Figure 1.

Preparation of pectin polymers. (A) Powered pectin with low methyl esterification (less than 50%) was prepared in a high-shear mixer and poured into a mold for curing and subsequent analysis. (B) After curing to a 10% water content, the low-methoxyl pectin (LMP) films were grossly transparent. (C) With the addition of calcium, microscopic examination demonstrated an increased number of microaggregates with an increasing calcium concentration (Bar = 250 µm). When compared to pectin films with high methyl esterification, the thickness of the LMP was similar to high-methoxyl pectin (HMP) at a range of water contents (LMP R² = 0.855; HMP R² = 0.949) (D). The addition of 10 mM calcium to the LMP resulted in a slightly thicker film than the HMP film at a water content of 30 ± 2% (w/w) (p < 0.05) (E). Error bars = 1 SD.