Physico-Chemical Stability of Flaxseed Oil with Natural
Physico-Chemical Stability of Flaxseed Oil with Natural
Year: 2005
Authors: Jaswir, I. Kitts, D.D. Che Man, Y.B Hassan, T.H.
Publication Name: Journal of Oleo Science
Publication Details: Volume 54; Number 2; Pages 71 – 79.
Abstract:
An optimization study has been carried-out to evaluate synergistic effects of natural antioxidants on physico-chemical characteristics of flaxseed oil during heating. Results showed that the use of oleoresin rosemary extract, sage extract and citric acid improved the stability of the oil during 20 times of frying. This study also revealed that the addition of these antioxidants effectively retarded flaxseed oil deterioration after as early as 5 times of frying of potato chips. Analyses from Response Surface Methodology (RSM) indicated that for all physico-chemical characteristics of flaxseed oil evaluated, all mathematical models or equations could be developed with high confidence, where all R2 values greater than 0.87. From this study, the highest R2 (0.98) was shown by yellow colour, followed by absorbance at 268 nm (0.97), saturated /unsaturated fatty acid ratio (0.95), absorbance at 232 nm (0.93), and AnV (0.92). R2 values for four other parameters were 0.88 (PV and IV) and 0.87 (FFA and red colour). This meant that the R2 values obtained from this study were all satisfactory and considered accurate enough, not only for prediction purposes, but also for optimization purposes. (Authors abstract)
A number of physical and chemical changes involving a complex pattern of thermolytic and oxidative reactions occur in fats and oils during heating. In commercial heating procedure during the preparation of foods, fat is continuously exposed to air and light for extended periods at temperatures approaching 180℃. The lipid composition of food systems cooked by heating will potentially promote chemical changes within the oil used. It is well established that these reactions result in rapid deterioration of the heated oil that ultimately affects the functional, sensory and nutritive values, as well as the safety of foods processed. For these reasons, antioxidants are added to fats, oils and foods containing fats to inhibit the development of off-flavour arising from the oxidation of unsaturated fatty acids. Flaxseed is an unique oil because of its very high content of the polyunsaturated. It contains a big proportion of alpha-linoleic acid (ALA), now recognized as an essential fatty acid in the diet. Flaxseed oil normally contains 9% saturated fat, 18% monounsaturated fat, 16% linoleic acid and 57% ALA. However, the high content of unsaturated fatty acids in flaxseed can limit its shelf-life, because these fatty acids are very prone to oxidation. This study was conducted to investigate the effects of synergies between several natural antioxidants, namely oleoresin rosemary extract (OR), oleoresin sage extract (OS) and citric acid (CA) on changes in physico-chemical properties of heated flaxseed oil during the frying of potato chips. Response surface methodology (RSM) was used to quantitate the potential synergistic effects of the three antioxidants. The addition of these antioxidants effectively retarded flaxseed oil deterioration after as early as 5 times of frying of potato chips. The highest R2 (0.98) was shown by yellow colour, followed by absorbance at 268 nm (0.97), saturated /unsaturated fatty acid ratio (0.95), absorbance at 232 nm (0.93), and AnV (0.92). R2 values for four other parameters were 0.88 (PV and IV) and 0.87 (FFA and red colour). This meant that the R2 values obtained from this study were all satisfactory and considered accurate enough, not only for prediction purposes, but also for optimization purposes. (Editors comments)
A number of physical and chemical changes involving a complex pattern of thermolytic and oxidative reactions occur in fats and oils during heating. In commercial heating procedure during the preparation of foods, fat is continuously exposed to air and light for extended periods at temperatures approaching 180℃. The lipid composition of food systems cooked by heating will potentially promote chemical changes within the oil used. It is well established that these reactions result in rapid deterioration of the heated oil that ultimately affects the functional, sensory and nutritive values, as well as the safety of foods processed. For these reasons, antioxidants are added to fats, oils and foods containing fats to inhibit the development of off-flavour arising from the oxidation of unsaturated fatty acids. Flaxseed is an unique oil because of its very high content of the polyunsaturated. It contains a big proportion of alpha-linoleic acid (ALA), now recognized as an essential fatty acid in the diet. Flaxseed oil normally contains 9% saturated fat, 18% monounsaturated fat, 16% linoleic acid and 57% ALA. However, the high content of unsaturated fatty acids in flaxseed can limit its shelf-life, because these fatty acids are very prone to oxidation. This study was conducted to investigate the effects of synergies between several natural antioxidants, namely oleoresin rosemary extract (OR), oleoresin sage extract (OS) and citric acid (CA) on changes in physico-chemical properties of heated flaxseed oil during the frying of potato chips. Response surface methodology (RSM) was used to quantitate the potential synergistic effects of the three antioxidants. The addition of these antioxidants effectively retarded flaxseed oil deterioration after as early as 5 times of frying of potato chips. The highest R2 (0.98) was shown by yellow colour, followed by absorbance at 268 nm (0.97), saturated /unsaturated fatty acid ratio (0.95), absorbance at 232 nm (0.93), and AnV (0.92). R2 values for four other parameters were 0.88 (PV and IV) and 0.87 (FFA and red colour). This meant that the R2 values obtained from this study were all satisfactory and considered accurate enough, not only for prediction purposes, but also for optimization purposes. (Editors comments)
