Pectin-based biodegradable water insoluble films

Aqueous solutions of pectin, an acidic polysaccharide which occurs in various natural products, was cast into clear films. While the films were flexible enough to be used as wrapping materials, their strength and resistance to water were inferior to presently used commercial films. However, precast films immersed into aqueous solutions of multivalent cations became insoluble in water and depending on the ions became stronger in tension. Tensile strength increased to levels comparable to, or in the case of calcium, copper(II) and zinc, greater than those of some commercial wrapping materials.