full-face central composite design (CCD) is employed to optimize operating parameters of SFE of turmeric root oil. These parameters are pressure, temperature, solvent flow rate, particle size and addition of co-solvent (ethanol), which vary as 20-40 MPa, 40-60 °C, 5-15 g/min, 0.2-0.8mm and 0-15% of solvent rate, respectively. Turmeric oil yield found through Soxhlet extraction is 5.954 wt% of turmeric powder whereas through SFE, it varies from 2 to 5.3 wt%. Turmerone and Curcumin are identified as principle compounds of turmeric essential oil, which are analyzed using GC-MS and UV spectroscopy, respectively. Fatty acid analysis shows that oleic acid (cis and trans) is major monounsaturated fatty acid (MUFA) found in turmeric oil, which contributes 2.9 to 61.5% of turmeric oil followed by Linoleic acid (22.56%) and Linolenic acid (21.3%). Experimental data of oil yield, Curcumin content and Turmerone content are fitted well in the ii Quadratic model. Optimized values of operating parameters for maximizing these responses are also predicted. In the case of carrot seed, screening design is applied on pressure, temperature, solvent to feed ratio, particle size and co-solvent to study the contribution of each parameter on responses i.e. extraction oil yield (EOY) and Carotol content (CC). CCD is employed on reduced operating parameters where ranges are 20-40 MPa (pressure), 50-70 °C (temperature), 5-15 g/min (flow rate) and 0-10% of solvent to feed ratio(co-solvent). Extraction oil yield varies from 2.8 to 12.9 wt% of carrot seed using SFE process while it is 13.5 wt% for Soxhlet extraction. Operating parameters are optimized for maximizing both responses for SFE of carrot seed oil. Characterization of carrot seed and oil are also carried out using FTIR, SEM, TGA and DSC. Carotol and Daucol are found as primary compounds of carrot seed essential oil through GC-MS analyses, which contribute 82.19 to 94.09% and 0.53 to 5.85%, respectively, of carrot seed oil. Carrot seed oil comprises of 28 to 78% Oleic acid, which is the major MUFA of carrot seed oil. In addition, Pentadecylic acid, Margaric acid, γ-Linolenic acid, cis-Arachidic acid and cis-eicosatetraenoic acid are the USFA found in carrot seed oil. Further, effects of solute matrices such as leaves, flower concrete, flower bud, herb plant, shrub seed and vegetable matter are studied on extraction yield through different models. The models are solved using COMSOL Multiphysics 5.2 solver and results are validated with that of literature. Experimental data of each type of solute matrices are fitted in various models and best-suited model is predicted. Model proposed by Reverchon (1996) and Sovova (1994) are found suitable for leaves whereas Reverchon and Poletto (1996) and Reverchon et al. (2000) are suitable for flower and flowerhip seed, respectively. Reverchon (1996), Reverchon and Marrone (1997) and Sovova (1994) models are found suitable for flower bud. Further, Reverchon (1996) is well suited model for herb plant also. Model proposed by Reverchon (1996), Sovova (1994) and Nobre et al. (2006) are suitable models for shrub seed while, for vegetable matter, Sovova (1994) and Goto et al. (1996) are well suited model. Therefore, Sovova (1994) model is found suitable for most of the matrices. Experimental data of SFE of turmeric root and carrot seed oil are fitted in the model proposed by Sovova (1994) to validate experimental results. Oil yield of turmeric root is increasing with pressure from 200 to 300 bar and then decreasing for 400 bar. However, oil yield is increasing with temperature from 40 to 50 °C and then no significant effect is visible up to 60 °C. It is increasing with solvent flow rate whereas it is first increasing and then decreasing with increase in particle iii size and co-solvent. Models proposed by Sovova (1994) and Goto et al. (1996) are investigated as most suitable models for SFE of turmeric root oil while fitting experimental data of optimum points (300 bar, 60 °C, 15 g/min, 0.45 mm and 7.5%) into different models. On the other hand, oil yield of carrot seed is increased with pressure (400 bar) and temperature (70 °C) whereas, highest yield is observed at solvent flow rate of 10 g/min, and addition of co-solvent of 5% of solvent flow rate. Thus, these values of parameters are considered as optimum points and its experimental data is fitted into different models. Consequently, models proposed by Sovova (1994) and Reverchon and Marrone (1997) are found most suitable for SFE of carrot seed oil. Industrial-scale economic assessment of SFE process is carried out considering 60 t/y and 120 t/y production capacities for turmeric root and carrot seed oil respectively whereas SFE is found economically feasible and profitable extraction process.