γ-Tocopherol and sesamol: The chief contributors to color reversion in sesame oil.

Color reversion in sesame oil, which leads to inconsistent product appearance, poses significant marketing challenges. This study investigated this phenomenon and its contributing factors. A critical point of roasting for significant color reversion was identified at 200 °C for 30 min. Analytical results indicated that phospholipids are unlikely to be a dominant factor due to their low concentration. Correlation analysis and re-addition experiments confirmed γ-tocopherol as a precursor, with its oxidation products, such as tocored and dimers, implicated in the color change. Further re-addition experiments demonstrated that sesamin (2000-4000 mg/kg) does not contribute substantially to this process. However, sesamol (20-100 mg/kg) was identified as a key precursor, likely through the formation of colored dimers. These findings clarify the primary compounds driving color reversion in sesame oil and offer practical guidance for optimizing its processing.