SUMMER 2017 • Vol. 23 No. 6
New York Society of Cosmetic Chemists
www.nyscc.org
Oleosomes: Nature’s Delivery System
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James V. Gruber, Ph.D.
leosomes are triglyceride oils (unique for each plant seed) surrounded by a phospholipid shell that is then enshrouded in a monolayer sphere of oleosin proteins. An in-depth discussion of the structure of the oil seed oleosome can be found in a review article by Jason Tzen.1 Nature creates the oleosome capsules to maintain the oil in the seeds until required for germination and growth of the plant. Nature also places a protein store house in each seed, called storage proteins, that provide a nitrogen source for the small plant. Oils from various plants are very popular for topical treatments as they help improve skin barrier function, hydration, and conditioning. Oilseed oil extractions typically are run through extruders that crush the seeds under high pressure and high temperatures. Crushing ruptures the oilseed oleosomes to release their oil. Crushing extraction creates a seed cake which still typically contains about 25-30% of the available oil. Usually, the seed cake is further extracted using hexane, a toxic organic solvent. During crushing extraction, the storage proteins are effectively denatured and trapped into the hulls (called meal). The value of the crushed proteins is essentially lost in the extraction process and these valuable components become simple animal feed.
Sustainable Extraction of Oilseed Oleosomes and Proteins If a consumer were to buy oil as found in nature, it would not appear as the clear liquid commonly found on the shelf, but rather would look very much like a creamy emulsion, similar to mayonnaise (see Figure 1). Great efforts have been made in industry to develop sustainable techniques to extract plant oil seed oleosomes.2 The safflower seed is a highly sustainable seed that grows without genetic modification in low water environments. It is an ideal seed for development of highly sustainable oleosomes. It should be noted that other unique seeds like sunflower, almond, hemp, and canola also contain oleosomes and can be extracted using the process described in this article. The process of oleosome extraction begins with the oil seeds. The seeds are washed with water and then passed through a series of gentle grinding steps to create an aqueous seed extract. Temperatures never exceed 60 °C and no toxic organic solvents are employed in the extraction process. Through a series of further decanting and centrifugation steps, highly refined oleosomes, containing less than 2% of residual seed proteins can be made. Such an extraction process creates three plant streams: the oil fraction containing the cleaned and stabilized oleosomes, an aqueous phase, and a small residual solid phase that contains primarily the cellulosic and hemicellulosic materials from the hulls. The aqueous (Continued on page 4)
# B e y o n d T h e B r i e f S e p t e m b e r 6 t h • P e c l e r s P a r i s H Q , N e w Yo r k , N Y