Characterization of Linum usitatissimum L. oil obtained from different extraction technique and in vitro antioxidant potential of supercritical fluid extract

摘要

Aim: Present investigation was aimed to characterize the fixed oil of Linum usitatissimum L. using five different extraction methods: Supercritical fluid extraction (SFE), ultrasound-assistance, soxhlet extraction, solvent extraction, and three phase partitioning method. Materials and Methods: The SFE conditions (temperature, pressure, and volume of CO₂) were optimized prior for better yield. The extracted oils were analyzed and compared for their physiochemical parameters, high performance thin layer chromatography (HPTLC), gas chromatography-mass spectrometry (GC-MS), and Fourier-transformed infrared spectroscopy (FT-IR) fingerprinting. Antioxidant activity was also determined using 1,1-diphenyl-2-picrylhydrazyl and superoxide scavenging method. Result: The main fatty acids were α-linolenic acid, linoleic acid, palmitic acid, and stearic acid as obtained by GC-MS. HPTLC analysis revealed the presence of similar major components in chromatograms. Similarly, the pattern of peaks, as obtained in FT-IR and GC-MS spectra of same oils by different extraction methods, were superimposable. Conclusion: Analysis reported that the fixed oil of L. usitatissimum L. is a good source of n-3 fatty acid with the significant antioxidant activity of oil obtained from SFE extraction method. KEY WORDS: Fixed oil, Fourier-transformed infrared, gas chromatography-mass spectrometry, high performance thin layer chromatography, and supercritical fluid extraction Nowadays, the interest in the use of flaxseed ( Linum usitatissimum L.) has been increasing in order to improve the health status. The flaxseed contains fiber, lignans, proteins, and fixed oil, etc. The fixed oil of flaxseed is a good source of n-3 fatty acid. The beneficial effect of n-3 essential fatty acid on human health is well recognized.[ 1 , 2 ] The fixed oil of flaxseed also contains a significant amount of n-6 fatty acid that is also one of the essential fatty acids. The determination of the total oil content in the seeds is of paramount importance in the oil industry as the price of the raw material is a function of its richness in the final, commercial product. Traditionally, soxhlet extraction (SOXH), and solvent extraction (SOL) methods are used for the extraction of fixed oil. These methods mostly use hexane as an extracting solvent in a very large quantity, but hexane is a hazardous chemical. Furthermore, these conventional methods are very time-consuming and less efficient. Thus, there is a need for efficient methods to be made available for extracting the fixed oils. Over the last few years, there has been an increased interest in the development of solid, liquid extraction technique such as ultrasound-assisted (US) extraction, microwave assisted extraction, and supercritical fluid extraction (SFE). These techniques have the possibility of working at elevated pressure and/or temperatures and greatly decreasing the time of extraction, hydrolysis, and oxidation. Due to the environmental concerns and potential health hazards of organic solvents, nonorganic solvents have become popular. SFE technique mostly uses supercritical CO₂. The supercritical fluid has characteristics of both gases and liquids. In this study, we characterize the fixed oil of flaxseeds extracted by SFE and other conventional methods. We also studied the antioxidant potential of the extracted fixed oil of flaxseeds.