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Determination of phenolics concentration using cross-linked phenol oxidase aggregates

Ertürk, Bedriye Durhan
The main object of the presented study was investigation of the use of cross-linked enzyme (tyrosinase) aggregates (CLTA) obtained from crude mushroom extract for a rapid phenolic content analysis in wines. In addition, a comparison of phenolic characteristics of Turkish red wines was performed. Reproducible and reliable results in total phenolic measurement were obtained with CLTAs similar to pure tyrosinase and tyrosinase obtained from crude mushroom extract. Measurement of total phenolic content is possible both in standard solutions and in complex matrices, such as wine. In a very short time period, 10 seconds, phenolics content in red and white wines produced from grapes of Turkey were investigated by using CLTAs. Results were consistent when compared to a well known phenolic measurement method, Folin-Ciocalteau. CLTAs exhibited very high operational stability and retained more than 90% of its activity after 30th use. Moreover, it showed good shelf-life stability for about 2 months storage by maintaining 90% of its maximum activity. So, use of CLTAs prepared from crude mushroom extract is an effective, fast and cheap alternative in total phenolics measurements in wines. Moreover, a novel catalase phenoloxidase (CATPO) produced by a fungal microorganism, Scytalidium thermophilum, was studied to check its capabilities in phenolics measurements. This novel catalase phenol oxidase showed similarly good results, exhibiting widesubstrate selectivity.