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Home , Shea butter

pp31-33 PCEuroSep09 5/11/09 14:25 Page 1

Jari Alander – AarhusKarlshamn Sweden AB (AAK) Shea with improved moisturisation properties

Shea butter has recently become a very popular ingredient in and personal care applications due to its good emolliency and moisturising properties. The high content of unsaponifiable lipids, especially triterpene cinnamates, contributes to skin healing and restoration by anti-inflammatory action. Shea butter in all its forms is also easy to formulate with, especially if one of the butters specifically developed for cosmetic applications is used. All in all, this indicates that shea butter is both a functional and marketable ingredient with a long history of safe use in cosmetics and explains well its popularity in modern skin care. With new developments such as Lipex Sheasoft from AAK, the formulation opportunities are better than ever.

Shea butter is available in many forms The shea tree, or karité tree, on the savannah in . Shea butter is obtained from the kernels of the shea tree (also known as the Triglycerides and triterpene esters about 100 ppm, corresponding to a low karité tree) which grows in the semi-arid – main constituents of shea butter level of sensitive polyunsaturated fatty savannah of sub-Saharan Africa. The shea Shea butter, in common with most other acids in the . The main shea butter fatty butter trade is a very important factor for vegetable and , are triglycerides acids, oleic and , are sufficiently the economy of the communities in this (esters of glycerol and fatty acids). stable against oxidation without the aid of area and has a long history as a source However, shea butter also contains very tocopherol. for edible fat and for skin treatments. high levels of non-glyceride components, The original shea butter is a yellowish normally summarised by the collective term Melting profiles determine paste with a characteristic odour and “unsaponifiables” or “unsaponifiable consistency and heat stability refining is normally required to produce matter”. A typical vegetable contains The physicochemical properties of an ingredient for cosmetic use. The shea less than 1% of unsaponifiables, mainly vegetable oils and fats are generally given butter can be further processed into a phytosterols and tocopherols. In contrast, by the composition of the variety of ingredients with improved shea butter can contain as much as 7% to constituent triglycerides. Longer fatty acid functionality and today a large range of 10% of unsaponifiable matter, comprising, chain lengths increase melting points while shea butters for cosmetic use is available. among other components, triterpene increased unsaturation give lower melting Properties such as the melting point and alcohols esterified to cinnamic acid, acetic substances. As all vegetable oils and melting profile, as well as the content of acid and long chain fatty acids. On the butters are composed of many different unsaponifiable matter, can be optimised other hand, the content of tocopherols in triglycerides, a single melting point can to meet requirements for different shea butter is comparatively low, often normally not be given. Instead the melting applications. Liquid shea butter is ideal for light Table 1: Composition of shea butters. formulations and for cold processing while Lipex Sheasoft Refined shea butter semi-solid butters are better suited for heavier formulations and for fine-tuning (%) 4-5 3-5 the consistency of the formulation. The Stearic acid (%) 41-43 41-45 selection of a shea butter ingredient in (%) 44-45 43-45 a formulation usually depends on the type (%) 6-8 5-7 of formulation, its desired sensory profile Tocopherols (ppm) <100 <100 and the positioning of the formula in the Unsaponifiable matter (%) 5-8 2-8 market.

