STERIC EXCLUSION PHENOMENA IN GELLAN GELATIN SYSTEMS .1. PHYSICAL-PROPERTIES OF SINGLE AND BINARY GELS

The scientific and technological aspects of gellan/gelatin systems wer e investigated under conditions of low pH and in the presence of a wid e range of cations so that the normally important electrostatic intera ctions between the two polymers should be suppressed. The structural a nd textural characteristics of mixed gels were monitored using the tec hniques of mechanical spectroscopy, differential scanning calorimetry and compression testing. Under such conditions where positive interact ions between the two components would be minimized. it was found that results could be described on the basis of thermodynamically incompati ble polymers which gel independently in their respective phases. Intel ligent manipulation of polymer concentration and ionic strength promot es phase inversion from a gellan continuous phase to a system where ge latin forms the supporting matrix. The knowledge gained in this study might assist in developing food products with novel textures.