Modification of pectin with high-pressure processing treatment of fresh orange peel before pectin extraction: Part II. The effects on gelling capacity and emulsifying properties of pectin

The most important functionalities of pectin are gelling and emulsifying properties, which can be tailored by modifying pectin structure through chemical/enzymatic treatments or physical processes. In a companion article (Zhao et al., 2023), the modification of pectin structure with high-pressure processing (HPP) was reported. In this study, the functionalities of the HPP-modified pectins (Hp) were evaluated and compared with commercial low methoxy (LM) and high methoxy (HM) pectins. The calcium sensitivity of Hp was comparable to that of commercial LM pectin, which was remarkably higher than the control pectin extracted from untreated peel and commercial HM pectin. Hp had a dramatically higher gelling capacity for calcium-mediated gelation than the control and commercial HM pectin. The strength and viscoelastic properties of Hp-calcium gels were comparable to that of commercial LM pectin. Meanwhile, most of the Hp also showed a comparable gelling capacity for sugar-acid-mediated gelation to that of the control and commercial HM pectin. Hp also had higher emulsifying stability than the control and commercial pectins. The increased capacity of Hp for calcium-mediated gelation was attributed to the block-wise distribution of non-esterified galacturonic acid (GalA) introduced by the HPP treatment, and the higher emulsifying stability was mainly attributed to the debranching of pectin. The study further confirmed that pectin functionalities were highly correlated with its structural properties. The data reveal the great potential of producing low-cost, high-quality pectins with increased gelling capacity and a broadened scope of applications, by adding a simple HPP pretreatment of fresh source material for pectin extraction.