Help with soap formula

[topofmurrayhill]

But isn't superfat contributing to making DOS more visible/intense? I guess that an old oil (and/or bad curing conditions) will make less amount of DOS in a soap with 1% superfat compared to a soap with >5% superfat.

:think:

Fatty acids oxidize whether they are in triglycerides or sodium salts. When Kevin Dunn tested ways of preventing DOS, the induction period for discoloration of soap with 10% lye discount and soap with 0% lye discount was the same. That indicates that a high discount does not increase the chances of DOS. The high discount soap did turn more orange, but that's insignificant when you consider how much you can lengthen the induction period with chelators and antioxidants. If you don't use stabilizers, natural or synthetic, avoiding metal ions in your soap and avoiding unsaturated (especially polyunsaturated) fatty acids is much, much, MUCH more significant that the amount of unsaponified oil in your soap.

 

[ngian]

In any case, Rosemary Oleoresin Extract is a natural additive that will increase the shelf life of your soaps significantly. It would be good practice to use distilled water and add ROE to your oils.

Is this ROE actually around 90% Rapeseed Oil and 10% Extract? This is what two soap supply stores told me through the MSDS files of the product, and I'm asking here to be sure that this is the antioxidant ROE. The second store could also tell me that its ROE has carsonic acid >4%

 

[shunt2011]

Is this ROE actually around 90% Rapeseed Oil and 10% Extract? This is what two soap supply stores told me through the MSDS files of the product, and I'm asking here to be sure that this is the antioxidant ROE. The second store could also tell me that its ROE has carsonic acid >4%

The companies I've checked state it's only the extract from rosemary leaves. No other additives. It should be thick and syrupy and a dark green/brown color.

Here's just one description but WSP has their Data Sheet on their site too.

Rosemary Oleoresin Extract (ROE) - Hexane Free

Rosemary Oleoresin, also known as Rosemary Oil Extract or ROE is an oil soluble, natural extract of the leaves of the rosemary plant used to retard rancidity in natural oils. Its potent antioxidant properties are attributed in large part to carnosic acid, one of its major constituents. Rosemary Oleoresin is available with varying levels of carnosic acid. Ours is highly concentrated and standardized to 7% carnosic acid for the highest level of activity, making its use at very low percentages both effective and economical. Typically, 0.2 - 0.5 grams will be added to 1000 grams of oil.
As with any antioxidant, to be effective Rosemary Oleoresin must be added to oils when they are fresh, before oxidation has started. Additionally, it must be thoroughly dispersed in the oil. As Rosemary Oleoresin is a thick liquid, adequate dispersion can be difficult. We recommend it be predispersed in a small portion of the oil first and this added to the balance of the oil with thorough mixing.
Rosemary Oleoresin (ROE) has a very mild herbaceous odor which is generally unnoticeable in final formulations when used at recommended usage levels. It is a high quality product lacking the pulp or graininess often found in lesser Rosemary Oleoresin products. In addition to Carnosic Acid, Rosemary Oleoresin also contains Rosmarinic Acid, Rosmaridiphenol, Carnosol, Rosmanol, and Rosmaridiquinone.
Recommended Use Level: 0.02% - 0.05%
Appearance: Light brown viscous liquid
Carnosic Acid Content: 7% minimum
Solvent used for Extraction: Acetone
Country of Origin: Canada
Flashpoint: >212°F (100°C)

INCI: Rosmarinus Officinalis (Rosemary) Leaf Extract

So, it shouldn't be mixed with anything else.

 

[topofmurrayhill]

Is this ROE actually around 90% Rapeseed Oil and 10% Extract? This is what two soap supply stores told me through the MSDS files of the product, and I'm asking here to be sure that this is the antioxidant ROE. The second store could also tell me that its ROE has carsonic acid >4%

Like shunt, I have seen no information to the effect that ROE is anything except extract from rosemary leaves.

Unfortunately, we are typically just told the carnosic acid content, but that is not the active ingredient. The antioxidant effect comes from rosmarinic acid.

 

[ngian]

Unfortunately, we are typically just told the carnosic acid content, but that is not the active ingredient. The antioxidant effect comes from rosmarinic acid.

Wikipedia says that both of the acids you mentioned have antioxidant properties. Do you have any other source that states the same thing with you?

 

[topofmurrayhill]

Wikipedia says that both of the acids you mentioned have antioxidant properties. Do you have any other source that states the same thing with you?

Yes. Kevin Dunn tested them separately and determined the effective compound. It's stated in his book Scientific Soapmaking. I also have a research paper that explores various ways of extending the shelf life of shea butter, and they simply used rosmarinic acid instead of the whole extract.

 

[ngian]

So after searching a bit, I think rosmarinic acid alone isn't easily to buy some, so we just have to get the ROE and use it instead without knowing the real amount of the specific acid.

 

[topofmurrayhill]

So after searching a bit, I think rosmarinic acid alone isn't easily to buy some, so we just have to get the ROE and use it instead without knowing the real amount of the specific acid.

That was my conclusion too. The prices I have seen for purified rosmarinic acid are prohibitive. However, the extract had been tested against synthetic antioxidants and is demonstrated to be very effective. A synergistic combination of antioxidant and chelator in Dunn's experiments was ROE with EDTA. For some reason, the combination with sodium citrate didn't work well.