Activity of laccase from Trametes versicolor was assayed directly in virgin olive oil (VOO) samples. Laccase-treated oils led to the formation of insoluble precipitate and to significant qualitative and quantitative changes of their polyphenol composition. At the extreme condition of oil/laccase incubation (60°C for 1h) depletion of oleuropein and o-diphenols was estimated up to 90% and 77%, respectively. Results of Rancimat test (130°C and 20Lh-1) and oven-test (60°C) evidenced controversial effects on the VOO oxidative stability. At high temperature, induction time of laccase-treated oils was found to be similar or even lower than the one recorded in the chemically-dephenolized oils; therefore, enzyme treatment induced a pro-oxidant effect. Conversely, during the storage at 60°C, all the laccase-treated oils showed an improvement on their oxidative stability compared to the fresh oil counterparts. Experimental data suggest that polyphenol enzymatic-oxidation generated oil by-products which manifest higher radical scavenging or conversely pro-oxidant property, depending on the treatment temperature and storage conditions of the oils. © 2013 Elsevier Ltd.

Effects of polyphenol enzymatic-oxidation on the oxidative stability of virgin olive oil

Antonella, De Leonardis
Primo
;
Ruggero, Angelico
Secondo
;
Vincenzo, Macciola;Andrea, Ceglie
Ultimo
2013-01-01

Abstract

Activity of laccase from Trametes versicolor was assayed directly in virgin olive oil (VOO) samples. Laccase-treated oils led to the formation of insoluble precipitate and to significant qualitative and quantitative changes of their polyphenol composition. At the extreme condition of oil/laccase incubation (60°C for 1h) depletion of oleuropein and o-diphenols was estimated up to 90% and 77%, respectively. Results of Rancimat test (130°C and 20Lh-1) and oven-test (60°C) evidenced controversial effects on the VOO oxidative stability. At high temperature, induction time of laccase-treated oils was found to be similar or even lower than the one recorded in the chemically-dephenolized oils; therefore, enzyme treatment induced a pro-oxidant effect. Conversely, during the storage at 60°C, all the laccase-treated oils showed an improvement on their oxidative stability compared to the fresh oil counterparts. Experimental data suggest that polyphenol enzymatic-oxidation generated oil by-products which manifest higher radical scavenging or conversely pro-oxidant property, depending on the treatment temperature and storage conditions of the oils. © 2013 Elsevier Ltd.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11695/45827
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