Structural, physicochemical, and emulsifying properties of sweet potato pectin treated by high hydrostatic pressure and/or pectinase: A comparative study

Background: Sweet potato (Ipomoea batatas. L) is the sixth most important food crop in the world, and China is the largest producer. Large amounts of sweet potato residues during the starch extraction are generated, leading to environmental pollution and resources waste. However, these residues can be used as viable source for pectin extraction. As a natural biopolymer with high molecular weight and complex structure, the usefulness of pectin has been limited, which need to be modified in order to improve its physicochemical properties, thus expanding its applications in the food industry. Therefore, this study is conducted to modify the sweet potato pectin (SPP) using high hydrostatic pressure (HHP) and/or pectinase treatment, and to determine its effects on structural, physicochemical and emulsifying properties.

Results: The results demonstrated that the molecular weight of SPP decreased following HHP and pectinase treatment, which was evidenced using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The degree of esterification was also decreased confirmed by decreased absorbance intensity of the peak at 1739 cm^-1 in the fourier-transform infrared (FTIR) spectrum and decreased peaks at 3.6 and 3.8 ppm in the ¹ H nuclear magnetic resonance (NMR) spectra. Moreover, the content of monosaccharides, uronic acids, and emulsifying properties were increased after HHP and pectinase treatment.

Conclusion: These results concluded that HHP-assisted pectinase treatment could be used as novel technique for the modification of pectin with great potential for application in the food industry with better emulsifying properties. This article is protected by copyright. All rights reserved.

Keywords: Sweet potato pectin; high hydrostatic pressure; pectinase; physicochemical properties.