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Changes in commercial glucose oxidase activity by high pressure homogenization

Tribst, Alline Artigiani Lima, Cristianini, Marcelo
Innovative food science & emerging technologies 2012 v.16 pp. 355-360
aqueous solutions, enzyme activity, enzyme stability, food industry, food matrix, glucose, glucose oxidase, homogenization, oxygen, pH, temperature
High pressure homogenization (HPH) has been described as a process able to change enzyme activity and stability of enzymes. This study investigated the HPH effects on commercial glucose oxidase (GO) activity. Enzyme solutions at pH5.0, 5.7 and 6.5 were processed at pressures 50, 100, and 150MPa. The HPH effects were determined by the enzyme residual activity measured at 15, 50 and 75°C immediately after homogenization and after 1day of storage. Results showed that low pressures (50MPa) reduced the GO relative activity at all temperatures evaluated when samples were homogenized at pH5.0. However, a relative recovery of enzyme activity was observed when homogenization was carried out at pressures of ≥100MPa. For samples processed at pH5.7, the homogenization at 100MPa reduced the relative enzyme activity at 15 and 50°C. On the contrary, a 25% improvement on GO relative activity at 75°C was observed after homogenization at 150MPa. For samples homogenized at pH6.5, the process continuously reduced the GO relative activity at 15°C and almost no changes were observed when activity was evaluated at 50 and 75°C. After 1day, the GO relative activity of homogenized samples could increase up to 400%, as compared to the native one stored under the same condition. The results confirmed that HPH changes the GO activity, being able to increase or decrease it. This activity change may be associated to continuous modifications in enzyme structure due to homogenization pressure and pH of solution. Additionally, the GO relative stability increase in aqueous solution highlights HPH as an interesting tool to improve GO performance, expanding the potential application range of glucose oxidase in food industry. INDUSTRIAL RELEVANCE: GO is an important enzyme in food industry due to its ability to consume oxygen and glucose. However its high instability on food matrix limits GO application. Therefore, the application of high pressure homogenization as an emerging technology to keep enzyme activity in aqueous solution is interesting to improve GO applications.