Evaluation of Oxygen-Limitation on Lipid Oxidation and Moisture Content in Corn Oil at Elevated Temperature
2014
Park, Jung Woo | Kim, Ji-Young | Kim, Mi Ja | Lee, JaeHwan
The role of oxygen-limitation on lipid oxidation and moisture content were tested in corn oil heated to 60, 100, and 140 °C. The degree of oxidation was determined by analyzing headspace oxygen content, conjugated dienoic acids (CDA), and p-anisidine value (p-AV). The moisture content in bulk oil was analyzed by the Karl Fischer method. Oxygen-limited samples heated to 100 and 140 °C had significantly more lipid oxidation than oxygen-unlimited samples at early timepoints (p < 0.05). After this period, the oxygen-unlimited samples had more lipid oxidation based on CDA and p-AV assays. During those initial periods, oxygen-limited samples had significantly higher moisture content than oxygen-unlimited samples (p < 0.05), which implies that moisture content in oils plays an important role in the rate of lipid oxidation. The increased moisture content in bulk oil under oxygen-limited conditions is due to headspace moisture rather than moisture inside the oil. However, the effects of oxygen-limitation on lipid oxidation were less clear at 60 °C than at 100 or 140 °C.
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