Immobilization of beta-glucosidase purified from mandarin (Citrus reticulata) fruit to superparamagnetic nanoparticles and its aroma quality enhancing effect

Abstract

This paper reports on novel and efficient enhancement effects of fruit juice aroma using immobilized β-glucosidase, the enzyme involved in important functions in living organisms, onto superparamagnetic nanoparticles Fe3O4 via carbodiimide β-glucosidase was purified from mandarin (Citrus reticulata) using ammonium sulfate precipitation and hydrophobic interaction chromatography. To be used in this study, superparamagnetic nanoparticles were synthesized and then the shape, size, and magnetism properties of the nanoparticles were characterized. The purified enzyme was immobilized on the nanoparticles. The optimum temperature for β-glucosidase (40 ℃) was increased by 10 ℃ after immobilization, while the optimum pH values of free and immobilized β-glucosidase were 5.5. While the Km and Vmax values of the free enzyme were 0.264 mM and 294 EU, immobilized enzyme’s Km and Vmax were 0.222 mM and 370 EU, respectively. In addition, it was determined that the storage stability of the immobilized enzyme was higher than the free enzyme. When the effect of some metal ions on the enzyme activity was examined, it was observed that Fe+2 increased the enzyme activity while other metals inhibited it. According to the results obtained, the immobilized enzyme had a flavor-enhancing effect on mandarin juice.