Exhausted Woods from Tannin Extraction as an Unexplored Waste Biomass: Evaluation of the Antioxidant and Pollutant Adsorption Properties and Activating Effects of Hydrolytic Treatments.

Lucia Panzella,Federica Moccia,Maria Toscanesi,Samuele Giovando,Alessandra Napolitano,Marco Trifuoggi

doi:10.3390/antiox8040084

Lucia Panzella, Federica Moccia + Show 4 more

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https://doi.org/10.3390/antiox8040084

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Journal: Antioxidants	Publication Date: Apr 1, 2019
Citations: 21	License type: CC BY 4.0

Affiliation: University of Naples Federico II

Abstract

Exhausted woods represent a byproduct of tannin industrial production processes and their possible exploitation as a source of antioxidant compounds has remained virtually unexplored. We herein report the characterization of the antioxidant and other properties of practical interest of exhausted chestnut wood and quebracho wood, together with those of a chestnut wood fiber, produced from steamed exhausted chestnut wood. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated good antioxidant properties for all the materials investigated, with exhausted chestnut wood, and, even more, chestnut wood fiber exhibiting the highest activity. High efficiency was observed also in the superoxide scavenging assay. An increase of the antioxidant potency was observed for both exhausted woods and chestnut wood fiber following activation by hydrolytic treatment, with an up to three-fold lowering of the EC50 values in the DPPH assay. On the other hand, exhausted quebracho wood was particularly effective as a nitrogen oxides (NOx) scavenger. The three materials proved able to adsorb methylene blue chosen as a model of organic pollutant and to remove highly toxic heavy metal ions like cadmium from aqueous solutions, with increase of the activity following the hydrolytic activation. These results open new perspectives toward the exploitation of exhausted woods as antioxidants, e.g., for active packaging, or as components of filtering membranes for remediation of polluted waters.

Highlights

In the light of their marked antioxidant properties, phenolic polymers from natural sources have been the focus of increasing interest as sustainable functional materials for the wide range of potential applications, for example as biocompatible materials for biomedical devices or as active components in functional food packaging [1,2,3,4,5,6,7]
We report the the characterization characterization of of the the antioxidant antioxidant properties properties of of exhausted exhausted chestnut chestnut and quebracho wood, together with those of a chestnut wood fiber produced from steamed exhausted quebracho wood, together with those of a chestnut wood fiber produced from steamed exhausted chestnut wood
[4,25,26], we investigated of natural phenolic polymers or wastes leads to materials with potent antioxidant efficiency [4,25,26], the properties of the exhausted woodsof and wood fiber materials obtained by fiber such treatment we investigated the properties thechestnut exhausted woods and chestnut wood materials in comparison withtreatment those of the untreated materials, showing most cases a significant enhancement obtained by such in comparison with those of theinuntreated materials, showing in most of the activity

Summary

Introduction

In the light of their marked antioxidant properties, phenolic polymers from natural sources have been the focus of increasing interest as sustainable functional materials for the wide range of potential applications, for example as biocompatible materials for biomedical devices or as active components in functional food packaging [1,2,3,4,5,6,7]. Tannins are traditionally ranked into the Antioxidants 2019, 8, 84; doi:10.3390/antiox8040084 www.mdpi.com/journal/antioxidants hydrolyzable and the condensed or non-hydrolyzable classes. Commonly hydrolyzable and the condensed or non-hydrolyzable classes. Known as chestnut tannin, is composed mainly of hydrolyzable ellagitannins suchwood as castalagin commonly known as chestnut tannin, is composed mainly of hydrolyzable ellagitannins such as and its isomer vescalagin, whereas quebracho tannin, extracted from the hardwood of Shinopsis castalagin and its isomer vescalagin, whereas quebracho tannin, extracted from the hardwood of balansae/lorentzii, comprise mainly condensed tannins of which linear profisetinidins represent the Shinopsis balansae/lorentzii, comprise mainly condensed tannins of which linear profisetinidins major constituents (Figure 1) [1,15,16]

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