Properties of cysteine-added say protein-wheat gluten films

Soy and wheat proteins as film ingredients are advantageous due to relative abundance, biodegradability, and their renewable nature. Research objectiv es were to evaluate effectiveness of gluten and cysteine addition in improv ing properties of soy protein-based films. Thickness, mechanical, and barri er properties were evaluated. Gluten addition and pH 3.0 lowered water vapo r permeability and thickness. Mechanical properties were enhanced at pH 7.0 with cysteine addition. Cysteine increased tensile strength of some treatm ents due to increase In disulfide bond formation. Best compromise between b arrier and mechanical properties was observed for the cysteine-added soy:gl uten (4:1) film at pH 7.0. These films could find application as primary pa ckaging for low moisture foods.