Two stage extrusion of plasticized pectin/poly(vinyl alcohol) blends

AGFD 82

Marshall L. Fishman, mfishman@errc.ars.usda.gov1, David R. Coffin, dcoffin@errc.ars.usda.gov1, Charles I. Onwulata, conwulata@errc.ars.usda.gov2, and J. L. Willett3. (1) Crop Conversion Science and Engineering, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, (2) Dairy Processing and Products, U.S. Deparment of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, (3) Plant Polymer Research, U.S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 N. University Street, Peoria, IL 61604
Blends of pectin with starch (high amylose and normal), poly(vinyl alcohol) (PVOH), and glycerol were extruded in a twin screw extruder, pelletized, and then further processed into blown films and extruded sheets using a single screw extruder. The samples were analyzed using tensile measurements, dynamic mechanical analysis, and scanning electron microscopy (SEM). PVOH levels of 24% or greater were necessary to successfully make blown films, while extruded sheet could be made at a level of 16% PVOH. For purposes of comparison the mechanical properties of films made by solution casting also were measured. Increased levels of PVOH led to increases in tensile strength and elongation to break, while initial modulus was decreased. Morphology as determined by SEM visually indicated stretching in the transverse direction of the blown films. The second stage extrusion appeared to promote alpha-helix formation in the high amylose starch.
 

General Posters
1:00 PM-3:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Agricultural & Food Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006