Application of an Enzymatic Method for Identifying Hair Treatments

Abstract

The purpose of this research was investigating the use of an enzymatic method for identifying various treatments, such as permanent waving, hair dyeing and bleaching used on hair from hair samples. Morphologically only negligible difference was observed between untreated hair and hair permed in vitro. However, after protease treatment, the degradation of permed hair was accelerated and a significant difference was observed between permed and untreated hair in morphology and degradation extent. The degraded fraction of untreated hair was confined to cuticle region of hair surface, whereas in hair samples permed and dyed in vitro, the microfibril protein of hair was degraded. Furthermore, there was a high correlation between the extent of degradation and the hair damage resulting from these chemical treatments. When we tested the method on human hairs from live subjects, no significant difference was observed on untreated hair in different hair sections. However, the tip section of permed and dyed hair showed much higher degradation than that of root section from morphology and degradation extent. Our findings for practical uses revealed that the enzymatic method can be applied to identify the chemical treatment used on hair.