Tannase immobilisation by amino-functionalised magnetic Fe3O4-chitosan nanoparticles and its application in tea infusion

Ruyi Li; Guiming Fu; Chengmei Liu; David Julian McClements; Yin Wan; Shaoman Wang; Ting Liu

doi:10.1016/j.ijbiomac.2018.03.077

Tannase immobilisation by amino-functionalised magnetic Fe₃O₄-chitosan nanoparticles and its application in tea infusion

Int J Biol Macromol. 2018 Jul 15:114:1134-1143. doi: 10.1016/j.ijbiomac.2018.03.077. Epub 2018 Mar 16.

Authors

Ruyi Li¹, Guiming Fu², Chengmei Liu³, David Julian McClements⁴, Yin Wan⁵, Shaoman Wang³, Ting Liu³

Affiliations

¹ State Key Laboratory of Food Science and Technology, School of Food, Nanchang University, Nanchang 330047, China; Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA; College of Food Science and Technology, Nanchang University, Nanchang 330031, China; Sino-German Food Engineering Center, Nanchang University, Nanchang 330047, China.
² State Key Laboratory of Food Science and Technology, School of Food, Nanchang University, Nanchang 330047, China; College of Food Science and Technology, Nanchang University, Nanchang 330031, China; Sino-German Food Engineering Center, Nanchang University, Nanchang 330047, China. Electronic address: fuguiming@ncu.edu.cn.
³ State Key Laboratory of Food Science and Technology, School of Food, Nanchang University, Nanchang 330047, China; College of Food Science and Technology, Nanchang University, Nanchang 330031, China; Sino-German Food Engineering Center, Nanchang University, Nanchang 330047, China.
⁴ Department of Food Science, University of Massachusetts Amherst, Amherst, MA 01003, USA.
⁵ State Key Laboratory of Food Science and Technology, School of Food, Nanchang University, Nanchang 330047, China; College of Food Science and Technology, Nanchang University, Nanchang 330031, China.

PMID: 29555512
DOI: 10.1016/j.ijbiomac.2018.03.077

Abstract

The tannase (from Aspergillus niger) was immobilised by glutaraldehyde conjugation to amino-functionalised chitosan-coated magnetic nanoparticles (Fe₃O₄-CS nanoparticles). Fourier-transform infrared spectroscopy and thermo-gravimetric analysis showed that chitosan was coated on the surface of magnetic nanoparticles. Transmission electron microscopy indicated that the synthesised nanoparticles (Fe₃O₄-CS) were almost spherical or ellipsoidal with an average diameter of 5.97 ± 1.25 nm. The stability and functionality of free and immobilised tannase were compared. Both forms of tannase exhibited the same optimal temperature of 30 °C, whereas the optimal pH value of immobilised tannase (pH 4.5) was lower than that of the free tannase (pH 5.5). The pH and thermal stabilities of immobilised tannase were significantly better than those of free tannase. Immobilised tannase retained over 50% of its initial activity after repeated utilisation for eight cycles. Furthermore, the immobilised tannase effectively improve the clarity and colour of black and green tea infusions. These results showed that amino-functionalised Fe₃O₄-CS nanoparticles are an efficient carrier for immobilising tannase, and immobilised tannase can be used in the clarification of tea infusion.

Keywords: Chitosan; Immobilisation; Magnetic nanoparticles; Tannase; Tea.

MeSH terms

Aspergillus niger / enzymology*
Carboxylic Ester Hydrolases / chemistry*
Chitosan / chemistry*
Enzymes, Immobilized / chemistry*
Fungal Proteins / chemistry*
Magnetite Nanoparticles / chemistry*
Tea / chemistry*

Substances

Enzymes, Immobilized
Fungal Proteins
Magnetite Nanoparticles
Tea
Chitosan
Carboxylic Ester Hydrolases
tannase