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  • Stability test and sensory study in Helichrysum italicum emulsions varying the content of xanthan gum and oily phase : research work for master's thesis
    Romero Serrano, Guadalupe
    Helichrysum italicum also known as perpétuas das areias, perpétuas de Itália, immortelle or everlasting is a small aromatic shrub, with anti-inflammatory, anti-allergic and antimicrobial and ... antioxidant properties. The essential oil of this plant is commonly used at the cosmetic area due to the fact is recommended for sensitive and dry skin. It helps to reduces wrinkles, stretch marks, scars and it can also regenerate the skin. The aim of the study is to find the optimal composition of the day and night creams to achieve the most pleasant skin characteristics. Creams were prepared at the laboratory, with the necessary materials and devices and at room temperature (20-25%C). Four day creams were prepared, each one with a different content of xanthan (0%, 0,1%, 0,2% and 0,3%) and they were submitted to temperature test (7 temperature cycles, each one consist on 24 hours at 40%C, 24 hours at room temperature and 24 hours at 4%C). Organoleptic properties were measured before each cycle. Viscosity and pH were measured before and after the seven temperature cycles in order to find any physical, chemical or microbiological instability. Organoleptic properties for the day creams were the suitable ones; there was not a phase separation. The results in sample 2-4 indicated that was physical instability because viscosity values changed significantly from one measurement to another, but emulsions didn%t break down so it cannot be affirmed. Sample 1 has not significant change in its viscosity. PH decreased after the temperature aging due to a microbiological instability but sample 2 was still in the permitted range (5, 5+-0,5). Sensorial properties were evaluated by 20 volunteers, they completed a questionnaire and sample 3 (0, 2% of xanthan) was chosen as the best one. It has the best skin feeling. Three night creams were prepared with 0, 2 % of xanthan content due to the fact that it was chosen as the most suitable concentration to feel the best skin comfort in day cream. Each cream has a different content of jojoba oil and olive oil (10% and 3%; 6% and 7%; 3% and 10%, respectively). They were also submitted to temperature aging. Organoleptic properties were measured after each cycle. Viscosity and pH were measured before and after the 7th cycles. Organoleptic properties were not the adequate ones; it was a phase separation due to a possible microbiological or physical instability. Viscosity values increased from before to after the temperature aging this could mean that there was a physical instability. Changes in pH were minimal, all creams were in the permitted range (5,5%0,5), so it could be said that there wasn%t neither chemical nor microbiological instability. Sensorial properties were evaluated in the same 20 volunteers, who complete a similar questionnaire and choose the sample 2 (6% of jojoba oil and 7% of olive oil) as the one with best characteristics.
    Vrsta gradiva - magistrsko delo ; neleposlovje za odrasle
    Založništvo in izdelava - Ljubljana : [G. Romero Serrano], 2016
    Jezik - angleški
    COBISS.SI-ID - 4109425

Nobena knjižnica v sistemu COBISS.SI nima izvoda tega gradiva.
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