Article

Taninos o polifenoles vegetales

Scientia Et Technica 01/2007;
Source: DOAJ

ABSTRACT El término tanino se acuñó históricamente por el uso empírico que se daba a algunos extractos vegetales para el proceso de tanaje o conversión de las pieles de animales en cuero desde hace más de cien años. El desarrollo de las modernas técnicas instrumentales para la elucidación estructural de sustancias orgánicas, permitió el inicio científico en el área de polifenoles vegetales, término sugerido por el doctor Edwin Haslam en lugar de taninos. En esta revisión se discuten algunos hechos históricos, definiciones, técnicas de aislamiento y elucidación estructural, clasificación y aplicaciones de estos compuestos, desde la curtiembre hasta la industria alimenticia.

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    ABSTRACT: Phenolic extracts from witch hazel, Hamamelis virginiana, are efficient antioxidants against fish lipid peroxidation. The impact of fish thermal processes on the hydrolyzable polyphenols from this source was studied. H. virginiana polyphenols included 80% of hydrolyzable tannins, characterized by a mixture of glucose gallates containing from 5 to 10 units of gallic acid, hamamelitannin, and 20% of proanthocyanidins. Structural modifications of the polyphenols during thermal processes were determined by HPLC-MS. Changes in their reducing and free radical scavenging capacities as a result of high temperatures were also determined. Thermal processes triggered a significant breakdown of hydrolyzable tannins with 6-10 galloyl units to give pentagalloyl glucose (PGG). The release of high concentrations of free gallic acid especially in long-term thermally processed samples leads to an increase of the antioxidant ability of heated H. virginiana extracts. Such an increase was evidenced by an increment in the reducing and radical scavenging capacities as well as an improvement in the antioxidant effectiveness for inhibiting lipid oxidation of processed fatty fish muscle.
    Journal of Agricultural and Food Chemistry 03/2010; 58(7):4274-83. DOI:10.1021/jf904032y · 3.11 Impact Factor

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