Fragrance Retention in Virgin and Bleached Caucasian Hair.

Human hair, when bleached, undergoes oxidation of melamine granules and its structural proteins. This work aims to compare fragrance retention in both virgin and bleached hair, taking into consideration the interactions between fragrance compounds and hair before and after chemical modification. The bleaching process of straight dark brown Caucasian hair was carried out using a 4.5% wt. hydrogen peroxide solution at pH 9.5. Fragrance raw materials were incorporated in a shampoo formulation and applied on hair by washing, followed by rinsing. Hair was then let to dry under controlled conditions of temperature and humidity and the volatiles were collected by solid-phase microextraction and quantified by Gas Chromatography Mass Spectrometry (GC-MS). The more bleached the hair, the higher is the amount of sorbed substances during shampoo washing because of a higher number of holes in the hair structure, which increases its sorption capacity. Besides that, the impairments caused by oxidative reaction of hair surfaces are responsible for the faster evaporation of fragrant compounds and this behavior was compared with the loss of moisture of untreated and bleached hair.