Effect of ozonation on the rheological and colour characteristics of hydrocolloid dispersions

The effect of ozonation on the theological and colour characteristics of guar, carboxyl methyl cellulose (CMC), and pectin dispersions was investigated. Guar 1%, CMC 1% and pectin 2% (w/v) dispersions were ozonated at varying ozone concentrations of 2.4%, 4.0%, 5.6% and 7.8% (w/w) for 3, 5, 7 and 10 min processing times at 20 +/- 1.0 degrees C. Flow and dynamic rheological properties together with Hunter colour parameters (L-., a(.), b(.)) were measured for control and treated samples. Significant differences were observed in the rheological characteristics and colour of all ozonated hydrocolloid dispersion studied. No recovery was observed in the structure breakdown after a 24 h storage period. This study indicates that ozonation has a significant effect on both the rheology and colour of hydrocolloid dispersions and that due attention should be given before incorporating these hydrocolloids in food formulations which are subsequently ozonated in food processing and preservation processes. (C) 2008 Elsevier Ltd. All rights reserved.