Abstract:

The changes in physico-chemical properties, fatty acid composition and vitamin E content of solvent extractionderived flaxseed oil during the refining process consisting of degumming, alkaline treatment and bleaching, deodorization were measured in order to address the effect of refining on the physico-chemical properties and nutritional composition of solvent extraction-derived flaxseed oil. Over the whole refining process, the content of phospholipids and acid value markedly decreased, from 1.541 to 0.163 g/100 g and from 2.826 to 0.635 mg KOH/g, respectively. However, no obvious change in iodine value, saponification value and refraction index was observed. The capillary column gas chromatographic analysis revealed that solvent extraction-derived flaxseed oil contained 4 saturated fatty acids (mainly hexadecanoic acid and stearic acid) and 6 unsaturated fatty acids (mainly linolenic acid, linoleic acid and oleic acid). Refining had little effect on the fatty acid composition and total fatty acid content in solvent extraction-derived flaxseed oil, but the relative content of linolenic acid presented an obvious decrease, especially at the stages of bleaching and deodorization. The refining process gave a vitamin E loss of up to 49.19%, indicating that the nutritional composition of solvent extraction-derived flaxseed oil was greatly affected by the refining process.

Key words: solvent extraction flaxseed oil, refining, physico-chemical properties, nutritional components