174 Novel food packaging techniques Cao Molecular sieve Casos Fig 9.1 Adsorption isotherms@ 25C Regeneration of packaged silica gel may be limited by the temperature tolerance of the package material itself. 9.2.6 Packaging and applications Silica gel, as with other desiccants, is often packed in pouches or sachets Materials range from adhesive coated papers and paper based laminates to non- wovens(coated and uncoated)to permeable or microperforated films. Semi rigid capsules of many constructions are available with varying degrees of porosity and permeability. Occasionally, silica gel is filled into injection. moulded packages or incorporated directly into resins for moulding or extrusion. The uses of silica gel are too numerous to list. They include foodstuffs, pharmaceuticals, medical and diagnostic devices, textiles, leather goods, sealed electronics and many more 9.3 Cla 9.3. 1 Nomenclature and sourees Nearly all sources and types of clay, when fully dried, have some adsorptive properties. Clays used commercially fall into the category of Bentonite. The most frequently used is Montmorillonite. Clays are principally composed of metal silicates with some sulfates and phosphates present.Regeneration of packaged silica gel may be limited by the temperature tolerance of the package material itself. 9.2.6 Packaging and applications Silica gel, as with other desiccants, is often packed in pouches or sachets. Materials range from adhesive coated papers and paper based laminates to non￾wovens (coated and uncoated) to permeable or microperforated films. Semi￾rigid capsules of many constructions are available with varying degrees of porosity and permeability. Occasionally, silica gel is filled into injection￾moulded packages or incorporated directly into resins for moulding or extrusion. The uses of silica gel are too numerous to list. They include foodstuffs, pharmaceuticals, medical and diagnostic devices, textiles, leather goods, sealed electronics and many more. 9.3 Clay 9.3.1 Nomenclature and sources Nearly all sources and types of clay, when fully dried, have some adsorptive properties. Clays used commercially fall into the category of Bentonite. The most frequently used is Montmorillonite. Clays are principally composed of metal silicates with some sulfates and phosphates present. Fig. 9.1 Adsorption isotherms @ 25ºC. 174 Novel food packaging techniques