Physical and chemical characterizations of normal and high-oleic oils from nine commercial cultivars of peanut

Density and viscosity data as a function of temperature (5-100 degrees C) were collected for oils (normal and high-oleic) from nine cultivars of peanut. Density decreased linearly (R-2 >= 0.99) with increasing temperature for all oils, whereas viscosity (dynamic or kinematic) decreased exponentially with increasing temperature. At any particular temperature, dynamic viscosity increased linearly (R-2 >= 0.95) with decreasing oil density among the various oils. Slopes of the linear fits (with units of kinematic viscosity) for dynamic viscosity versus density plots decreased in an exponential fashion as the measurement temperature decreased. High-oleic oils had both the lowest densities and highest viscosities, with viscosity differences being most apparent at cooler temperatures. Increasing contents of oleic acid, decreasing contents of linoleic acid, and decreasing contents of palmitic acid were each associated with decreased density and increased viscosity among the oils. Two of the three high-oleic oils had the significantly (p < 0.05) highest content of total tocopherols, while the other high-oleic oil was statistically grouped with the oils having the 2nd highest total tocopherol content. This suggests a link between increased total tocopherols and high-oleic peanut oils; however, no obvious linear correlations were observed in tocopherol content and oil physical properties (density or viscosity).