Flexible oxygen barrier films from spruce xylan

• Arabinoglucuronoxylan was extracted from Norway spruce and films prepared by casting from aqueous solution. The sugar analysis and NMR confirmed that the spruce xylan was composed of arabinose, 4-O-methyl-glucuronic acid and xylose in a ratio of 1:2:11 respectively. Substitutions of 4-O-methyl-alpha-D-GlcpA at O-2 and of alpha-L-Araf at O-3 on the xylose backbone were found by NOE analysis. NOE cross-peaks indicated as well that there is at least one free xylose on the main chain present between two substitutions. Whether the distribution of side chains was random or in blocks was uncertain. The average molecular weight of the sample was determined by size exclusion chromatography to be 12,780 g/mol. Arabinoglucoronoxylan casting yielded transparent flexible films with an average stress at break of 55 MPa, strain at break of 2.7% and a Young's Modulus 2735 MPa. Wide-angle X-ray scattering analysis showed that the arabinoglucuronoxylan films were totally amorphous. Addition of sorbitol as plasticizer resulted in less strong but more flexible films (strain at break of 5%). Peaks of crystallinity could be seen in X-ray which corresponds to sorbitol crystallizing in distinct phases. The dynamic mechanical analysis showed that the arabinoglucuronoxylan film softened at a later relative humidity (80% RH) in comparison with plasticized films (60% RH). The films showed low oxygen permeability and thus have a potential application in food packaging.

Ämnesord

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

LANTBRUKSVETENSKAPER  -- Annan lantbruksvetenskap -- Förnyelsebar bioenergi (hsv//swe)

AGRICULTURAL SCIENCES  -- Other Agricultural Sciences -- Renewable Bioenergy Research (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Polymerteknologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Polymer Technologies (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Trävetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Wood Science (hsv//eng)

Nyckelord

dietary fiber

wood

Material

Arabinoglucuronoxylan

barley

spectroscopy

properties

Film formation

oligosaccharides

Characterization

arabinoxylans

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)