Influence of Polydimethylsiloxane on the Oxygen Concentration of Oils at Various Temperatures

• Published in: Journal of the American Oil Chemists' Society 2011-07, Vol.88 (7), p.925-929
• Main Authors: Gerde, Jose A., Hammond, Earl G., White, Pamela J.
• Format: Article
• Language: English
• Subjects: Agriculture; Biological and medical sciences; Biomaterials; Biotechnology; Catalytic oxidation; Chemical reactions; Chemistry; Chemistry and Materials Science; Emissivity; Fat industries; Food industries; Food Science; Fundamental and applied biological sciences. Psychology; Industrial Chemistry/Chemical Engineering; Oil surface temperature; Olive oil; Original Paper; Oxygen; Oxygen concentration; Oxygen consumption; Oxygen uptake; Polydimethylsiloxane; Soybean oil; Soybeans; Surface temperature; Temperature effects; Vegetable oils
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-011-1762-7

The effect of temperature on the oil oxygen concentration, tested in both soybean and olive oils with no added polydimethylsiloxane (PDMS), showed that the oxygen concentration increased with temperature to approximately 100 °C. Above 100 °C, the oxygen concentration abruptly decreased. This change was attributed to the balance between the rates of oxygen uptake and consumption by oil oxidation, which favored oxygen consumption over uptake at temperatures above 100 °C. The addition of 100 ppb PDMS to soybean oil, enough to form a continuous layer over the surface of the oil, reduced the oxygen concentration when compared to a soybean oil control containing no added PDMS at temperatures ranging from 93 to 180 °C; thus suggesting an oxygen barrier effect of PDMS. The accumulation of PDMS at the air–oil interface in soybean oil held at 180 °C was determined by comparing the oil’s internal temperature and the apparent surface temperature. A decrease in the apparent surface temperature while the oil was held at a constant internal temperature was attributed to a change in the emissivity of the surface as a consequence of the accumulation of PDMS in the air–oil interface. The presence of PDMS at the air–oil interface was confirmed for 100 ppm of PDMS, a concentration greater than the concentration necessary to form a monolayer of PDMS on the oil surface.