Comparative study of the mechanical properties of edible filmsmade from single and blended hydrophilic biopolymer matrices

Sodium alginate, κ-carrageenan, mesquite gum and/or whey protein concentrate were used alone or blended for obtaining edible films, using sorbitol as plasticizer. Film mechanical properties were determined with a TA-XT2 texture analyzer. Films with greater breaking factor, tensile strength, tensile strength at break, and tensile energy at break were obtained when sodium alginate was used alone. Low Young's modulus values were obtained with blends of sodium alginate and κ-carrageenan (with the latter predominating in the blend) and mesquite gum-whey protein concentrate (with the former predominating in the blend). The latter blend exhibited highest elongation. Films containing pure sodium alginate or κ-carrageenan or blended with the other gums (with sodium alginate predominating) could be classified as hard, strong and resistant. Films where mesquite gum or whey protein concentrates were on their or where their blend predominated over that of sodium alginate and/or κ-carragenan were mostly soft and weak.