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BUTTERS

profile, given as the percentage solid fat at each temperature, is used to characterise 50 45 semi-solid fats, including shea butter. 40 A traditional shea butter melts at body 35 temperature and is completely melted at 30 temperatures above 40˚C. This means that 25 there are no shea butter solids remaining to 20 15 stabilise a formulation at this temperature. 10 At room temperature, pure shea butter can 5 be fairly hard, especially if stored under Solid phase content (%) 0 non-optimal conditions. Traditional shea 15 25 35 45 butter also requires a good temperature Temperature (˚C) Lipex Sheasoft Ref shea butter control when the formulation is cooled, especially if the shea butter content in Figure 1: Melting profile of traditional shea butter versus Lipex Sheasoft. the formulation exceeds 2% to 3%. If the cooling process is not carefully controlled, levels of triterpene esters possess anti- moisture barrier in different ways as they there is a risk that the formulation inflammatory and fibroblast proliferating vary in polarity and solubilising power due develops large crystals on the surface, properties, shown in in vitro skin models. to variations in their chemistry. Emollients a phenomenon known as “bloom”. In the advanced shea butter, the triterpene also tend to interact differently with both Lipex Sheasoft, referred to subsequently esters normally vary between 5% to 7% other ingredients in the formulation as as the advanced shea butter, was which is slightly higher than in the well as skin constituents. developed to improve the heat stability of traditional refined shea butters. To carry out the pilot moisturisation body butters and lip treatments. It has a study, 10 women aged between 22 and 56 comparably high solids content at 40˚C Verifying moisturising were recruited from laboratory and office to 45˚C, stabilising the formulation at properties staff. Three areas of 3 cm x 5 cm were these temperatures. At the same time, The moisturising properties of the advanced marked on the left inner forearm of each the solids content at 25˚C to 35˚C is low, shea butter have recently been evaluated test person and washed by swabbing with making a soft and plastic material with in a pilot study. The aim of the study was ethanol. The three areas were randomised good spreadability and good skin softening to investigate whether shea butter had any for the three different treatments: A – shea properties. The skin feel of the advanced benefits over a conventional emollient in butter, B – hydrocarbon emollient and shea butter is perceived as dryer and richer short-term moisturisation on skin which C – no emollient. The shea butter in compared to traditional shea butter due has been challenged by intense washing. this study was Lipex Sheasoft and the to the elevated solids content at body Frequent washing is common today and hydrocarbon emollient was isohexadecane. temperature. repeated removal of the superficial skin All emollients were applied neat, without The advanced shea butter also solidifies lipids can lead to increased stress on the additives, emulsifiers or solvents. rapidly and stabilises in the desired beta skin resulting in increased trans-epidermal Immediately after the ethanol had crystal form very rapidly compared to other water loss and lower moisture content in evaporated, 4 mg to 5 mg of emollient was shea butters. This makes the manufacturing the skin. A rapid re-lipidisation and applied to the test area and rubbed gently process easy and gives long shelf life to re-moisturisation is then desired and into the skin, covering the test area as formulations without the risk of bloom application of a suitable skin care cream completely as possible. The test areas or changes in consistency and visual or is recommendable to help the were to be kept open and free of clothing appearance over time. skin recover from the challenge. However, over the test period. The subjects emollients are expected to give different were called for measurement of the No rancidity degrees of moisturisation, and build up the transepidermal water loss and skin All Lipex shea butters are refined and deodorised in order to remove pro-oxidative Table 2: Body lotion contaminants and precursors of rancidity. Trade name INCI name Content (%) The oxidative stability of the advanced shea butter focused on in this article Lipex Sheasoft Butyrospermum parkii 3.0 is reasonably high as the level of Lipex 205 Butyrospermum parkii 5.0 polyunsaturated fatty acids is low in Lipex L’sens Soybean glycerides (and) shea butter. The Oxidative Stability Index Butyrospermum parkii butter unsaponifiables 3.0 is around 20 hours at 110˚C, indicating Akomed R Caprylic/capric triglycerides 5.0 a shelf life of more than 2 years in a Akoline PG 7 Polyglyceryl-3 stearate 3.5 formulation without rancidity and odour development. Akoline MD50 Glyceryl stearate 1.0 Akoline SL Sodium stearoyl lactylate 0.2 Anti-inflammatory and skin repair action Glycerin 5.0 from shea butter triterpene esters Xanthan gum 0.1 The content of bioactive triterpene esters Preservative and perfume q.s. in shea butter varies between 2% to 7% Water Aqua To 100 depending on the origin and the quality of NaOH 20% in water To pH 6.5 the shea kernels, and the initial content can also be increased by different processes This body lotion combines Lipex Sheasoft with a liquid shea butter and caprylic/capric triglycerides such as solvent fractionation or molecular to produce an easily absorbed and soft lotion. Lipex L’sens increases moisturisation by binding water in liquid crystals together with the natural emulsifiers in the Akoline range. distillation. Shea butters with elevated

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11.5 40 11.3 11.1 35 ) 2 10.9 m

* 30 10.7 10.5 25 10.3 10.1 20 TEWL (g/h 9.9

Corneometer (a.u.) 15 9.7 9.5 10 BG ETH Ih 2h 3h 4h BG ETH Ih 2h 3h 4h

Lipex Sheasoft Isohexadecane Lipex Sheasoft Isohexadecane

Figure 2: TEWL and Corneometer results.

