Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2007
Publication Date: July 28, 2007
Citation: Dangaran, K.L., Cooke, P.H., Tomasula, P.M. 2007. Blended films of novel casein with four different carrageenans to improve properties. IFT Meeting Abstract. Technical Abstract: A novel CO2-precipitated casein (CO2CAS) forms films that are excellent oxygen barriers and moderate moisture barriers. CO2CAS films are strong, but elongation needs improvement. Blending biopolymers can improve properties of films. It is known that different types of carrageenans (kappa, iota, and lambda) have different microstructure, gel properties and adsorb to casein micelles. The interactions between carrageenans and CO2CAS have not been previously studied in films, and we hypothesized that each carrageenan type would affect the tensile properties of casein films differently. The objective of this study was to determine tensile, moisture barrier and structural properties of blended films made from CO2CAS and different carrageenans. Films were made from CO2CAS and carrageenan - kappa (2), iota, or lambda. The protein:carbohydrate ratio was 1:1 in the blended films, and all films were plasticized with glycerol (20%). Tensile properties and water vapor permeability (WVP) were measured following ASTM methodology. Thermal scans of the films were performed with DSC. The microstructure of the films was studied with confocal microscopy and SEM. All blended films had WVP slightly higher than CO2CAS films, but the difference was statistically insignificant. The strength of CO2CAS films was increased from 13.2 MPa to 22.4-23.3 MPa with the addition of kappa-carrageenan. Elongation was significantly increased from 5.6% to 42.9% with lambda-carrageenan. Thermal scans of the blended films showed one melting peak. Microscopic analysis showed differences among the blended films with the iota- or kappa-carrageenan-containing films having striated cross-sections within the film microstructure. CO2CAS films have the potential to be high performance packaging layers. All carrageenans had a significant effect on the tensile properties of CO2CAS films; however, it is concluded that lambda-carrageenan is best to use because it improves the elongation and resiliency of casein films with insignificant effects to the moisture barrier properties.