Vegetal-derived Emulsifiers for Improved Stability and Formula Efficiency

Aug 1, 2011 | Contact Author | By: Luigi Rigano, Studio Rigano Industrial Consulting Laboratories
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Title: Vegetal-derived Emulsifiers for Improved Stability and Formula Efficiency
naturalx organicx emulsifierx potassium olivoyl hydrolyzed oat proteinx sodium olivoyl glutamatex
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Keywords: natural | organic | emulsifier | potassium olivoyl hydrolyzed oat protein | sodium olivoyl glutamate

Abstract: The quest for PEG-free surfactants and emulsifiers has led to new classes of vegetal-derived, ethylene oxide-free ingredients for environmentally friendly personal care products. Two such ingredients, described here, are based on the combination of olive oil and vegetable proteins with the first derived from oat and the second, with glutamic acid. These materials provide mildness and skin protection benefits.

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L Rigano, Vegetal-derived Emulsifiers for Improved Stability and Formula Efficiency, Cosm & Toil 126(8) 578 (2011)

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The modern concept of wellness is viewed as a balance between respect for the body/skin’s equilibrium and environmental responsibility. Thus, the success of natural-origin ingredients relies upon two key aspects that are linked in a cause-effect relationship. First is the consumer demand for natural and organic products that are safe, do not cause damage to the environment and provide the benefits of natural ingredients. Second is the development of formulas that are as compatible as possible with the physiology of skin and its annexes, without causing any adverse effects or exhibiting allergic potential.1 Although consumers are positively influenced by the growing environmentally friendly lifestyle, they will not accept substandard performances from new products compared to those with which they are familiar. Therefore, formulators are challenged to improve the technologies and strategies of their formulations using only what nature has to offer.

In the search for ingredients such as vegetable oils, waxes, actives, functional ingredients and conditioning agents that can be marketed as environmentally friendly, some categories such as emulsifiers, surfactants and fragrances are forgotten due to the intrinsic difficulty of combining the required high-tech efficacy/functionality with advanced environmental protection.

These are, however, essential in the formulation process in order to guarantee shelf life and to give, preserve and emphasize the sensorial experiences that a cosmetic product must perform. Frequently, the replacement of these ingredients is not easy and the number of emulsifiers that are Ecocert-certified or suitable for an eco-label certification is limited. Thus, the formulator is forced to overcome many difficulties in order to achieve a compromise in terms of stability; in many cases, however, the desired sensorial performance is not reached.

In relation, the aim of the present study was to develop organic, natural and standard formulations using two new emulsifier ingredients of vegetal origin that are Ecocert-certified and that exhibit sensory profile performances equal to formulas made using traditional emulsifiers. This study is focused on the development of these ingredients, using them to optimize the stability of formulations and evaluating the sensorial performances of the final formulas.2

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Table 1. Comparison of olive oil to common edible oils

Table 1. Comparison of olive oil to common edible oils

Table 1 shows the average composition of olive oil, compared with the most commonly used edible oils.

Table 2. Results obtained from oils with different polarity

Table 2. Results obtained from oils with different polarity

To evaluate the effects of oil phase polarity on the POHOP emulsion, oils having increasing polarity, shown in Table 2, were used to prepare emulsions with POHOP (5%).

Table 3. Results obtained from oils with different polarity

Table 3. Results obtained from oils with different polarity

Indeed, the best performances were obtained with medium polar oils such as C12–15 alkyl benzoate and dicaprylyl carbonate, and partially with polar oils such as sweet almond oil (see Table 3).

Figure 1. Olea europaea (Olive), a species of a small tree of the family Oleaceae

Figure 1. <em>Olea europaea</em> (Olive), a species of a small tree of the family Oleaceae

Considering these benefits, extra-virgin olive oil was chosen and obtained by cold pressing the pulp of the fruits of Olea europaea (olive), a species of a small tree of the family Oleaceae native to the coastal areas of the eastern Mediterranean region, which is pictured in Figure 1.

Figure 2. Chemical structure of POHOP

Figure 2. Chemical structure of POHOP

This material is derived from hydrolyzed oat protein and has a hydrophilic head (see Figure 2).

Figure 3. Evaluation of TEWL for different solutions with and without POHOP

Figure 3. Evaluation of TEWL for different solutions with and without POHOP

As seen in Figure 3, increasing POHOP from 0.5% to 2.5% did not decrease the TEWL%.

Figure 4. Chemical structure of SOG

Figure 4. Chemical structure of SOG

The second emulsifier links sodium olivoyl glutamate (SOG), a vegetal-derived glutamic acid, was linked to the olive oil fatty chains to obtain a hydrophilic head (see Figure 4).

Figure 5. Evaluation of the emulsion fineness by microscope

Figure 5. Evaluation of the emulsion fineness by microscope

Figure 5 shows the three main variations in appearance of the emulsions, which were used for comparison purposes to evaluate all formula samples for particle size and homogeneity.

Figure 6. Evaluation of emulsion stability by centrifuge

Figure 6. Evaluation of emulsion stability by centrifuge

Figure 6 shows the three main variations in appearance of the emulsions, which were used for comparison purposes to assess all formula samples for stability.

Figure 7.The three types of production methods

Figure 7.The three types of production methods

The next step was to evaluate the order of addition of the various emulsion components, as shown in Figure 7.

CT1108 Footnotes Rigano

a Olivoil Avenate Emulsifier (INCI: Potassium Olivoyl Hydrolyzed Oat Protein (and) Cetearyl Alcohol (and) Glyceryl Oleate (and) Glyceryl Stearate (and) Water (aqua)) is a trade name of Kalichem Italia s.r.l., Botticino Sera, Italy.
b Olivoil Glutamate Emulsifier (INCI: Cetearyl Alcohol (and) Glyceryl Stearate (and) Sodium Olivoyl Glutamate (and) Water (aqua)) is a trade name of Kalichem Italia s.r.l., Botticino Sera, Italy.
c The Optical Microscope, Eyepiece W15-13mm, Objectives 40xRM, is manufactured by Swift Instruments, Carlsbad, Calif., USA d The Multifuge 1 S-R is manufactured by Heraeus, Kendro, Germany.

Formula 1. Eye Contour Cream

Formula 1. Eye Contour Cream

Finally, sensory assessments were made by a panel of trained experts who evaluated all formulations prepared with the different oils and different polarities, including two final formulations—an eye contour cream (see Formula 1) and a lenitive face cream (see Formula 2).

Formula 2. Natural Face Lenitive Cream

Formula 2. Natural Face Lenitive Cream

Finally, sensory assessments were made by a panel of trained experts who evaluated all formulations prepared with the different oils and different polarities, including two final formulations—an eye contour cream (see Formula 1) and a lenitive face cream (see Formula 2).

Formula 3. Sunscreen SPF ~= 30

Formula 3. Sunscreen SPF ~= 30

Additional formulations (see Formulas 3 and 4) were then prepared to test the emulsification properties of the two emulsifiers further and assess their range of application.

Formula 4. Organic Anti-aging Cream

Formula 4. Organic Anti-aging Cream

Additional formulations (see Formulas 3 and 4) were then prepared to test the emulsification properties of the two emulsifiers further and assess their range of application.

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