Vegetable tissue from latania sp.: an extraordinary source of naturally immobilized enzymes for the detection of phenolic compounds

Abstract

This paper describes the exciting characteristics of Latania sp. as a source of naturally immobilized polyphenol oxidase enzymes. Tissues from fruits of this palm tree present remarkably high enzymatic activity and this characteristic was explored for amperometric quantification of catechol and dopamine. These compounds were determined by the electrochemical reduction of their oxidation products on glassy carbon, after a biocatalytic conversion to quinone products. The quantification of these compounds was achieved in three different ways: by using an on-line tissue-based reactor associated with a flow injection analysis system; by incorporation of unripe tissue in carbon paste electrodes; and by exploring the use of dried tissue to construct reactors or modified carbon paste electrodes. This appears to be the first time that dry tissues have been utilized as an enzymatic source to construct enzymatic reactors, employed in the quantification of phenolic products. The last approach can address the unavailability of vegetable tissues (even out of the harvest season), and permits the dried material to be processed in a grinder, producing particles that can be selected accordingly to their size. Very high sensitivity, excellent reproducibility and long-term stability are some of the advantages obtained by using this tissue as a polyphenol oxidase source. Analogous measurements of phenol, based on the phenolase activity of Latania sp., are also reported.