Immobilization of Laccase on Magnetic Chelator Nanoparticles for Apple Juice Clarification in Magnetically Stabilized Fluidized Bed

Abstract

The juice clarification, one of the key steps in juice processing, suffers from haze formation that results from residual phenolic compounds. In this study, laccase was immobilized on metal-chelated magnetic silica nanoparticles and used for continuous juice clarification in a magnetically stabilized fluidized bed (MSFB) assisted by alternating magnetic field. Furthermore, a new combination of laccase catalysis and microfiltration was developed for the juice clarification. Immobilized laccase provided high relative activity within broader ranges of pH and temperature compared to the free enzyme. Magnetic immobilized laccase exhibited the best reaction rate of 12.1 μmol g –1 min –1 for catechol oxidation under the alternating magnetic field of 400 Hz, 60 Gs. No activity loss occurred in immobilized laccase after 20 h continuous operation of juice treatment in MSFB under an alternating magnetic field. Combined with microfiltration after treatment with immobilized laccase, the color of apple juice was decreased by 33.7%, and the light transmittance was enhanced by 20.2%. Furthermore, only 16.3% of phenolic compounds and 15.1% of antioxidant activity was reduced for apple juice after the clarification. By this combination strategy, the apple juice possessed good freeze–thaw and thermal stability.

Sono‐activation of food enzymes: From principles to practice

“…Some researchers drew conclusions that ultrasound treatment could reduce the fluorescence intensity yet without changing λ max for enzyme proteins. Such variation trends have been reported for ultrasound‐activated glucoamylase (Wang et al., 2020), cellulase (Subhedar & Gogate, 2014; Wang et al., 2012b), pectinase (Ma et al., 2015), and lipase (Nadar & Rathod, 2017a). In these cases, authors have ascribed the phenomena to the unfolding of enzyme protein molecules during sonication.…”

Applications and immobilization strategies of the copper-centred laccase enzyme; a review

“…Laccase has found application in food industry as a food additive for stabilization of beverages, wines and beers [ 266 , 267 , 268 ], clarification of fruit juices [ 269 , 270 , 271 ], baking [ 272 , 273 , 274 , 275 ], sugar beet pectin gelation [ 276 ], and improvement of food sensory parameters [ 277 ]. It is also used in the detection of phenolic compounds in beverages, wines and beers [ 278 ], as well as bioremediation of food industry waste water.…”

Propelling of Enzyme Activity by Using Different Triggering Strategies: Applications and Perspectives

“…In another report, the laccase was immobilized on Cu 2+ -chelated magnetic silica NPs, and the immobilized enzyme in a magnetically stabilized fluid bed supported by an alternating magnetic field was used for continuous juice clarification . The immobilized enzyme showed the best reaction rate of 12.1 μmol g –1 min –1 for catechol oxidation under an alternating magnetic field of 400 Hz and 60 G. No loss of activity was observed in the immobilized laccase after 20 h of continuous juice treatment in the system under an alternating magnetic field.…”