title: Extraction of agar from Gelidium sesquipedale (Rhodopyta) and surface characterization of agar based films.
abstract: The chemical structure of the agar obtained from Gelidium sesquipedale (Rhodophyta) has been determined by (13)C nuclear magnetic resonance ((13)C NMR) and Fourier transform infrared spectroscopy (FTIR). Agar (AG) films with different amounts of soy protein isolate (SPI) were prepared using a thermo-moulding method, and transparent and hydrophobic films were obtained and characterized. FTIR analysis provided a detailed description of the binding groups present in the films, such as carboxylic, hydroxyl and sulfonate groups, while the surface composition was examined using X-ray photoelectron spectroscopy (XPS). The changes observed by FTIR and XPS spectra suggested interactions between functional groups of agar and SPI. This is a novel approach to the characterization of agar-based films and provides knowledge about the compatibility of agar and soy protein for further investigation of the functional properties of biodegradable films based on these biopolymers.
authors.affiliation: BIOMAT Research Group, University of the Basque Country (UPV/EHU), Polytechnic School, Donostia-San Sebastián, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Guerrero
authors.forename: A
authors.initials: A
authors.lastname: Etxabide
authors.forename: I
authors.initials: I
authors.lastname: Leceta
authors.forename: M
authors.initials: M
authors.lastname: Peñalba
authors.forename: K
authors.initials: K
authors.lastname: de la Caba
mesh_terms: D000362:Agar / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D001672:Biocompatible Materials / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008855:Microscopy, Electron, Scanning; D056951:Photoelectron Spectroscopy; D000461:Rhodophyta / Q000737:chemistry*; D030262:Soybean Proteins / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D030262:Soybean Proteins; D000362:Agar
keywords: (13)C NMR; Agar; FTIR; Films; Gelidium; SPI; Thermo-moulding; XPS