Structural, functional and physicochemical properties of pectin from grape pomace as affected by different extraction techniques

Abstract

Pectin from grape pomace (Vitis vinifera var. Fetească Neagră and Vitis vinifera var. Rară Neagră) was extracted by using different extraction techniques (conventional, microwave-assisted and pulsed ultrasound-assisted extraction). Microwave-assisted extraction showed highest yield (11.2 %) for Rară Neagră pectin, while conventional extraction presented highest yield (9.9 %) for Fetească Neagră pectin. The yield was directly correlated with the galacturonic acid content, degree of esterification, molecular weight and functional features (water-holding, oil-holding and water-swelling capacity, emulsifying properties and rheological behavior of pectin emulsions). In addition, the FT-IR, morphological structure, thermal analysis and emulsion properties of obtained pectin samples from different extraction techniques revealed dissimilar results by comparing with commercial pectin.