Thermoanalytical characterization study of hair from different ethnicities

Lima, Cibele Rosana Ribeiro de Castro; Almeida, Mariana Mandelli de; Velasco, Maria Valéria Robles; Matos, Jivaldo do Rosário

doi:10.1007/s10973-015-5070-6

Cited by 11 publications

(9 citation statements)

References 43 publications

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“…Exposure of the fibre to excessive heat has therefore caused the thermal decomposition of the protein material [31], leading to the appeareence of a yellowish color due to this thermal decomposition, which leads us to consider that part of the disulfide bridge (SS bond), the CS and CC bonds of the polypeptide backbone and the Amide III (related to the secondary protein structure) bonds were broken. It can be inferred that permanent damage was hence caused to the hair, since these are important bonds of the α-keratin protein, which provide shape, resistance and flexibility, among other characteristics of the fibre [5].…”

Section: Resultsmentioning

confidence: 99%

Raman spectroscopy and electronic microscopy structural studies of Caucasian and Afro human hair

Santos

Edwards

Oliveira

2019

Heliyon

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Human hair fibre is subjected to various structural modifications due to the application of chemicals such as dyes, shampoos and bleaches and/or physical procedures such as heating, and often more than one procedure is performed on the same hair. The present work aims to analyze the changes incurred in hair samples of two ethnic groups, namely Caucasian and Afro, before and after different treatments such as thermal, bleaching and straightening. In addition to observing the damage caused by each treatment separately, the study of samples that received all three treatments was carried out. For molecular structural characterization, the Raman vibrational spectroscopic technique was used and scanning electron microscopy (SEM) was used for morphological analysis of the hair fibres. This investigation has shown, through vibrational spectroscopy, that several important bonds have been modified, such as the S-S, C-S, C-C and S-O bonds as well as the secondary structures of proteins that have indergone changes in their conformation as a result of the treatment. Hair from the two ethnic groups showed small differences in relation to each applied treatment. Excessive heat generated a higher rate of Raman spectral band intensity changes when compared to the other treatments and it was observed that the action of several treatments on the same hair fibres resulted in even more pronounced structural changes. Finally, scanning electron microscopy showed that each treatment caused a different morphological deformation pattern on the capillary surface of the human hair.

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Section: Resultsmentioning

confidence: 99%

Raman spectroscopy and electronic microscopy structural studies of Caucasian and Afro human hair

Santos

Edwards

Oliveira

2019

Heliyon

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“…the diameter at twisting points is smaller than at other areas . Nevertheless, this type of hair is more susceptible to chemical transformation like hair straightening and procedures evolving heat, such as brush and flat iron with the aim of changing the shape of the hair. However, there is a lack of information regarding the extent of the damage caused by chemical and physical treatments performed on Afro‐ethnic and Caucasian hair with different degrees of curliness.…”

Section: Introductionmentioning

confidence: 99%

Chemical and physical treatments damage Caucasian and Afro‐ethnic hair fibre: analytical and image assays

Bloch

Goshiyama

Dario

et al. 2019

Acad Dermatol Venereol

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Background Sensory and structural characteristics of hair can be modified by chemical and physical treatments, as dyeing, brushing, but also by external factors, as sunlight radiation. However, quantitative data relating damage to the degree of hair curliness and treatments are missing. Objective To evaluate the effect of chemical and physical treatments on different types of hair. Methods In this study, we compared the effects of bleaching/dyeing, thioglycolate‐based straightening, brushing/flat iron and UVA/Vis radiation on different types of hair: Caucasian (straight dark brown, straight blond, wavy dark brown and curly dark brown) and Afro‐ethnic hair. Results Bleaching/dyeing and UVA/Vis radiation increased combing work of Afro‐ethnic hair tresses, indicating damage to the cuticle scales, which was confirmed by SEM images. Further, bleaching/dyeing caused wear on cuticles with high protein loss and reduction on the tryptophan content, independently of the hair curliness, which characterizes those procedures as very aggressive to hair structure. Straightening using ammonium thioglycolate, due to the oxidative treatment evolved, caused significant colour fading in brown/black tresses, while UVA/Vis radiation affected the colour of only blond hair tresses since they are poor in eumelanin, the photoprotective and photostable melanin molecule. Conclusion The combination of analytical and image techniques contributed to understanding how the hair shape is related to the type of damage caused by several chemical and physical treatments. These findings contribute to the development of safety cosmetics that insure the beauty of curly hair, both Caucasian and Afro‐ethnic hair.

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“…In both peaks, the values are similar among the three different fibres. Some authors found lower denaturation peaks for the African fibres 27 . Denaturation temperatures normally shift towards higher values with damage (cystine oxidation), whereas the denaturation enthalpy decreases 44 .…”

Section: Resultsmentioning

confidence: 99%

“…As the TG detects events associated with mass loss, the DSC indicates the thermal events related to mass variations 25 . Several authors, who focused on the thermal analysis of human hair, executed TG and DSC analyses with the purpose of characterizing the keratin of human hair 27,28 and verifying the effects of hair care products on the keratin structure 25,26 . Lately, these techniques have been applied to differentiate the hair samples of different ethnicities 27 ; however, slight variations were found.…”

Section: Introductionmentioning

confidence: 99%

Ethnic hair: Thermoanalytical and spectroscopic differences

Oliver

Coderch

Carrer

et al. 2020

Skin Research and Technology

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Hair is a protein fibre (85%) and contains low levels of lipids (1%-5%) and water (10%). Hair consists of a follicle and a shaft. 1 The shaft, the part of the hair that is visible above the skin, has a width of 50-100 μm and is composed of three main parts: the medulla, the cortex and the cuticle. The medulla, which possesses a diameter of 5-10 μm, is composed of loosely packed cells and is not always presented in the hair. The cortex, which is 45-90 μm thick, accounts for 90% of the total hair mass. Seven to ten tetramer spiral units, known as intermediate filaments, compose the microfibrils of the cortex. The intermediate filaments are surrounded by a matrix of high-glycine/tyrosine proteins. The proteins interact with the intermediate filaments through intermolecular disulphide bonds that provide inertness, rigidity and high mechanical strength to the hair fibres. 1,2 The cuticle, at the surface of the hair, has a 5-µm-thick protective covering consisting of superimposed layers of flat overlapping structures. 3,4 Low levels of lipids form part of the intercellular membrane complex, and these lipids are presented in the cortex and in the cuticle. In addition, the hair medulla also contains a fraction of rich lipids. 5,6 The presence of cuticles is fundamental to maintain the internal water content of the

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Thermoanalytical characterization study of hair from different ethnicities

Cited by 11 publications

References 43 publications

Raman spectroscopy and electronic microscopy structural studies of Caucasian and Afro human hair

Raman spectroscopy and electronic microscopy structural studies of Caucasian and Afro human hair

Chemical and physical treatments damage Caucasian and Afro‐ethnic hair fibre: analytical and image assays

Ethnic hair: Thermoanalytical and spectroscopic differences

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