Single-use food containers with a self-closing hinged lid made of extruded polystyrene (EPS) or coated paperboard
(PB) are used to serve a variety of food products. Food containers made of materials that are inexpensive and can
be composted into a useful mulch would be of commercial interest as a replacement for EPS or PB. In this report,
a baking process was used to study the functional properties of foams made of starch or starch composites containing
fiber and/or CaCO3. Baked foams made of formulations containing only starch had a lower flexural strain to break
(eb) and elongation to break (Elmax) than EPS or PB foams. The eb was increased by lowering the starch
concentration in the formulations, using potato starch versus wheat, corn or tapioca starch and by increasing the
moisture content. Nevertheless, the eb and Elmax values remained lower than in the EPS and PB samples. Calcium
carbonate did not improve the mechanical properties of the foams. Foams containing starch and CaCO3 were more
dense with lower eb and Elmax compared to foams containing only starch. Foam density decreased and eb markedly
increased by including softwood fiber in the dough formulations. Formulations with a starch/fiber ratio of
approximately 5:1 or less made baked foams with eb values greater than 5% and Elmax values nearly double those
of foams containing only starch. The addition of CaCO3 to starch/fiber foam composites did not improve foam
properties. The CaCO3 increased density and decreased eb and Elmax values compared to foams made of starch and
fiber. Published by Elsevier Science B.V.