title: Oxygen permeability of films made from CO2-precipitated casein and modified casein.
abstract: Oxygen permeabilities (OP) of CO(2)-casein (CO(2)CN), calcium caseinate (CaCN), and acylated casein (AcCN) films were determined as functions of % relative humidity (% RH), temperature, and plasticizer type. Tensile properties and water vapor permeabilities (WVP) were also measured. Plasticizers were glycerol (GLY) or a 3:1 ratio of GLY:poly(propylene glycol) (PPG), a hydrophobic plasticizer. OP of the CO(2)CN:GLY film was almost twice that of films containing either plasticizer at 35% RH, but its OP approached that of the other films at 70% RH. OP and WVP of films plasticized with GLY were greater than that for films plasticized with PPG. Plasticizer type had little impact on the tensile strength of CO(2)CN films while tensile strength of CaCN-GLY:PPG (3:1) films approximately doubled. Results show that structural dissimilarities in the films contribute to differences in OP only under conditions of low RH where the plasticizing effects of water are not significant.
authors.affiliation: Dairy Processing and Products Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA. ptomasula@arserrc.gov
authors.forename: Peggy M
authors.initials: PM
authors.lastname: Tomasula
authors.forename: Winnie C
authors.initials: WC
authors.lastname: Yee
authors.forename: Nicholas
authors.initials: N
authors.lastname: Parris
mesh_terms: D000215:Acylation; D002245:Carbon Dioxide / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry*; D011232:Chemical Precipitation; D018857:Food Packaging; D005990:Glycerol; D006813:Humidity; D010100:Oxygen / Q000737:chemistry*; D010539:Permeability; D010968:Plasticizers; D011108:Polymers; D011409:Propylene Glycols; D013696:Temperature; D013718:Tensile Strength
chemical_list: D002364:Caseins; D010968:Plasticizers; D011108:Polymers; D011409:Propylene Glycols; D002245:Carbon Dioxide; C012504:polypropylene glycol; D005990:Glycerol; D010100:Oxygen