It was previously reported that the cross-linking of corn starch
with 0.13 g/kg glyoxal considerably reduced the baking time, density
and water absorption properties of corn starch foam trays
(Uslu and Polat, 2012). A small increase in the flexural properties
of the trays due to cross-linking was also reported. For this reason,
glyoxal (0.13 g kg1) cross-linked corn starch was used exclusively
in our study as the starch source.
For the glyoxal treatment, starch (40 g, dry basis) was suspended
in distilled water (60 ml). Glyoxal was added to a level of
0.13 g kg1 (based on the dry weight of the starch) using a micropipette.
The solution containing starch and glyoxal was continuously
stirred (300 rpm) for 24 h at 25 C to ensure homogenisation. The
slurry was then filtered through 20 lm filter paper, and the starch
was washed with distilled water (3 300 ml) and dried at 50 C for
one day. The treated starch was ground with a hammer mill (IKA
Laborte