Improvement in the remaining activity of freeze-dried xanthine oxidase with the addition of a disaccharide-polymer mixture

Srirangsan Paveena

Kawai Kiyoshi

Hamada-Sato Naoko

Watanabe Manabu

Suzuki Toru

Food Chemistry

In order to improve the remaining activity of a practically important freeze-dried enzyme, xanthine oxidase (XOD), the effects of disaccharide (sucrose and trehalose), polymer (bovine serum albumin: BSA and dextran) and a mixture of them on the loss of XOD activity during freeze-drying and subsequent storage were investigated. All samples were amorphous solids and their glass transition temperatures (T-g) were evaluated by using differential scanning calorimetry. Although dextran showed no stabilizing effect on the freeze-dried XOD, the others protected XOD from the activity loss during freeze-drying to a certain extent. It was found that the mixture of disaccharide (sucrose or trehalose) and BSA improved the XOD activity synergistically. The XOD activity of the samples decreased gradually during storage at a temperature range of between 25 and 60 degrees C. Samples stored at temperatures below the T-g showed a lower loss of XOD activity than those stored at just the T-g.

Xanthine oxidase

Freeze-drying

Sucrose

Bovine serum albumin

Glass transition

Manufactures [ 580 ]

eng

Elsevier Sci LTD

Copyright (c) 2009 Elsevier Ltd.

[ISSN] 0308-8146

[DOI] 10.1016/j.foodchem.2009.06.016

[NCID] AA00649137

[DOI] http://dx.doi.org/10.1016/j.foodchem.2009.06.016