Optimization of the -3 extraction as a functional food from flaxseed

The fatty acid content, total lipid, refractive index, peroxide, iodine, acid and saponification values of Iranian linseed oil (Linum usitatissimum) were studied. For optimization of extraction conditions, this oil was extracted by solvents (petroleum benzene and methanol-water-petroleum benzene) in 1:2, 1:3 and 1:4 ratios at 2, 5 and 8 h. Then its fatty acid content, omega-3 content and extraction yield were determined. According to the statistical analysis, petroleum benzene in a ratio of 1:3 at 5 h was chosen for the higher fatty acid, extraction yield, and economical feasibility. For preservation of n-3 ingredients, oil with specified characters containing 46.8% n-3was kept under a nitrogen atmosphere at -30 degrees C during 0,7, 30,60 and 90 days and its peroxide value was determined. Statistical analysis showed a significant difference in the average amount of peroxide value only on the first 7 days of storage, and its increase (8.30%) conformed to the international standard. (Authors abstract)

Solvent extraction of oilseed is normally carried out with a solvent system (such as hexane) since it is the most efficient technique for oil recovery and the oil produced is of high quality. The extraction condition and changes of solvent have significant effects on physico-chemical characteristics of extracted oils. These changes were influenced by the degree of polarity of the primary extracting solvent. The objective of this study was to investigate the effect of different extraction conditions on the extraction yield and on the amount of n-3 fatty acid in Iranian flaxseed oil. ALA was the major fatty acid, followed by oleic acid, linoleic acid, palmitic acid and stearic acid. Different amounts of polar lipids were extracted with petroleum benzene and methanol-water-petroleum benzene. The major fatty acids of the polar lipid fractions were stearic acid (18:0), oleic acid (18:1) linoleic acid (18:2) and linolenic acid (18:3). These four fatty acids represented 84-92% of the total fatty acids in the polar lipid fraction although their relative amounts varied depending on the solvent system used for lipid extraction.  Statistical analysis showed a significant difference (PB5%) in the average amount of peroxide value only in the first 7 days of storage, and its increase (8.30%) conformed to the international standard (Codex 1999). (Editors comments)