Antioxidant Activity of Keratin Hydrolysates Studied by DSC

Abstract

Due to the high content of thio-aminoacids, (i.e., methionineand cysteine) and the structural intermolecular disulfide bonds,this study has focused on new biopolymer keratin antioxidants.The antioxidant activity of keratin hydrolysates in polyethyleneglycol (PEG) matrix has been studied using the differentialscanning calorimetry (DSC) under non-isothermal conditions.The experimental results have been evaluated and kineticdescription of the oxidation induction periods have been carriedout using the Bethelot-Hood temperature function. The lengthof induction periods has been assessed for all temperatures usingthe kinetic results. In order to compare the stabilizing effect ofkeratin hydrolysates, protection factors and antioxidanteffectiveness have been calculated. The results have shown thatthe antioxidant activity of keratins strongly depends on thehydrolysis process. The protection factors decreased withincreasing temperature and decreasing concentration of keratin.Based on our previous experience, we propose that the qualitativetrend presented in this work can also be applied for othermatrices than PEG. Keratin hydrolysates and their modificationswith antioxidant properties significantly reduced formaldehydeemissions from urea-formaldehyde adhesives.