Characterization of Pectin from Grape Pomace: A Comparison of Conventional and Pulsed Ultrasound-Assisted Extraction Techniques

• Published in: Foods 2022-07, Vol.11 (15), p.2274
• Main Authors: Spinei, Mariana, Oroian, Mircea
• Format: Article
• Language: English
• Subjects: Agricultural wastes; Amplitudes; Caustic soda; characterization; Chemical properties; comparison; Composition; Esterification; Food science; grape pomace; Grapes; Green chemistry; Identification and classification; Independent variables; Infrared spectroscopy; Molecular weight; Natural resources; Parameters; Pectin; pH effects; Physicochemical properties; Polysaccharides; Rheological properties; Rheology; Ultrasonic imaging; Ultrasonic testing; Ultrasound; Viscoelasticity; Viscosity; Waste management
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods11152274

The yield, physicochemical and rheological parameters of grape pomace pectin (Fetească Neagră and Rară Neagră) obtained by conventional extraction (CE) were compared to those acquired by pulsed ultrasound-assisted extraction (PUAE). Extraction temperature (70–90 °C), pH (1–3) and time (1–3 h) were considered as independent variables for CE, while amplitude (20–100%), pH (1–3) and time (20–60 min) for PUAE. The optimal conditions for maximum yield and physicochemical parameters of pectin samples extracted by CE were temperature of 90 °C, pH 1.9 for 164 min (9.96% yield, 79.91 g/100 g of galacturonic acid (GalA) content, 81.28% of degree of esterification (DE) and 5.52 × 104 g/mol of molecular weight (Mw) for Fetească Neagră (FN) pectin; 11.08% yield, 80.05 g/100 g of GalA content, 80.86% of DE and 5.59 × 104 g/mol of Mw for Rară Neagră (RN) pectin), while for PUAE they were amplitude of 100%, pH 1.8 for 60 min (8.83% yield, 80.24 g/100 g of GalA content, 81.07% of DE and 4.19 × 104 g/mol of Mw for FN pectin; 8.94% yield, 78.64 g/100 g of GalA content, 80.04% of DE and 4.23 × 104 g/mol of Mw for RN pectin). The yield and physicochemical parameters of CE pectin were higher than PUAE pectin. The FT-IR spectra of pectin samples revealed the occurrence of polysaccharide compound, while rheology characteristics confirming its application in different food products.