title: Ultrasound assisted extraction and characterization of pectin from tomato waste.
abstract: Pectin was extracted from tomato waste using two different extraction methods to assess its potential utilization as an alternative source of commercial pectin production. Tomato waste was treated with ammonium oxalate/oxalic acid by conventional extraction (CE), under reflux and ultrasound assisted extraction (UAE) at 37 kHz and temperatures of 60 °C and 80 °C. The pectin obtained from these methods was analysed and compared in terms of yield, chemical properties and structure. Among examined methods, CE at 60 °C resulted with the highest yield, but UAE during 15 min of sonication produced the pectin of better quality (anhydrouronic acid, methoxy and calcium pectate contents and degree of esterification). NMR and FTIR spectroscopy of isolated pectins revealed predominantly esterified structure, irrespective of extraction conditions. The comparison of the pectin yields obtained after extraction at 80 °C, indicate that similar values were found at times of 24h and 15 min for CE and UAE, respectively. According to obtained results it can be concluded that main advantage of UAE is considerable shortening of extraction procedure with strong emphasis on environmental friendly processing approach. Therefore, these results suggested that UAE could be used as an efficient technique for the extraction of pectin from tomato waste and by-products.
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia. Electronic address: aninc@pbf.hr.
authors.forename: Antonela Ninčević
authors.initials: AN
authors.lastname: Grassino
authors.affiliation: Department of Process Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia. Electronic address: mbrncic@pbf.hr.
authors.forename: Mladen
authors.initials: M
authors.lastname: Brnčić
authors.affiliation: NMR Centre, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
authors.forename: Dražen
authors.initials: D
authors.lastname: Vikić-Topić
authors.affiliation: NMR Centre, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
authors.forename: Sunčica
authors.initials: S
authors.lastname: Roca
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Maja
authors.initials: M
authors.lastname: Dent
authors.affiliation: Department of Food Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Suzana Rimac
authors.initials: SR
authors.lastname: Brnčić
mesh_terms: D018551:Solanum lycopersicum / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010368:Pectins / Q000737:chemistry*; D013010:Sonication / Q000379:methods*; D014465:Ultrasonics / Q000379:methods*
chemical_list: D010368:Pectins
keywords: Conventional extraction; NMR and IR spectroscopy; Pectin; Sonication; Tomato waste