Browsing by Author "Nancheva V."

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    Rheological properties of cosmetic compositions containing rosemary and grapefruit pulp and seeds extracts
    (2014-01-01) Petkova-Parlapanska K.; Nancheva V.; Diankov S.; Hinkov I.; Karsheva M.
    Modern cosmetic formulations represent a combination of synthetic and natural ingredients. Knowledge of the rheological behavior allows managing the structure and the quality of the products by means of supplement addition, regime change or mechanical and technological processing adjustment. The extraction from rosemary and grapefruit pulp and seeds with ethanol-in-water solutions is carried out in a thermostated shaker at 20°C. The total polyphenol content (TPC) and the antioxidant capacity (AOC) of the extracts are determined. The cosmetic compositions prepared are based on stearic acid, with 3-ethanolamine as emulsifier. Extracts are used as a preservative, instead of controversial lately methyl-parabens. The rheological behavior of the cosmetic formulations is studied. It is found that all compositions exhibited thixotropic flow behavior. The cosmetic emulsion containing an alcoholic extract of grapefruit seeds has different rheological behavior which may be described by the Bingham rheological model. This effect can be explained by the composition of the extract and its influence on the pH. It is found that the extract from grapefruit seeds has acidic properties and affects the pH of the medium. The cosmetic formulation with rosemary extract exhibits power low and thixotropic behavior. The purity of the cosmetic formulations was tested against E. Coli bacteria. It is found that no bacterial colonies are observed neither after one day, nor after three months of storage. It can be concluded that the natural extracts from rosemary and grapefruit seeds and pulp exhibit good antibacterial properties, being quite satisfactory substitute of the parabens.