Cryogelation of alginate improved the freeze-thaw stability of oil-in-water emulsions

Cryogelation of polysaccharide was hypothesized as a novel way to improve the freeze-thaw (FT) stability of emulsion. This hypothesis was tested using a cryogelling polysaccharide - alginate. In the absence of alginate, emulsions stabilized with Tween 20 and sugar esters were not stable against FT treatment. In the presence of alginate, improved stability of emulsions, i.e. less oiling-off was observed after FT treatment at pH 5.0 where cryogelation was not occurred. However, significant improved stability, i.e. complete retarding of creaming, no oiling-off, and smaller emulsion droplet sizes were observed at pH 3.5 and 3.0 where cryogelation was occurred. The improved FT stability was associated with the increased emulsions moduli due to cryogelation. The rheological properties of original emulsions were largely recovered by a heating processing at 35 degrees C for 2 h. Our results indicated that cryogelation of biopolymers could be used to improve the FT stability of emulsions.