Physicochemical and rheological characteristics of pectin extracted from renewable orange peel employing conventional and green technologies. (November 2022)

• Record Type: Journal Article
• Authors: Zioga, Marianthi; Tsouko, Erminta; Maina, Sofia; Koutinas, Apostolis; Mandala, Ioanna; Evageliou, Vasiliki
• Is Part Of: Food hydrocolloids. Volume 132(2022)
• Publication Date: 2022-11
• Subjects: Pectin -- Acidic and microwave assisted extraction -- Orange peel waste -- Gels -- Emulsions; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2022.107887
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: Hydrochloric acid- (HAE), citric acid- (CAE) and microwave-assisted extraction (MAE) of pectins from orange peels, as a whole or their albedos, was performed. Pectin yield varied from 10.6 to 22.8%, galacturonic acid content (GalA) from 46 to 73.5%, intrinsic viscosity [η] from 0.3 to 0.8 dL/g and molecular weight from 5 to 15 kDa. All pectins were high methoxy pectins with a degree of esterification (DE) > 50% and their solutions presented acidic pH values. The studied properties were affected by both extraction conditions and raw material. The gelling and emulsifying properties of the pectins were also evaluated. HAE pectin-based emulsions were more stable and showed greater viscosity and lower conductivity. All pectins formed a gel network on cooling from 95 °C to 5 °C, which was thermally irreversible with the exception of CAE pectins that presented an increase of moduli at temperatures >40 °C. A thermal annealing behaviour was observed when gels were taken to high temperature and re-cooled. All gels exhibited great syneresis. Overall, the extracted pectins can be good candidates for the formation of food products of specific textural and rheological properties. Graphical abstract: Image 1 Highlights: Pectin extracted from orange peel using conventional and green technologies. Extraction conditions and raw material affected properties and yield. Microwave extracted pectins showed good yields, high GalA and DE values. HCl pectins gave more stable emulsions with greater viscosity & lower conductivity. Thermal annealing observed when gels were taken to high temperature and re-cooled.