Effects of Deuterium Oxide on the Oxidative Stability and Change of Headspace Volatiles of Corn Oil

Abstract

Effects of deuterium oxide and deuterium oxide-free water on the oxidative stability and formation of headspace volatiles were determined for corn oils to evaluate the role of moisture as an active influential factors during lipid oxidation. Mixtures of corn oil and water with different ratios of deuterium oxide were prepared, and the mixtures were stored at 60°C for 2 days. Headspace oxygen contents, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV) were analyzed as a measure of oxidative stability, and headspace volatiles were analyzed by solid phase microextraction and a gas chromatography mass selective detector to determine the involvement of deuterium in volatiles. Deuterium oxide accelerated the rate of lipid oxidation in corn oil compared to oils with deuterium-free water based on the results of headspace oxygen content, CDA, p-AV, and total volatile content. Fragmented mass to charge ratios (m/z) of 73.1/ 72.1 for d 1 -pentane/pentane and 57.0/56.0 for d 1 -2-propenal/2-propenal from samples containing deuterium oxide were significantly higher than those from deuterium oxidefree water, implying that moisture participated to form volatiles in corn oil oxidation under air-tight condition. Deuterium oxide appeared to accelerate the rate of lipid oxidation in corn oils and participated to form volatiles from oils during oxidation.

Effect of relative humidity and light conditions on the oxidative stability of sunflower oil blends stabilised with synthetic and natural antioxidants

“…In addition, moisture was shown to actively participate in lipid oxidation at higher temperatures. Kim et al (2014) reported the increased rate of formation of volatile compounds as a function of moisture content during oxidation of linoleic acid and corn oil in air-tight condition. The antioxidant capacity of antioxidants in bulk oils depends on its concentration and available moisture content.…”

Oxidative Stability and Volatile Formations in Linoleic Acid‐D2O Models in the Presence of Deuteron or Electron Donors

“…Although addition of acetic acidd accelerated the consumption of oxygen molecules based on Fig. 1a, some volatiles may be co-eluted with the large peak of acetic acid-d and results of total peak areas might not show prooxidative properties of acetic acid-d. Usually, presence of D 2 O significantly accelerated the consumption of headspace oxygen and generate more volatiles in samples compared to deuterium free H 2 O [11,12]. However, prooxidative properties of D 2 O were not observed in current experimental conditions.…”

“…The presence of D· in volatiles was analyzed by comparing m/z (mass to charge ratio) of each volatile [11,12]. A peak representing molecular weight may not be the most abundant peak.…”

“…Headspace volatiles like pentane had more deuterium (D·) in linoleic acid with D 2 O than those in deuterium free water (H 2 O), which implies that moisture can participate in the formation of volatiles during lipid oxidation [11]. This phenomenon can be observed in linoleic acid-water model systems without air-tightness or different treatment temperature condition [12].…”

“…Recently, the possibility of moisture as a substrate during the lipid oxidation has been reported by using analytical techniques for headspace volatiles in linoleic acid-deuterium oxide (D 2 O) model system [11,12]. Headspace volatiles like pentane had more deuterium (D·) in linoleic acid with D 2 O than those in deuterium free water (H 2 O), which implies that moisture can participate in the formation of volatiles during lipid oxidation [11].…”