Biochemical and Structural Characterization of Ferulated Arabinoxylans Extracted from Nixtamalized and Non-Nixtamalized Maize Bran.

Abstract

Maize bran is a good source of non-starch polysaccharides, having various bioactive compounds. In the current research, we extracted the ferulated arabinoxylans from nixtamalized maize bran (NMB) and non-nixtamalized maize bran (NNMB) and explored their biochemical composition (monosaccharides, phenolic compounds) and structural characteristics (FTIR, SEM and XRD) as well as antioxidant activity. Results showed that contents of ferulated arabinoxylans were 8.1 ± 0.04% and 6.8 ± 0.02 in NMB and NNMB, respectively. Moreover, the purity of arabinoxylans was 60.1 ± 0.8% and 57.04 ± 0.7% in NMB and NNMB ferulated arabinoxylans. Furthermore, ferulated arabinoxylans have higher arabinose, xylose and ferulic acid contents. FTIR spectra of NMB and NNMB ferulated arabinoxylans depicted the presence of polysaccharide compounds and the corresponding band was observed at 993 cm-1, which is due to glycosidic bond vibration. In addition, absorbance regions of arabinoxylans between 900 cm-1 to 1200 cm-1 were observed. Moreover, SEM micrographs of ferulated arabinoxylans had visible rough and porous surface morphology. Further, ferulated arabinoxylans of NMB and NNMB did not exhibit any sharp peaks in XRD graphs, attributed to their amorphous nature. However, XRD 2θ showed peaks at 20.0°, which predominantly indicated that the material has an amorphous state with small crystalline regions in the sample, which shows the presence of xylans (small and narrow sharp peaks).