Journal of the American Oil Chemists' Society

, Volume 77, Issue 3, pp 281–283 | Cite as

Factors affecting the electrical resistivity of soybean oil methyl ester

  • Aziz Tekin
  • Earl G. HammondEmail author


Factors affecting the electrical resistivity of soybean oil methyl ester (which is important in some industrial applications) were investigated by the addition of polar constituents [free fatty acids (FFA), water, phospholipids, monoglyceride, sterol, tocopherol, peroxides, and β-carotene] to aluminapurified soybean oil methyl ester (APSBOMe). Investigation of measuring conditions showed that reproducible results were obtained when the potential was greater than 25 V, and the charging time was greater than 10 s. The resistivity of APSBOMe increased logarithmically as temperature decreased linearly. FFA had little effect on resistivity. Saturation with water lowered the resistivity of APSBOMe much more than that of alumina-purified soybean oil (APSBO). Phospholipids reduced the resistivity significantly when added to dry ester, but the addition of water affected the resistivity of the samples containing phospholipids only slightly. Monoglyceride, sterol, tocopherol, and hydroperoxide affected the resistivity of dry methyl ester similarly, but only monoglyceride showed a significant synergistic effect with water. Diacylperoxide and β-carotene had little effect on the resistivity of the ester.

Key Words

β-Carotene charging time electrical resistivity free fatty acids oxidation products polar components soybean oil methyl ester temperature voltage 


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Copyright information

© AOCS Press 2000

Authors and Affiliations

  1. 1.Center for Crops Utilization ResearchIowa State UniversityAmes
  2. 2.Department of Food Science and Human NutritionIowa State UniversityAmes

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