Oxidative Stability in Bulk Oil Containing Carbohydrates Such as Glucose, Sucrose, Maltose, Mannitol, and Starch

Effects of carbohydrates including glucose, sucrose, maltose, mannitol, and starch on the oxidative stability of corn oils were evaluated at 40 A degrees C for 51 days, at 100 A degrees C for 17 h, and at 180 A degrees C for 90 min. The degree of oxidation was determined by headspace oxygen content, conjugated dienoic acid (CDA) assay, or p-anisidine value (p-AV) and the moisture content of the oils was analyzed. Starch showed pro-oxidant properties whereas mannitol acted as an antioxidant at all tested temperatures. However, glucose, sucrose, and maltose showed different properties depending on the temperature and type of assays. At 40 A degrees C, glucose, sucrose, and maltose showed antioxidant properties in headspace oxygen and CDA assays. There were no significant differences in CDA between samples at 100 and 180 A degrees C. p-AV in samples containing glucose were significantly higher than those in controls at 180 A degrees C, which may be due to the formation of volatiles from caramelization rather than lipid oxidation. Moisture content of oils containing glucose and starch was significantly higher than that of controls, whereas that of oils containing mannitol was lower than in the control (p < 0.05). Changes in moisture content of oils may be due to the migration of moisture from added carbohydrates into the oils.