Struggling with crystalization and oxidation issues when formulating cosmetics? It’s all down to choosing the right shea butter.
With its natural, skin-nourishing benefits and sustainability credentials, shea butter is a highly-valued ingredient in cosmetics – and is the most frequently used plant-based butter in the industry.
However, when it comes to formulating, shea butter can be challenging to work with, particularly in higher concentrations or anhydrous systems. Suboptimal crystallization can result in crystal growth, which creates bloom and leads to a grainy, gritty texture. Oxidative instability can produce rancid odor, changing color, and alter the consistency of the final formulation.
Working with a high-quality shea butter can help mitigate these issues. Not all shea butter variants are the same, and quality can vary significantly depending on the sourcing and processing, which affect consistency and shelf life.
Want to know more on shea butter function in cosmetics? Watch our webinar!
Our Customer Innovation Manager, Benjamin Schwartz, and Global Commercial Product Manager, Elena Genescà Pont, recently delved deep into shea butter formulation challenges in a webinar – which you can watch here.
In just an hour, they explain:
- The reasons why cosmetic shea butter can be hard to work with
- What you should be aware of when selecting your ingredient, including the different grades of butter
- What you should focus on when making your evaluation and upscaling your formulations.
Key webinar takeaways: What formulators need to consider when choosing shea butter
Crystallization behavior and oxidation resistance parameters
To avoid bloom, crystal growth behavior must be controlled. As crystals grow due to the speed of transition to its stable crystal forms, look for shea butter with a fast transition to the stable crystal form.
If you’ve experienced a cosmetic product changing color, developing a rancid odor, changing texture or irritating the skin, oxidation could be the root cause. This is common when working with natural ingredients like shea butter, and cause product breakdown.
Shea butter is composed mainly of triglycerides, but rich in unsaponifiables. Resistance to oxidation depends on the quality, i.e. the amount of free fatty acids, contaminants and processing. The content of polyunsaturated fatty acids (PUFAs) is a good indicator of its oxidative stability, as these are more easily oxidized. Light, heat and presence of oxygen can also impact on oxidative stability.
When assessing shea butters and their resistance against oxidation, look at Oxidative Stability Index (OSI) and Peroxide Value (PV) - the parameters used to evaluate degree of oxidation and oxidative stability.
How our LIPEX® Shea provides the solution for cosmetic formulators
AAK’s LIPEX® Shea transitions four times faster to stable crystal form than standard refined shea butter, resulting in smaller crystals being formed during the crystallization process – therefore significantly reducing the risk of bloom.
We put it to the test against standard refined shea butter through cooling and heating cycles, which you can view on our YouTube channel.
LIPEX® Shea has more than double the resistance to oxidation compared to standard refined shea butter, too, thanks to specialized AAK processing. It has high OSI and slower PV development, resulting in a longer shelf life.
