Figure 1.

Preparation of pectin films. A) Pectin solutions (3–4% w/w) were created by mixing pectin powder in deionized water using a high-shear mixer (see Methods) at room temperature. B) The dispersed solutions were cured in a 20% relative humidity environment with progressive evaporation of water. C) The pectin solutions were tested for evidence of polymerization at various times in the curing process. A load cell, mounted with a cylindrical acrylic probe, was used to identify the initial phase of phase of polymerization. D) The force required to compress the pectin solution to 50% its baseline thickness (black arrow) and withdraw probe (gray arrow) were recorded. E-F) The force required to compress and withdraw the probe were significantly increased at 12 hours.