Adding corn fiber to the trays lowers their mechanical properties. The force needed to break the trays decreased from 75 N for trays containing no corn fiber to less than 20 N for trays containing 54.7% corn fiber (Fig. 6a). The added fiber is acting as a nonreinforcing filler and as such is diluting the starch in the tray, which is the load bearing material. The shape of the added corn fiber, which is mostly spherical in nature, does not add any reinforcement. For corn fiber to be an effective filler, it needs to have a more elongated structure. Aspen fiber with a high aspect ratio has been shown to improve the strength of baked starch foams when added in concentrations up to 30% [26] and [27]. The addition of the high molecular weight PVA (PH) mitigates the decrease in tray strength associated with the addition of fiber (Fig. 6a). Trays made with PVA-PH and up to 48% corn fiber have tray strengths approximately the same as trays made with only potato starch. The lower molecular weight PVA (PL) did not perform as well. When the weight of the tray was taken into account the PVA-PL samples performed worse than trays containing no PVA-PL (Fig. 6b). When the strength of the tray was calculated in Newtons per gram, the ability of high molecular weight PVA to improve tray strength is confirmed. However, when corn fiber is added trays performed statistically no better than trays without PVA.