Comparing Hydrolysable and Condensed Tannins for Tannin Protein-Based Foams.

Tannin-based foams have gained attention as a potential bio-based alternative to conventional synthetic foams. Traditionally, namely condensed tannins (CT) have been used, leaving the potential of hydrolysable tannins (HT) largely unexplored. This study compared the performance of chestnut (HT) and quebracho (CT) in tannin-protein-based foams at different tannin ratios.

Characterisation and tanning effects of purified chestnut and sulfited quebracho extracts.

Unlabelled: Vegetable tannins are environmentally friendly tanning agents. However, they generally impart a dark colour to the tanned leather and highly contribute to the organic load in wastewaters. In this study, we employed a purification protocol separately on chestnut tannin (CT) and sulfited quebracho tannin (QT) to obtain the purified fractions (PCT and PQT).

Effect of Yogurt Enrichment with Wood Tannin during Shelf Life: Focus on Physicochemical, Microbiological, and Sensory Characteristics.

Six food-grade tannins obtained from different woods were used as a source of polyphenolic compounds at two concentrations (0.5% and 1% /) in yogurt formulations and monitored during 3 weeks of storage. Yogurt containing tannins showed significantly higher total phenolic content (+200%), antioxidant activity (+400%), and syneresis (+100%) than control.

Chestnut Wood Mud as a Source of Ellagic Acid for Dermo-Cosmetic Applications.

Ellagic acid (EA) has long been recognized as a very active antioxidant, anti-inflammatory, and antimicrobial agent. However, its low bioavailability has often hampered its applications in health-related fields. Here, we report a phospholipid vesicle-based controlled release system for EA, involving the exploitation of chestnut wood mud (CWM), an industrial by-product from chestnut tannin production, as a largely available and low-cost source of this compound.

Hydrolyzable vs. Condensed Wood Tannins for Bio-based Antioxidant Coatings: Superior Properties of Quebracho Tannins.

Tannins have always been the subject of great interest for their countless properties, first of all their ability to produce functional coatings on a variety of materials. We report herein a comparative evaluation of the antioxidant properties of wood tannin-based coated substrates. In particular, nylon membrane filters were functionalized with chestnut (hydrolyzable) or quebracho (condensed) tannins by dip coating under different conditions.

Antioxidant Properties of Agri-food Byproducts |and Specific Boosting Effects of Hydrolytic Treatments.

Largely produced agri-food byproducts represent a sustainable and easily available source of phenolic compounds, such as lignins and tannins, endowed with potent antioxidant properties. We report herein the characterization of the antioxidant properties of nine plant-derived byproducts. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated the superior activity of pomegranate peels and seeds, grape pomace and pecan nut shell.

Correction: Exhausted Woods from Tannin Extraction as an Unexplored Waste Biomass: Evaluation of the Antioxidant and Pollutant Adsorption Properties and Activating Effects of Hydrolytic Treatments. 2019, , 84.

The authors wish to make the following corrections to their paper [...

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

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.

Biotransformation of industrial tannins by filamentous fungi.

Tannins are secondary metabolites that are widely distributed in the plant kingdom. They act as growth inhibitors for many microorganisms: they are released upon microbial attack, helping to fight infection in plant tissues. Extraction of tannins from plants is an active industrial sector with several applications, including oenology, animal feeding, mining, the chemical industry, and, in particular, the tanning industry.

A mass spectrometry and H NMR study of hypoglycemic and antioxidant principles from a Castanea sativa tannin employed in oenology.

The ethanol extract of the commercial tannin Tan'Activ C, (from Castanea sativa wood), employed in oenology, was subjected to chromatography on XAD-16 affording fractions X1-X5, evaluated for total phenols content (GAE), antioxidant activity (DPPH, ORAC), and hypoglycemic activity (α-glucosidase inhibition). Fraction X3 showed GAE, radical scavenging activity, and α-glucosidase inhibition higher than those of the Castanea sativa extract, and was subjected to chromatography on Sephadex LH-20 to obtain fractions S1-S7, analyzed by HPLC/ESI-MS/MS and H NMR to identify the main active constituents. In fractions with higher antioxidant activity, gallic acid (4), grandinin (5), valoneic acid dilactone (9), 1,2,3-tri-O-galloyl-β-glucose (14), 3,4,6-tri-O-galloyl-β-glucose (15) and galloyl derivative of valoneic acid dilactone (21) were identified as the major constituents.

Fungi from industrial tannins: potential application in biotransformation and bioremediation of tannery wastewaters.

Tannins are a complex family of polyphenolic compounds, widely distributed in the plant kingdom where they act as growth inhibitors towards many microorganisms including bacteria, yeasts, and fungi. Tannins are one of the major components of tannery wastewaters and may cause serious environmental pollution. In the present study, four different tannins (the hydrolysable chestnut ellagitannin and tara gallotannin and the condensed quebracho and wattle tannins) were characterized from a mycological point of view with the aim of selecting fungal strains capable of growing in the presence of high tannin concentration and thus potentially useful in industrial biotransformations of these compounds or in the bioremediation of tannery wastewaters.