Improving physicochemical stability of glucose oxidase using W1/O/ W2 emulsion

Fabrication of water-in-oil-in-water (W1/O/W2) emulsion loaded with glucose oxidase (GOX) and the physicochemical stability of W1/O/W2 emulsion against environmental stress were investigated. GOX and olive oil were firstly sheared to produce water-in-oil (W1/O) emulsion. Gelatin, sodium carboxymethyl cellulose (CMC) and the prepared W1/O emulsion were further sheared to produce double emulsions (W1/O/W2). As contrasted to free enzyme, the double emulsions showed enhanced heat resistance, the thermal stability of W1/O/W2 emulsion increased 210.1%. Hence, differential scanning calorimetry (DSC) thermograms results showed the double emulsions has a higher heat resistance, the maximum heat absorption peak (melting point) at 106.47 degrees C. Double emulsions also showed the highest pH stability and ethanol stability, increasing about 1.2 folds and 1.64 folds, respectively. In addition, particle size of double emulsions was about 1.68 +/- 0.10 mu m, which partly contribute to storage stability, the turbidity changes from 0.501 +/- 0.026 to 0.437 +/- 0.029 after a month of storage at 4 degrees C. Overall, the carboxyl group of the polysaccharide in the double emulsions interacted with the amine group of the protein to form an amide complex, which improved the physicochemical stability of the W1/O/W2 emulsion. Higher thermal stability of GOX fabricated by double emulsions is a promising technique, which expected to expand the applications such as bread improver and feed additive in food and feed industry.