Fibrous sheets are coated or impregnated with a biodegradable composition to render the sheets more resistant to penetration by liquids. Biodegradable polymer blends suitable for use in coating or impregnating a fibrous sheet can be manufactured from at least one "hard" biodegradable polymer and at least one "soft" biodegradable polymer. "Hard" biopolymers typically have a glass transition temperature of at least about 10.degree. C. "Soft" biodegradable polymers typically have a glass transition temperature less than about 0.degree. C. Another useful biodegradable polymer composition includes one or more biodegradable polymers and sufficient inorganic filler so as to render the treated sheet microwaveable. The biodegradable polymer compositions are especially well-suited for coating or impregnating paper sheets, e.g., 12 15 lb/3000 ft.sup.2 tissue paper to yield food wraps. Food wraps will typically be manufactured to have good "dead-fold" properties so as to remain in a wrapped position and not spring back to an "unwrapped" form.