96 TEXTURES


Plant fibres: emulsions without emulsifiers


Dr. Sabilla Digel – Berg+Schmidt


Emulsions are everywhere in daily life, and serve as a base technology for products in the food, cosmetics, and pharmaceutical industries. Whether in creams, lotions, sauces, or drug delivery systems, the stabilization of emulsions is traditionally ensured with the aid of surface- active molecules or polymers to prevent coalescence of the droplets. However, growing consumer demand


for sustainable, natural, and skin-friendly alternatives has led to the development of innovative emulsion stabilizers. One such approach is the use of Pickering emulsions— emulsions stabilized by solid particles that adsorb irreversibly at the oil-water interface. Pickering emulsions were first described in the early 20th century by Ramsden W1 SU2


and Pickering (1903 and 1907 respectively), and their


practical applications are still numerous today. While in conventional emulsions surface-


active molecular emulsifiers orient themselves at the water-oil interface depending on their lipophilic and hydrophilic moieties, Pickering emulsions are stabilized by solid particles that adsorb irreversibly at the oil-water interface, creating a physical barrier to droplet coalescence. These emulsions are known for their


exceptional stability,3 good skin compatibility, and ability to provide sophisticated and PERSONAL CARE March 2025


appealing sensorial properties on the skin. A promising approach to Pickering


emulsifiers exploits the potential of using fibres and hydrocolloids that are widely used in the food industry, as their unique properties can be exploited to solve challenges in cosmetic applications, and to create innovative textures while improving environmental sustainability. This article describes our research on


developing plant fibre-based materials for the stabilization of Pickering emulsions in cosmetic applications by combining the synergistic properties of fibres and hydrozzzzzcolloids. In the following sections, we detail the design,


characterization, and application of these plant fibre-derived materials, demonstrating their effectiveness in stabilizing emulsions while meeting the increasing demands for sustainability and performance in the modern cosmetic industry.


Synergistic plant fibres open doors to different textures The journey toward creating innovative fibre-based emulsifying agents for cosmetic applications begins with an understanding of the wide selection of available plant fibres. In an extensive examination of raw materials from different plant sources, we assessed their


suitability to stabilize emulsions, first individually and then in the form of fibre mixtures.


Key considerations in fibre selection In the screening process, we addressed a variety of critical factors to identify plant fibres that meet the high standards of cosmetic formulations: ■ Sensory properties: Fibres with undesirable characteristics, such as visible colour or particles that can be perceived when distributed on the skin, were excluded early in the selection process. ■ Emulsion stabilization: The fibres’ ability to stabilize O/W emulsions under common shear rates was tested. ■ Thickening and gelling: Beyond emulsification, many fibres are able to thicken or gel the water phase, contributing further to stabilizing cosmetic emulsions. ■ Surface properties: The hydrophilic and hydrophobic balance of fibres, characterized by contact angle measurements using the sessile drop method. The contact angle θ indicates how the solid particle wets the oil and water phases. At θ < 90° the particle is more hydrophilic and prefers the water phase. At θ > 90° it is more lipophilic and prefers the oil phase. If θ is < 90° but close to 90°, the particle is amphiphilic, having the ideal properties to stabilize O/W emulsions (Figure 1).4


www.personalcaremagazine.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104