Multistage microwave assisted solvent extraction of soil from turmeric

• Main Author: Lim, Pisey
• Format: text
• Language: English
• Published: Animo Repository 2013
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4590
• Institution: De La Salle University

Microwave-Assisted Solvent Extraction (MASE) is an effective extraction technology, which uses microwave energy to remove the desired compounds from raw material by using solvent. MASE causes a significant increase in the extraction efficiency and a reduction in extraction time and solvent consumption at low extraction temperature, thus, destruction of the thermal sensitive components in oil can be minimized. Turmeric oil possesses excellent anti-inflammatory activity and skin-soothing properties. The major components in turmeric oil are the turmerones which have powerful antioxidant activities. Turmerones are commonly used as one of the ingredients in skin care products for reducing the appearance of wrinkles and the like. This study focused on the extraction yield of turmeric (Curcuma longa) oil using Multistage Microwave-Assisted Extraction by applying the optimized values of parameters in a single-stage MAE. For the single-stage Microwave-Assisted Extraction, the following parameters were varied: extraction time (1, 3.5 and 6 minutes), extraction temperature (50, 60 and 70oC), and sample-solvent ratio, w/v (1:3, 1:4.5 ad 1:6). The obtained data were analyzed by CCD using Response Surface Methodology with Design Expert Software 7.1.5. This research work demonstrated that the optimum conditions for single-stage MAE attained 14.41% of turmeric oil at 50oC, 6 minutes, and 3:1 (ml/g) of ethanol/turmeric powder however, at the same conditions of temperature, time of operation, and ethanol/turmeric powder ratio, three-stage MAE resulted in 13.98% yield and two-stage MAE 13.62%. By using 6:1 (solvent/sample ratio, v/w), 50oC and 6min 3-stage MAE resulted in 14.45% of turmeric oil and single-stage MAE yielded 13.29%. The chemical compositions of the turmeric oleoresins were determined by GC-MS analysis. At the optimum conditions of single-stage and multistage MAE operations, the aromatic turmerone and a (or b)-turmerone were identified as compounds present in the turmeric oleoresins. The physico-chemical properties were determined and considered as indicators of quality value of the turmeric extracts. The refractive index of the extracts obtained from multistage MAE (RI: 1.574) gave greater values than that from single-stage MAE (RI: 1.561). However, these two values were deviated from range cited in the standard turmeric oil. This may be so because the extract from MASE is an oleoresin and not pure oil. The specific gravity of turmeric oils from MASE and MMAE ranged from 1.007 to 1.0530 which was higher than the normal range. Furthermore, it was noted that the specific gravity of the extract produced by MAE with solvent was significantly higher than that of the standard oil. This was attributed to the presence of the curcuminoids in the extract with other heavy molecular-weight compounds. The acid values of turmeric oil produced by both techniques, single-stage (AV: 2.233) and multistage-MAE (AV: 2.149), were comparable to the acid value from the standard oil which was 2.092. However, the ester value of the oil produced by MAE with solvent cannot be determined due to the unknown amount of oil present in the turmeric oleoresin and the appearance of the dark color which gave incorrect value for the volume of HCL.