Wheat straw hemicellulose films as affected by citric acid

Abstract

a b s t r a c tHemicelluloses have been extracted from wheat straw with an alkaline peroxide solution. Biodegradable films intended for food packaging have been produced from hemicelluloses mixed with glycerol and different concentrations of citric acid (as a crosslinking agent), with or without sodium hypophosphite (catalyst to the crosslinking reaction). A curing treatment at 150 C has been carried out on the dried films in order to promote formation of ester bonds between citric acid and hemicelluloses. The crosslinking reaction, evidenced by FTIR spectra, improved water resistance and water vapor barrier properties of the films. On the other hand, the citric acid effects on film tensile properties were more consistent with those of a plasticizer than of a crosslinker, which might be ascribed to a flexible crosslinking. Sodium hypophosphite (SHP) did not affect the properties of crosslinked films. FTIR spectra indicated that some crosslinking reaction occurred even in a non-cured film.

Physical-Chemical Properties of Edible Film Made from Soybean Residue and Citric Acid

“…With the huge development in film processing, the films made of carrot fiber and commercially low methoxyl pectin were developed, and the effect of different sizes on the performance of composite films was explored [2]. Wheat straw hemicellulose films had been mixed with glycerol and different concentrations of citric acid [3]. Due to the large amount of production and relatively low market values of soybean fiber besides its rich residues, it has a great potential as a raw material for preparing films.…”

“…Citric acid can be used as a cross-linking agent in the production of polysaccharide films [9][10][11][12]. e mechanism of cross-linking was that the hydroxyl groups of the polysaccharide and the two carboxyl groups of the citric are cross-linked by covalent intermolecular diester linkages [3,12]. During the crosslinking reaction, high temperature and use of catalyst are very important conditions, where the reaction temperature should be always above 100°C and the catalyst used should be sodium hypophosphite (SHP) [10,12].…”

Biosafe, Eco‐Friendly Levan Polysaccharide toward Transient Electronics

“…Strong peaks for both tested materials near 1010 cm −1 present vibration of the ether functional group (COC), and higher intensity for H‐ M w indicates longer linear chains of polymeric carbohydrates that lead to slower dissolution rates in DI water, in comparison with lower intensity for L‐ M w . The other peaks for vibrations of CH 2 and CH 3 at the region of respective 930 and 1120 cm −1 also play a role in water resistance (Figure d) . It is obvious that the solubility of levan films can be tuned by adjusting the molecular weights.…”

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

“…Ren et al, 72 Kisonen et al 73 ). Recently, Azeredo et al 74 explored the use of wheat straw hemicelluloses in the production of films and barriers using citric acid as a cross-linking agent. In that study, the hemicelluloses were extracted by sequential extraction in alkaline peroxide and recovered by precipitation in ethanol.…”