Zeta
potential
and
particle
size
were
determined
on
pectin
aqueous
solutions
as
a
function
of
pH
and
the
effects
of
calcium
ions,
putrescine
and
spermidine
on
pectin
film
forming
solutions
and
derived
films
were
studied.
Ca2+ and
polyamines
were
found
to
differently
influence
pectin
zeta
potential
as
well
as
thickness
and
mechanical
and
barrier
properties
of
pectin
films
prepared
at
pH
7.5
either
in
the
presence
or
absence
of
the
plasticizer
glycerol.
In
particular,
Ca2+ was
found
to
increase
film
tensile
strength
and
elongation
at
break
only
in
the
presence
of
glycerol
and
did
not
affect
film
thickness
and
permeability
to
both
water
vapor
and
CO2.
Conversely,
increasing
polyamine
concentrations
progressively
reduced
film
tensile
strength
and
markedly
enhanced
film
thickness,
elongation
at
break
and
permeability
to
water
vapor
and
CO2,
both
in
the
presence
and
absence
of
glycerol.
Our
findings
indicate
that
polyamines
give
rise
to
a
structural
organization
of
the
heteropolysaccharide different from that determined by calcium ions, previously described as “egg box” model, and suggest their possible application as plasticizers to produce pectin-based “bioplastics” with different features.