Introduction

EDIBLE films and coatings can increase food product shelf life and improvefood quality by acting as barriers to control the transfer of moisture, gases, lipids, and aroma compounds. Properties and potential uses of edible films and coatings based on polysaccharides, lipids, and proteins have been reviewed (Guilbert, 1986; Kester and Fennema, 1986; Krochta, 1992). Several proteins have been used to produce films including collagen, gelatin, casein, whey proteins, corn zein, wheat gluten, soy protein, and peanut protein. In general, protein films are excellent barriers to the transport of gases but moderate barriers to the transport of moisture (Krochta, 1992). Their water vapor barrier ability is limited by the inherent hydrophilic nature of proteins. However, protein films, when dry, transmit oxygen and carbon dioxide at low levels (Gennadios et al., 1993; McHugh and Krochta, 1994a; Gontard et al., 1996; Mujica-Paz and Gontard, 1997).