Characterists of Flaxseed Oil from Two Different Flax Plants.
Characterists of Flaxseed Oil from Two Different Flax Plants.
Year: 2011
Authors: Zhang, Z-S. Wang, L-J Li, D. Li, S-J Ozkan, N.
Publication Name: Intern Food Prop.
Publication Details: Volume 14; Pages 1286-1296
Abstract:
Flaxseed oil is rich in linolenic acid, and being accepted in diet by more and more people.
The characteristics of flaxseed oil from two different varieties, namely fibre flax seed and oil flax seed, were evaluated. It was shown that fatty acids of flaxseed oil were mainly constituted by linolenic, oleic, linoleic, stearic, and palmitic acids, and the oil-flax seed oil contained more linolenic acid (58.03percent) compared with the fibre flax seed oil (47.37percent). The fibre-flax seed oil showed a higher absorbance at 290 to 800 nm. Thermogravimetric curves
showed that the oil-flax seed oil was more stable than the fibre-flax seed oil. Thermal profiles indicated that the fibre-flax seed oil had higher melting peak temperature and larger enthalpy. Rheological studies indicated that the apparent viscosity of the fibre-flax seed oil
was higher than that of the oil flax seed oil. It can be concluded that the oil-flax seed oil is better than the fibre flax seed oil in terms of edibility. (Authors abstract)
Flax (Linum usitatissimum L.) is an important oil plants in China, oil flax and fibre flax. The aims of this study were to compare physico chemical characteristics, fatty acid composition, spectroscopic properties, thermal properties, and rheological properties of the FFS oil with those of the OFS oil, and show the differences between these oils obtained from different sources. Compared with the FFS oil, the OFS oil was higher in unsaturated fatty acids content (90.70percent vs. 83.53percent) and ratio of n3/n6 (3.61 vs. 3.08). The FFS oil contained more yellow colouring than the OFS oil, as indicated by the absorbance at 440–460 nm for 10percent oil in hexane. This yellow colour, which includes carotenoids, is beneficial, since it stimulates the appearance of butter without the use of primary colourants, such as carotenes and annattos, and apocarotenals commonly used in the oil and fat industry. When the thermogravimetric curves of the FFS and OFS oils were compared, a mass increase in the temperature range 120–220◦C followed by a rapid mass loss was observed for the OFS oil. The mass increase may be attributed to lipid oxidation process, which absorbed oxygen to form peroxides. The apparent viscosities of flaxseed (OFS and FFS) oils as a function of shear rate ranging from about 15 to 800 s−1. The apparent viscosity of the FFS oil was larger than that of the OFS oil at the same temperature. This study indicated that magnitude of the apparent viscosity of flaxseed oils was greatly influenced by temperature. The lower acidity value and peroxide value of the OFS oil indicate that the OFS oil have a better quality and longer shelf life than the FFS oil. This result was conflicted with higher saturated fatty acids content of the FFS oil. Both total polyphenol content of the OFS and FFS oils were in the range of 76–307 mg/kg.It was
found that the OFS oil contained more unsaturated fatty acid content (USFA), especially the linolenic acid content of the OFS oil was higher than that of the FFS oil. Thermogravimetric curves showed that the higher USFA did not affect the stability of the OFS oil relative to the FFS oil. Higher absorbance of the FFS oil indicated that the FFS oil fit to be used in cosmetics as a formulation of UV protector. The apparent viscosity of the FFS oil was larger than that of the OFS oil. The FFS and OFS oils showed almost a Newtonian behavior at the shear rates between 15 and 800 s−1. Lower acid and peroxide values also indicated that the OFS oil was more suitable as edible oil than the FFS oil. (Editors comments)
