Evaluation of the effects of amphiphilic compounds on oxygen solubility in bulk oil

Abstract

SummarySolubility or content of oxygen molecules in oil matrices could be a critical factor to determine oxidative stability in lipid‐rich products. In this study, a method to determine oxygen content in oil was developed by gas chromatograph with a thermal conductivity detector (GC‐TCD), and factors affecting oxygen solubility or oxygen content were evaluated in bulk oil. Validation parameters were confirmed for headspace oxygen molecules using a GC‐TCD. Oxygen gas was spiked into headspace of air‐tight 10‐mL vials with 70% sample content produced more reliable results on oxygen molecules for 6 h duration. The ratio of 7:3 (w/w) between sample content and headspace was selected considering precision and sensitivity. Addition of lecithin significantly decreased oxygen solubility in bulk oil, while monoacylglycerols did not show such decreasing effects. Medium chain triacylglycerols (MCT) had significantly high oxygen solubility compared to conventional edible oils partly due to the relatively low surface tension. Heavily oxidised bulk oils had higher surface tension and lower oxygen solubility. Therefore, oils with relatively low surface tension had higher oxygen solubility. The results of this study can help to explain the oxidative stability of edible oils containing high amphiphilic compounds.