Plasticizing-Antiplasticizing Effects of Water on Physical Properties of Tapioca Starch Films in the Glassy State

The effects of moisture sorption on physical properties of native and cross-linked starch films in the glassy state were studied. Water played a dual role as a plasticizer or an antiplasticizer, depending on the physical property measured. Plasticizing effects were clearly evident in the case of the calorimetric glass transition tempera- ture (T g ), tensile modulus, linear expansion, and water vapor permeability. In contrast, antiplasticization by water resulted in maxima in tensile strength, strain-at-break, and toughness of films that were observed at an intermedi- ate moisture content ranging from 4% to 8% (RVP 0.1 to 0.4). The seemingly contradictory effects of water on me- chanical properties associated with lower and higher deformation of starch films were reconciled by assigning dif- ferent roles to water operating primarily via opposite entropic/free volume effects. Relationships, if any, between

[1]  Y. P. Chang,et al.  Antiplasticization by Water in Reduced-Moisture Food Systems , 1999 .

[2]  A. Darke,et al.  Thermal properties of polysaccharides at low moisture: Part 3 — Comparative behaviour of guar gum and dextran , 1998 .

[3]  G. Padua,et al.  Water Vapor Barrier Properties of Zein Films Plasticized with Oleic Acid , 1998 .

[4]  G. Padua,et al.  Properties and Microstructure of Zein Sheets Plasticized with Palmitic and Stearic Acids , 1997 .

[5]  M. Gidley,et al.  Thermal properties of polysaccharides at low moisture , 1996 .

[6]  T. Vliet,et al.  Recrystallization of amylopectin in concentrated starch gels. , 1996 .

[7]  Micha Peleg,et al.  Patterns of textural changes in brittle cellular cereal foods caused by moisture sorption , 1996 .

[8]  J. Delcour,et al.  Pasting Profiles and Solubility of Native and Cross-Linked Corn Starch inDimethylsulfoxide-Water Mixtures , 1995 .

[9]  N. Parris,et al.  Composition factors affecting the water vapor permeability and tensile properties of hydrophilic zein films , 1995 .

[10]  E. Grulke,et al.  A Model for Antiplasticization in Polystyrene , 1995 .

[11]  P. J. Lillford,et al.  Glass transitions and the fracture behaviour of gluten and starches within the glassy state , 1995 .

[12]  F. Debeaufort,et al.  Water vapor permeability and diffusivity through methylcellulose edible films , 1994 .

[13]  D. Göritz,et al.  Investigations on high amylose corn starch films. Part 2: Water vapor sorption , 1994 .

[14]  M. Gidley,et al.  Thermal properties of polysaccharides at low moisture: 1—An endothermic melting process and water-carbohydrate interactions , 1993 .

[15]  N. Gontard,et al.  Water and Glycerol as Plasticizers Affect Mechanical and Water Vapor Barrier Properties of an Edible Wheat Gluten Film , 1993 .

[16]  J. Jane,et al.  澱粉粒中のアミロースの所在 I アミロースとアミロペクチンの架橋結合試薬への感受性 , 1992 .

[17]  J. Jane,et al.  Location of amylose in normal starch granules. I. Susceptibility of amylose and amylopectin to cross-linking reagents , 1992 .

[18]  S. Ablett,et al.  The glass transition of amylopectin measured by DSC, DMTA and NMR , 1992 .

[19]  R. Shogren.  Effect of moisture content on the melting and subsequent physical aging of cornstarch , 1992 .

[20]  L. Slade,et al.  Beyond water activity: recent advances based on an alternative approach to the assessment of food quality and safety. , 1991, Critical reviews in food science and nutrition.

[21]  L. Slade,et al.  Water Science Reviews 3: Water as a plasticizer: physico-chemical aspects of low-moisture polymeric systems , 1988 .

[22]  J. S. Vrentas,et al.  Antiplasticization and volumetric behavior in glassy polymers , 1988 .

[23]  P. K. Hari,et al.  Some Studies on Modified Starch for Low Humidity Application , 1986 .

[24]  L. Greenspan.  Humidity Fixed Points of Binary Saturated Aqueous Solutions , 1977, Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry.

[25]  G. S. Banker.  Film coating theory and practice. , 1966, Journal of pharmaceutical sciences.