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Advisor(s)
Abstract(s)
FucoPol is an acylated polysaccharide with demonstrated valuable functional properties
that include a shear thinning fluid behaviour, a film-forming capacity, and an emulsion forming
and stabilizing capacity. In this study, the different conditions (concentration, temperature, and
time) for alkaline treatment were investigated to deacylate FucoPol. Complete deacetylation and
desuccinylation was achieved with 0.02 M NaOH, at 60 ºC for 15 min, with no significant impact on
the biopolymer’s sugar composition, pyruvate content, and molecular mass distribution. FucoPol
depyruvylation by acid hydrolysis was attempted, but it resulted in a very low polymer recovery. The
effect of the ionic strength, pH, and temperature on the deacetylated/desuccinylated polysaccharide,
d-FucoPol, was evaluated, as well as its emulsion and film-forming capacity. d-FucoPol aqueous
solutions maintained the shear thinning behaviour characteristic of FucoPol, but the apparent viscosity
decreased significantly. Moreover, contrary to FucoPol, whose solutions were not affected by the
media’s ionic strength, the d-FucoPol solutions had a significantly higher apparent viscosity for
a higher ionic strength. On the other hand, the d-FucoPol solutions were not affected by the pH
in the range of 3.6–11.5, while FucoPol had a decreased viscosity for acidic pH values and for a
pH above 10.5. Although d-FucoPol displayed an emulsification activity for olive oil similar to
that of FucoPol (98 +- 0%) for an oil-to-water ratio of 2:3, the emulsions were less viscous. The
d-FucoPol films were flexible, with a higher Young0s modulus (798 +- 152 MPa), a stress at the
break (22.5 +- 2.5 MPa), and an elongation at the break (9.3 +- 0.7%) than FucoPol (458 +- 32 MPa,
15.5 +- 0.3 MPa and 8.1 +- 1.0%, respectively). Given these findings, d-FucoPol arises as a promising
novel biopolymer, with distinctive properties that may render it useful for utilization as a suspending
or emulsifier agent, and as a barrier in coatings and packaging films
Description
Keywords
deacetylation desuccinylation alkaline treatment polysaccharide FucoPol rheology emulsion film forming
Pedagogical Context
Citation
Baptista, S.; Araújo, D.; Concórdio-Reis, P.; Marques, A.C.; Fortunato, E.; Alves, V.D.; Freitas, F. Deacetylation and Desuccinylation of the Fucose-Rich Polysaccharide Fucopol: Impact on Biopolymer Physical and Chemical Properties. Molecules 2022, 27, 7165
Publisher
MDPI