34 HAIR CARE


Keratin @ 5% Figure 1: SEM images: Keratin versus Kerashaft V, leave-on treatments


Test protocols Hair conditioning Caucasian hair strands were bleached, to damage both the cuticle and cortex. Subsequently each strand was washed with shampoo, treated with 0.5 ml of sample and dried: the tresses were analyzed with four samples (hydrolyzed keratin solution, Kerashaft V solution, Kerashaft Q solution and control) and dried after five minutes. Additional assessment was made on


Caucasian hair, comparing longitudinal and transversal sections of virgin hair subject to bleaching. Homogeneous locks were collected, standardized in number, weight, and length. The analysis was carried out in a closed room, at controlled temperature and humidity at the same time of day. All the strands were subject to washing with a 3% (v/v) solution in SLES- purified water, to remove dirt and cosmetic products. Afterwards, the washed and dry hair, after a stationing time of 24 hours, was divided into two groups for each type, treated and untreated. Treated hair was then put in contact for five minutes with a serum, subsequently subject to drying with hairdryer for five minutes; the untreated hair is directly subject to analysis. The images of virgin hair, dyed and bleached, treated and not, were compared through scanning electron microscopy (SEM).


Restructuring, hydration and luminosity actions A lock was subject to washing with common shampoo, dried with hairdryer and subsequent plate at 220 °C in order to obtain the reference standard. The same treatment was made on locks treated with three samples: 0.5 ml Kerashaft V, hydrolyzed keratin and Kerashaft Q solutions, each of them used at 5%. Additional studies aimed to evaluate the


comparison against a market benchmark based on vegetable derived protein hydrolysate were carried out. In this case, the treatment was made using both the active object of the study and the benchmark at a 1.5% dosage; before this treatment, 12 tresses were subject to level- ten bleaching and chemical-physical damage through ammonium thioglycolate and hydrogen peroxide, followed by oven heating. The treated hair was placed on a pretreated


PERSONAL CARE January 2023


Control


Kerashaft @ 5%


Figure 2: SEM images: Kerashaft V leave-on treatment versus untreated bleached hair Untreated bleached Hair


slide and subject to polarized microscope analysis. The hair pictures before and after treatment were compared. Instrumental measurements in image quality were conducted with polarized light microscope and image recording. Keratin is a crystalline protein able to delay


the wave of polarized light; the hair shaft appears under the microscope as luminous and colourful on a black background. There are wave delays, visible as colours, “colours of polarization “, and due to the thickness of the keratin for which each colour, based to Newton’s scale, a precise diameter corresponds. Wave delays due to the crystallographic


orientation, and wave delays due to the pigment contained in the keratin, are referred to as ‘clearing colours’: visible colour implies a specific structural order and tidiness. This technique applied to trichology enables to observe the crystallographic hair structure. For hair restructuring and analysis of its


elemental composition, EDX microanalysis was carried out to provide the elementary analysis of the shaft samples before and after the treatments.


Bleached + Kerashaft @ 1.5% Thermogravimetric analysis allows to


determine the moisture content present in liquid, porous and solid substances. The thermobalances weigh and dry the sample through IR heater which weighs and dries at the same time the humidity, enabling to calculate the percentage value of the dry residue or aqueous content. Through constant measurements of weight variations during drying, the thermobalance allows to extract all the humidity present in a sample and calculate: initial weight, dry residual weight, and the initial percentage of moisture present. Further assessments were performed


through the quantification and comparison of the volume of virgin and treated hair with a base shampoo concentrated with 1.5% Kerashaft V. Homogeneous tresses were collected and prepared and standardizing by weight and length; the analysis was carried out in a closed room, at controlled temperature and humidity at the same time of day, after a standing time of about 24 hours. Hair tresses were treated with a 3% (v/v)


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