Cosmetically active ingredients are key elements in cosmetic formulations. Among them, biological macromolecules such as proteins and peptides, are often incorporated into cosmetic products. These molecules have a wide range of effects on skin and hair, including regenerative, moisturising and antimicrobial effects. They also contribute to maintaining the skin elasticity and strengthening and restoring the hair. Well-known proteins, used in cosmetic products, include whey, silk and wheat proteins, which differ in origin, composition and method of extraction, influencing their functional properties within cosmetic formulations.
In the diploma thesis, we developed and optimised cosmetic formulations with incorporated whey, silk and wheat proteins. In the initial phase of development, the shampoo formulations were optimised for the incorporation of the selected proteins as cosmetically active ingredients. Sodium lauryl laureth sulphate was used as the primary surfactant. Furthermore, the optimum concentration of the secondary surfactants in the shampoo, namely sodium lauroylglutamate and/or sodium lauroylsarcosinate, was determined. This was followed by the determination of the appropriate amounts of proteins to ensure suitable physico-chemical and organoleptic properties of the formulations.
Next, four optimal shampoo formulations were selected and subjected to stability tests. Their rheological features (rotation, amplitude, and frequency), pH values and organoleptic properties were determined. The samples were stored at room and elevated temperature (40 °C) for a period of three weeks. They were evaluated at time zero, after one and three weeks. After the three-week stability study, it was found that wheat proteins had the greatest influence on the organoleptic properties. An unpleasant odour was present and intense colouring was observed. The individual proteins also had an effect on the viscosity of the shampoo; the shampoo with added wheat proteins showed the lowest viscosity. The formulations produced were considered stable on the basis of preliminary tests. In the final stage, we added a pigment and an odour corrector to the shampoos to improve the sensory and aesthetic properties of the products.
It can be concluded that all four shampoo formulations show adequate stability, irrespective of the type of proteins incorporated. It would be worthwhile to build on these results in the context of long-term stability studies.
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