E is usually supplied as the oil soluble tocopherol acetate. During saponification, the acetate group is removed by the same reaction which makes soap from triglycerides. The tocopherol is now water soluble and not available where it is needed. Vitamin E acetate may be used as an effective preservative in non-saponified products. It is not as stable as the compounds in Rosemary oleoresin.
Rosemary oleoresin is oil soluble.
The antioxidants in it do not react with sodium hydroxide. They retain their antioxidant qualities and are available in the oil molecules where they are needed. The effectiveness of ROE and Vitamin E acetate were measured using a Rancimet assay in various oils. They appear to have similar initial activity, although the results can not be directly compared due to the use of different concentrations. GSE was not tested.