here is some info from Snowdrift Farms website about ROE, GSE and Vit E:
What's the difference between Vitamin E, grapefruit seed extract (GSE) and rosemary extract or oleoresin? Are they all preservatives?
There are significant differences between GSE, Vit. E and Rosemary Extract (ROE).
The differences between Vit. E and ROE occur in two major areas. Since oxidation leading to rancidity occurs only on the hydrophobic (oil soluble) portion of the molecule, the antioxidant must be in the physical area of the oil molecule's double bonds to be effective. The reaction must be prevented at these sites. A water soluble antioxidant will not be physically mobile enough in the oil domain of the molecule to participate in the reaction. Therefore, oxidation will proceed unimpeded. However, oil soluble antioxidants will be physically present in the right locations.
The principal active ingredients in GSE are water soluble bioflavanoids. These compounds do have antioxidant properties, BUT these compounds are not available to the oil of the soap molecule, where they are needed. Instead, they reside in the residual water or near the hydrophillic (saponified) end.
A similar situation occurs with Vitamin E. Vit. 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. Both appear to be as effective as butylated hydroxytoluene (BHT). GSE was not tested.
How much antioxidant should I use?
Antioxidants are usually effective at levels of about 200 mg to 1000 mg per kg of product. This translates roughly to .2-1 gram per kilogram. (Trina's note: a standard teaspoon measure should be more than sufficient per 10 pounds of oils.) Antioxidants may be used together. The mobile compounds in ROE may act as a transfer agent, increasing its effectiveness when used in tandem with water soluble antioxidants.
How are antioxidants made?
GSE is made from the dried, ground seeds and pulp of the grapefruit. The pectin and fiber are removed using distilled water and the mixture is spray dried. This concentrate is dissolved in glycerin. Ammonium chloride and citric acid are added to break the glucosides down and release the bioflavinoids. The mixture is then heated under pressure to complete the reaction. The bioflavinoids are converted to water soluble quaternary compounds during this reaction. Vitamin E is available from a wide variety of sources, both natural and synthetic. It has strict USP and FCC standards. Most GSE available on the market today contains significant amounts of active preservatives, such as triclosan. It is not the GSE that is working, rather the active preservative. There are no studies that conclude that GSE is an effective anti-bacterial or preservative.
Rosemary extract or oleoresin (ROE) is prepared by extraction and the removal of the extractant. The standards for ROE are listed in the FCC (food chemical codex) Snowdrift Farm's ROE has a faintly herbal odor. It is FCC antioxidant grade with no volatile oils
Here is the direct link:
http://www.snowdriftfarm.com/askthechemist.html
