Pectin modification assisted by nitrogen glow discharge plasma

Abstract

This study is concerned with modification of high methoxy pectin (HMP) assisted by nitrogen AC glow discharge plasma. Intrinsic viscosity of plasma treated pectin (PTP) was measured as primary index for structural changes in pectin molecules at different plasma conditions. The intrinsic viscosity of pectin increased within 7 min of exposure to plasma treatment and then remained constant. According to Fourier Transform Infrared Spectrometry (FT-IR) analysis, the intensity of carboxylate peaks increased in PTP samples due to de-esterification of pectin. Moreover, by decreasing the degree of esterification (DE) in PTP samples, the results of FT-IR were confirmed. Based on high performance size-exclusion chromatography (HPSEC) analysis, the molecular weight of PTP reduced. PTP gel had higher storage and loss modulus and shorter linear viscoelastic region. Moreover, X-ray diffraction (XRD) studies indicated an increase of crystallinity in PTP due to the formation of hydrogen bonds. Results revealed that nitrogen AC glow discharge plasma had significant influence on physicochemical and functional properties of pectin. The result of this study showed AC glow discharge plasma has promising potential towards modification of pectin.

Keywords: AC glow discharge plasma; Modification; Pectin.