化学机械浆制浆原料热水溶出物的抗氧化性及结构解析OA

In this study,hot water residues from six kinds of eucalyptus(Ea-Ef)and two kinds of acacia(Aa and Ab)thermomechanical pulps(TMP)were prepared,and their antioxidant differences were compared.The types and structures of substances contained in the hot water residues were analyzed by non-targeted/targeted liquid chromatography-mass spectrometry(LC-MS)techniques.The structures of substances with antioxidant properties were analyzed,and the content of key antioxidant substances was quantitatively determined.The results showed that compared to single-stage bleaching(s),the bleachability of the same wood species was significantly improved under washing and bleaching(w)and the highest whiteness increased by 4.80 percentage points.The hot water residues from Eucalyptus e(Ee)had the strongest antioxidant properties,the half maximal inhibitory mass concentration(IC50)of DPPH free radical was 33.29 mg/L,which was stronger than the commercial antioxidant BHT(IC50 value was 47.38 mg/L).Meanwhile,not only phenolic hydroxyl groups but also multiple conjugated structures contributed significantly to the antioxidant properties.By comparing the content of substances that could provide antioxidant properties,it was found that the hot water residues from eucalyptus c(Ec)had the highest content of ellagic acid,and the mass fraction was 161.51 mg/kg.