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The Value of Green Processing
By: Stephanie K. Clendennen, PhD and Neil W. Boaz, PhD
Posted: October 9, 2008, from the October 2008 issue of GCI Magazine.
With growing and widespread consumer interest, natural ingredients have become an important consideration for cosmetics. And as consumers delve deeper into the ingredient list in a quest to fulfill their desire for “natural” to the furthest extent possible, the demand for the use of green processes will also grow—thus becoming of direct importance to formulators. Consideration of and investment in increasingly green processes, therefore, can be a boon to brand equity.
Though it is difficult to find a single standard, natural typically refers to the source of the raw materials, while “green” refers to the process used to convert starting materials to a finished ingredient. While there are useful guidelines for designing greener processes for ingredients, there is a shared burden—by suppliers, formulators and marketers—to communicate the green story to consumers. Third-party certification is one way of communicating this message and ensuring the benefits of the process itself are also realized in brand equity.
Yes, Processes Can Be Green
While not absolutely necessary, perhaps, green processing is relevant in the manufacture of naturally derived cosmetic ingredients. Natural materials are usually derived from plants or microbes via fermentation with minimal processing. Cold-pressed seed oils are excellent examples. The derived oils can be converted to glycerol and fatty acids, which are both good starting materials for making cosmetic esters. Esters encompass actives, emollients, emulsifiers and surfactants—and antiaging ingredients such as retinyl palmitate are esters.
Traditionally, esters are made synthetically in the presence of a strong acid catalyst and elevated temperatures to both drive the reaction and remove the water by-product. Acid-catalyzed, high-temperature esterification reactions are both energy intensive and the reaction conditions are deleterious to many starting materials, such as unsaturated fatty acids. Under harsh conditions, these sensitive starting materials produce undesirable color, odor and by-products that impact yield. In addition, additional process steps must be included to remove the strong acid catalyst.
In contrast, a major benefit of biocatalytic processes are mild reaction conditions that often avoid degradation of sensitive products and result in improved color, odor and by-products. There have been plenty of reports of biocatalytically prepared cosmetic esters, but many have required the use of organic solvents for both the reaction and for post-reaction processing to purify the final product. A real breakthrough in the deeper “greening” of biocatalytic processes is the elimination of the organic solvent in the reaction performed in the absence of added organic solvent, which makes a significant environmental impact.