moisturisation in the treated areas once washing does not change the water Lipex Sheasoft is recommended to per hour for 4 hours after the application. content in the layer sensitive to be used in concentrations starting at Background measurements were made on corneometer measurements. Again the 1% in any type of product in the test areas before and after washing two tested emollients gave different results. combination with other emollients. Added with ethanol. Application of the advanced shea butter at 2% to 3% of the formulation the effects A Courage+Khazaka MPA 5 system gives an increase in the skin moisture of the higher melting point and higher equipped with Tewameter 300 and already at the first measurement 1 hour solids content start to influence both Corneometer CM 825 probes was used after application and the effect is persistent formulation consistency and skin feel. If for all evaluations. Readings were taken over the 4 hour test period. The further high temperature stability is desired, until a stable signal was obtained and the isohexadecane did not give any increase concentrations up to 5% to 10% can be average of minimum 20 readings were in the corneometer values, acting more used. Lipex Sheasoft combines well with used as the measured value. as an emollient and less as moisturiser. other emollients, especially esters and The data were checked for consistency The difference observed between the vegetable oils. A polar emollient with low and outliers before the means of two tested emollients shows that the viscosity, such as a branched chain ester, transepidermal water loss and corneometer molecular structure and the can be used to increase the spreading and values were calculated. physicochemical properties of individual skin absorption if a lighter formulation is The results show that ethanol washing, emollients will have a strong influence on desired. Using a combination of Lipex as expected, immediately increases the the moisturising properties of a formulation. Sheasoft and the liquid shea butter trans-epidermal water loss of the treated When formulating a skin care cream, both Lipex 205 makes it possible to optimise areas. In areas treated with the advanced aesthetics, as well as moisturisation and the shea butter content and skin feel shea butter, the trans-epidermal water emolliency, must be optimised and here of the formulation. loss is restored to the starting values the advanced shea butter offers an Anhydrous formulations such as lip after about two hours after application. ingredient with many possibilities. balms can be made from starting with A strengthening of the moisture barrier is Lipex Sheasoft in combinations with natural observed after 3 to 4 hours, observed Applications in formulating and liquid emollients. Formulations as further decreasing trans-epidermal Shea butters have traditionally been used with high shea butter content need to be water loss values. In comparison, the in skin care creams and as bases force-cooled to a final product temperature isohexadecane did not give the rapid trans- for body butters and as ingredients in of 22˚C to 24˚C for optimal stability. epidermal water loss recovery observed with and after-sun products. With The lip balm formulation shown in the shea butter and still after 4 hours the its higher melting point and semi-solid Table 3 combines Lipex Sheasoft with values were higher than the starting TEWL. consistency, the advanced shea butter Lipex Shea as the base for the formulation. A similar effect was seen in the skin is ideal for formulating heavier creams, Beeswax is used to start the solidification moisture measurements. A non-repeated lotions and butters but it can also be and to further increase the high ethanol washing does not influence the applied to make lip balms and other temperature stability. Other natural waxes immediate corneometer values as the anhydrous formulations. such as carnauba or candelilla can be exchanged for beeswax as they also have Table 3: Lip balm. good compatibility with Lipex Sheasoft. Trade name INCI name Content (%) Conclusion Lipex Sheasoft Butyrospermum parkii 27.0 Lipex Sheasoft is a unique shea butter Lipex Shea Butyrospermum parkii 8.0 for unique formulations. It has a proven Akorex L 49.8 immediate moisturisation and skin barrier Lipex Omega 3/6 Olus oil (and) Camelina sativa 5.0 enhancing effect, making it an ideal emollient for a variety of applications Beeswax 5.0 within advanced skin care. Akoline PGPR Polyglyceryl-3 polyricinoleate 5.0 The soft consistency, combined with 0.2 a high melting point, offers the formulator This lip balm formulation combines two shea butters in an optimal blend for softening the lips many ways to optimise both skin feel and has a consistency suitable for packaging in a tube. Akorex L and Lipex Omega 3/6 give and high temperature stability – without soothing and protecting effects from high levels of vitamin E, omega-3 and omega-6 fatty acids. compromising long shelf life and attractive Akoline PGPR adds shine and binds moisture. appearance. P C

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