Previous posts dealt with lauric, myristic, palmitic, stearic and ricinoleic acids. If you missed them, just click on the links to catch up.
Oleic acid is truly a soapmaker’s friend. What is so wonderful about oleic? In a nutshell, it contributes to a moisturizing and conditioning bar, yet is slow to trace and it offers a long shelf life. Oleic is no help however, with lathering and although it makes a hard bar, it does not make a long-lasting bar as soaps with palmitic and stearic acid do.
Without doubt, a soap formula is not complete without a good percentage of oleic acid, except for a few instances, as evidenced by the long history of olive oil in the most prized soaps in history.
The list of oils high in oleic acid is long and includes the ubiquitous olive oil, as well as high oleic sunflower and safflower oils. In addition, canola, sweet almond, apricot and peach kernel and avocado, of the often preferred oils are quite high in oleic. Of the less commonly employed, such wonders as carrot seed, pataua, camellia, papaya, marula, hazelnut, moringa, buriti, bear tallow, plum kernel, pistachio, macadamia nut, karanja and more fit the bill, and all boast more than 50% oleic fatty acid.
How long the shelf life or rancidity potential of any high oleic oil depends of course, on just how high the percentage of oleic is, as well as the other fatty acids that make up the oil, so carefully examine oils of interest and determine the best percentage for your formula based on that.
As an example, high oleic sunflower oil is about 83% oleic, so its shelf life is long enough that limiting the percentage due to fears of rancidity or DOS is unnecessary; whereas, canola oil at 61% and over 20% linoleic fatty acid, gives greater concern and should be used in a lower percentage. A high percentage of superfat incidentally, may affect the DOD and rancidity factor and should be taken into account, as well.
Join us for our next fatty acid review, linoleic acid.
Until next time, may your days be filled with bubbles and wax.
Beth Byrne, for Making Soap, Cosmetics & Candles Magazine
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