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

Authors: Zhao, Wei; Xu, Yixiang; Dorado, Christina; Bai, Jinhe; Chau, Hoa - Rose; Hotchkiss, Arland; Yadav, Madhav; Cameron, Randall - Randy

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2023
Publication Date: 11/11/2023
Citation: Zhao, W., Xu, Y., Dorado, C., Bai, J., Chau, H.K., Hotchkiss, A.T., Yadav, M.P., Cameron, R.G. 2023. 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. Food Hydrocolloids. 149/109536. https://doi.org/10.1016/j.foodhyd.2023.109536.
DOI: https://doi.org/10.1016/j.foodhyd.2023.109536

Interpretive Summary: Pectin is a complex polysaccharide widely used in the food and pharmaceutical industries due to its gelling, thickening, and stabilizing properties. The functionality of pectin is closely related to its structural features. Pectin obtained with commercial extraction method is usually high-methoxyl (HM) and demethylation of pectin is needed to enable the pectin to gel without the requirement of high sugar added. Enzymatic demethylation of pectin with plant pectin methyl-esterase (PME) generates high quality pectin with much higher gelling quality than the pectin generated by chemical demethylation. However, the cost is much higher for treatments by plant PME than by chemicals. In the companion article, the modification of pectin structure in source plant material with high-pressure processing (HPP) was reported. The HPP-modified pectins (Hp) had structural features similar to the effects of enzymatic demethylation of pectin with plant PME. In this study, the functionalities of the Hp were evaluated and compared with commercial low methoxy (LM) and high methoxy (HM) pectins. Results indicate that HPP-pretreatment introduced calcium sensitivity to pectin, remarkably increased Ca2+-mediated gelation capacity of pectin and the quality of Ca2+-gels of Hp was comparable to commercial LM pectin; while Hp still remained the capacity for sugar-acid-mediated gelation. Hp had also higher emulsifying stability than the control and commercial pectins. The results indicate the HPP pretreatment of fresh source material for pectin extraction could be an efficient way to produce high quality pectins with increased gelling capacity and a broadened scope of applications as well as a low cost.

Technical Abstract: The most important functionalities for pectin to be used in foods 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. Modification of pectin with high-pressure processing treatment of fresh orange peel before pectin extraction: Part I. The effects on pectin extraction and physicochemical and structural properties. Food Hydrocolloids], 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 results of calcium sensitivity test and rheological analyses showed that 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. The results of emulsifying tests showed Hp had higher emulsifying stability than the control and commercial pectins. The increased capacity of Hp for calcium-mediated gelation was attributed to the increase in degree of blockiness of non-esterified galacturonic acid, 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 high quality pectins with increased gelling capacity and a broadened scope of applications as well as a low cost, by adding a simple HPP pretreatment of fresh source material for pectin extraction.