PHYSICAL AND MECHANICAL-PROPERTIES OF HIGHLY PLASTICIZED PECTIN STARCH FILMS

Blends of citrus pectin and high amylose starch plasticized with glyce rine were investigated to determine the effect of compositional variab les on film properties. Several films with representative compositions were made from sugar beet and almond pectin, and tested for compariso n. The films were cast from water onto glass plates, dried, and remove d. Mechanical analysis was done using a Rheometrics RSA II solids anal yzer. Increasing the glycerine concentration led to decreases in stati c modulus, dynamic modulus, and tensile strength, but to increases in elongation. Increasing levels of starch in the blend lowered the effec t of glycerine on mechanical properties. Oxygen permeability of the fi lms was extremely low. Sugar-beet pectin and almond pectin gave films with mechanical properties comparable to those made with citrus pectin . (C) 1994 John Wiley & Sons, Inc.