Physicochemical characteristics and functional properties of high methoxyl pectin with different degree of esterification

• Published in: Food chemistry Vol. 375; p. 131806
• Main Authors: Liang, Wan-ling, Liao, Jin-song, Qi, Jun-Ru, Jiang, Wen-xin, Yang, Xiao-quan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2022
• Subjects: Alkali de-esterification; Degree of esterification; Esterification; Functional property; High methoxyl pectin; Molecular Weight; Pectins; Physicochemical characteristic; Viscosity; High methoxyl pectin; Functional property; Alkali de-esterification; Physicochemical characteristic; Degree of esterification
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.131806

[Display omitted] •Alkali de-esterification increased negative charges and decreased molecular weight of HMP.•HG content decreased while RG-I increased after alkali de-esterification.•HMP with different DE has similar structural characteristic in FTIR, 1H NMR and XRD.•Gel property and emulsifying capacity of HMP decreased with the decrease of DE. Moderate alkali de-esterification can change the physicochemical characteristics and thus the functional properties of high methoxyl pectin (HMP). The results revealed that de-esterification could increase negative charges (Zeta potential from −21 to −31 mV), decrease molecular weight (from 448 to 136 kDa) and apparent viscosity of HMP. Homogalacturonan (HG) content decreased (from 62% to 49%) while rhamnogalacturonan Ⅰ (RG-Ⅰ) content increased (from 32% to 46%) after de-esterification. The group characteristics of HMP with different degree of esterification (DE) were similar and no obvious impact was made on degree of crystallinity by alkali de-esterification. A conformation transition of HMP molecule implied by Congo red test were occurred as the DE decreased. With the decrease of DE, the molecular structure of HMP became shorter and smaller, and the entanglement was weaker. The de-esterification caused slight decrease of thermal stability. Alkali de-esterification would weaken the gel property and the emulsifying ability of HMP.