Autori: Michaela Dina Stanescu · Simona Gavrilas · Roland Ludwig ·Dietmar-Haltrich, Vladimir I. Lozinsky

Editorial: Springer, Eur Food Res Technol, 234, p.655-662, 2012.

Rezumat:

A new biocatalyst was prepared by the immobilization of a Trametes pubescens laccase, into a wide-pore poly(vinyl alcohol) cryogel. The known enzyme was produced and purified by the previously described procedure.
The resulted laccase (yield 40%) has an activity of 46.4 U/mg and 12.51 mg/mL protein content. The enzyme was subsequently immobilized in a functionalized macroporous cryogel beads by a covalent immobilization
technique. The time dependence of the immobilization process and the enzyme loading of the carrier material
(5.2 mg/g cryogel) were determined by measuring the decrease of protein amount in the enzyme solution. In conversion experiments, a higher stability of the immobilized
biocatalyst compared to the free enzyme was evidenced.
Steady-state kinetic characterization of four phenols (catechol,
caffeic and chlorogenic acids, and catechin) has been
performed with free and immobilized laccase, the catalytic
parameters being determined and compared. The effect of
both laccases (free and immobilized) on the phenol content of retailed apple juice samples, having the same initial composition, was also investigated by working in batch
conversion. The variation in phenolic compound content has been compared with that of an untreated apple juice
sample having initially the same content of phenolic compounds.
A number of advantages resulted in using the immobilized laccase for the apple juice treatment (conservation
to some extent of enzyme activity, higher content of phenols preserved, easy separation of the enzyme from the
apple juice, therefore avoiding the possible unhealthy effects due to the remaining protein, etc.).

Cuvinte cheie: Emzime imobilizate, suport de criogel-PVA, Cinetica oxidarii unor compusi fenolici, tratare suc de mere // Immobilized laccase, Poly(vinyl alcohol) cryogel carrier, Oxidation kinetics of phenolic compounds, Apple juice treatment

URL: http://www.springer.com/food+science/journal/217