Effects of steeping conditions during wet‐milling on the retentions of tocopherols and tocotrienols in corn

Abstract

Abstract Vitamin E is a natural antioxidant that plays significant roles in food preservation and disease prevention. There are eight naturally occurring vitamin E isomers (tocols): α‐, β‐, γ‐, and δ‐tocopherols and α‐, β‐, γ‐, and δ‐tocotrienols. Corn oil is a major source of vitamin E. Most of the corn oil produced in the United States is a co‐product of corn wet‐milling. There is limited knowledge about the effects of corn wet‐milling on the retention of these vitamin E isomers. A high‐performance liquid chromatography method was developed for simultaneous determinations of tocols in steeped corn samples. Effects of steeping conditions (steeping time and SO 2 concentration) on retention of tocols in corn were investigated. α‐Tocopherol, γ‐tocopherol, α‐tocotrienol, and γ‐tocotrienol are the predominant vitamin E isomers in the corn variety used in the study. Steeping conditions had little effect on the concentration of α‐tocopherol and α‐tocotrienol. However, a higher concentration of SO 2 and a shorter steeping time gave a slightly higher γ‐tocotrienol content and lower γ‐tocopherol content. Corn kernels steeped in a vitamin C solution had a much higher concentration of the tocols than those steeped in SO 2 solution.