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Hydrolyzed Quinoa for Hair Repair and Gloss
By: Elzbieta Kasprzyk and Lauren DelDotto
Posted: December 1, 2010
As hair is exposed to daily stressors such as UV exposure, heat styling and frequent washing, it becomes dry and damaged. Quinoa Pro EX (INCI: Hydrolyzed Quinoa) is a hydrolyzed quinoa protein from TRI‐K Industries that is designed to bind to the hair shaft and penetrate the cortex, bringing moisture and repair deep into the hair. Further, it is paraben‐free and gluten‐free, making it ideal for natural and mild formulations.
Quinoa Pro EX confers not only film-forming and moisture-retention benefits that are typical of hydrolyzed proteins, it also penetrates the hair shaft and provides substantivity to repair and control damage as well as improves hair gloss, as are described here.
Substantivity of Quinoa Pro EX on Hair
To assess the level of surface and internal substantivity of Quinoa Pro EX on human hair fibers, six double-bleached Caucasian hair swatches each weighing 5.0 g and 25 cm long were prepared by cleansing with a 10% sodium lauryl ether sulfate (SLES) solution and rinsing. Treatment swatches were then submitted to a cycle of five applications of a 1% aqueous Quinoa Pro EX solution with a 10% SLES wash after each treatment; control swatches were washed and dried only.
To measure superficial fluorescence, hair fibers were soaked in a Rhodamine B dye (CI Basic Violet 10) solution (8 μg mL-1) for 20 min to mark the damaged sites of the hair, followed by rinsing swatches with deionized water for 1 min and drying them at 45°C for 15 min. This cationic dye reacts with the active sites of sulphonic acid, formed by cleavage of the cysteine S-S bond (disulfide bonds) that occurs during hair relaxation, bleaching and other treatments. A fluorescent complex is thus formed on hair fibers, which is detected when it is exposed under the fluorescence microscope coupled to filters compatible to the wavelength emitted. The hair fibers were then arranged along the length of a glass slide for optical microscopy and fifteen fluorescence images of longitudinal segments were obtained for each study group.
Analysis was also performed on the cross-sections of treated fibers. To measure cross-section fluorescence, hair fibers were embedded in acrylic resin according to the resin drying and curing procedures. After hardening of the resin, 10 µm-thick cross sections were made using a glass knife and ultramichrotome. The sections obtained were fixed on microscope slides before being immersed in the Rhodamine B dye.
Analysis of fluorescence microscopy was performed using a Leica Fluorescence Microscope with N2.1 cubic filters. Higher intensity fluorescence indicates greater amounts of dye attached to the damaged sites; thus when a product with high substantivity is applied to hair, the link between active ingredients and the damaged sites of the hair lowers the intensity of fluorescence.
After one treatment with Quinoa Pro EX, hair showed a 16% reduction (p < 0.05) in intensity of superficial fluorescence compared with the control, corresponding to improvement of damage to the outside of hair (see Figure 1). After five treatments with Quinoa Pro EX, compared with the control, hair showed a 32% reduction in superficial fluorescence (p < 0.05) and a 26% reduction (p < 0.05) in cross-section fluorescence (see Figures 2 and 3).
Effect of Quinoa Pro EX on Hair Gloss
Quinoa Pro EX was also evaluated for effects on hair gloss. Fifteen hair swatches were prepared from dark brown Caucasian hair and cleansed using 10% sodium lauryl ether sulfate (SLES) solution for 1 min then rinsed with running water. Swatches were dried in a standardized environment at 55 + 5% RH and 22 + 2°C for 24 hr before tests. Baseline gloss assessments were then taken for each swatch.
When light hits hair fibers, it spreads on irregular surfaces of the hair and absorbs and reflects in different directions. However, when light is reflected to the viewer at the same angle, it provides greater luminous intensity, known as gloss. For this study, the Glossmeter with a fixed incidence angle of 85 degrees was used to assess gloss.
After initial readings were taken, swatches were treated with either one or five applications of a 1% aqueous solution of Quinoa Pro EX and again measured for gloss. Five consecutive readings were taken in different positions to obtain average gloss values for each swatch and each group.
The swatches of hair submitted to treatments of both one and five applications of Quinoa Pro EX solution showed gloss values that were significantly higher than their baseline and the control. Compared with the control, one treatment with Quinoa Pro Ex improved the gloss value by 26% (p < 0.05), and five treatments improved the gloss value by 51% (p < 0.05) (see Figure 4).
Combability Assessment of Quinoa Pro EX
Finally, the wet and dry combability of hair swatches treated with Quinoa Pro EX were evaluated. Fifteen hair swatches were prepared from natural Caucasian hair. These were cleansed with a 10% sodium lauryl ether sulfate (SLES) solution for 1 min and rinsed. Swatches were dried in a standardized environment at 55 + 5% RH and 22 + 2°C for 24 hr before tests. Swatches used in the wet comb testing were re-wet with only water.
Swatches were then tested using a comb equipped with electronic sensors and software. Baseline measurements were taken for both the wet and dry combability of each swatch. Treatment swatches were submitted to a cycle of one or five applications of a 1% aqueous solution of Quinoa Pro EX and new measurements were taken.
In both wet and dry swatches, hair submitted to treatments of one and five applications of Quinoa Pro EX solution showed significantly lower values of combing energy required, compared with the baseline and control. In the case of wet combability, one treatment reduced the combing force by 27% (p < 0.05) while five treatments reduced it by 79% (p < 0.05) (see Figure 5). In the case of dry combability, one treatment reduced the combing force by 5% (p < 0.05) while five treatments reduced it by 83% (p < 0.05) (see Figure 6).
Quinoa Pro EX was shown to provide substantivity to hair and improve hair gloss and wet and dry combability. The results suggest application of the ingredient at 1-10% in shampoos, conditioners and leave-on treatments designed to repair hair after chemical treatments or for conditioning especially dry or ethnic hair.
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