Tannins are a group of compounds belonging to a larger class of substances known as polyphenols, which are a type of antioxidant.
Tannins are found in various plant tissues, including leaves, seeds, bark, wood, and fruit.
They play several key roles in plant physiology, such as protection against predation and contributing to plant growth.
There are two main types of tannins: hydrolyzable tannins and condensed tannins.
Hydrolyzable tannins can be broken down into simpler substances by the action of water and certain enzymes.
They are usually complex structures made up of sugar molecules linked to other components such as gallic acid or ellagic acid.
Condensed tannins, also known as proanthocyanidins, are polymers of flavonoid units, and they do not readily hydrolyze.
From a nutritional and health perspective, tannins are often discussed in terms of their antioxidant properties, which can help
to neutralize harmful free radicals in the body. However, because they can inhibit the absorption of certain nutrients in the
digestive system, they are also considered anti-nutritional factors in some contexts.
In the context of food and beverage, tannins contribute to flavor complexity, color, and the aging process of wine. They also
play a role in traditional processes such as the tanning of leather, where they bind to proteins in animal hides and make
them resistant to water and microbial damage.
Some points regarding tannins in herbal leaf extracts are provided below:
Plant Types
- Herbs like witch hazel, sage, rosemary, and yarrow are known for their high tannin contents.
Astringency - Tannins in herbal leaf extracts are responsible for the
astringent properties of many of these herbs. Astringency is the drying, tightening, and sometimes puckering sensation
that you experience when you consume certain foods or drinks. For example, it's the tannins that give black tea, red wine, and certain fruits like
unripe apples or persimmons their characteristic mouthfeel.
Hydrolyzable Tannins - These are found in some herbs like witch hazel
(Hamamelis virginiana). Two types of phenolic acids commonly found in hydrolyzable tannins are gallic acid and ellagic acid.
Some points regarding tannins in bark are provided below:
Role
- Tannins play essential roles in the tree's defenses against pests and diseases, and they contribute to the tree's growth and repair.
Hydrolysable Tannins - These tannins can be hydrolyzed into simpler phenolic
compounds, such as gallic acid or ellagic acid, and a sugar molecule. They are found in the bark of many tree species, including oak,
chestnut, and myrobalan.
Condensed Tannins - Also known as proanthocyanidins,
these tannins are polymers of flavonoid units and are not readily hydrolysed. They are found in high quantities in the bark of some trees,
like pine and spruce.
Industry Applications - Bark tannins are widely used in industry. For instance, the
bark of oak trees is a major source of tannins used in the tanning of leather. During the tanning process, the tannins bind to the
collagen proteins in the animal hides, making them resistant to decomposition and conferring durability.
Health Applications - Bark tannins have antioxidant properties and potential
antimicrobial, antiviral, and anticancer effects.
Phlorotannins are the main tannins in brown seaweed, being unique to this biomass type. The content of these compounds can vary
significantly depending on the seaweed species, the stage of growth, and environmental factors such as sunlight, temperature,
and nutrient availability. Some of the the different types of phlorotannins
seen in brown seaweed are described below:
Phlorethols
- These are phlorotannins where the phloroglucinol units are connected by ether linkages. An example of a phlorethol found in brown
seaweeds like Fucus vesiculosus (bladderwrack) is tetraphlorethol A.
Fuhalols and Fucols - Fuhalols are similar to phlorethols but have additional
hydroxyl groups. Fucols, on the other hand, consist of phloroglucinol units linked through aryl-aryl bonds. An example of a fucol
is trihydroxyfucol, which has been found in species like Ascophyllum nodosum (knotted wrack).
Eckols - These phlorotannins contain a dibenzodioxin linkage.
An example is eckol, which has been identified in Ecklonia cava, a type of brown seaweed common in Korea and Japan.
Carpotannins - These are a group of phlorotannins with a unique structure,
where the phloroglucinol units are linked through both aryl-aryl and ether bonds.
An example of this type is carpogel, found in Carpomitra costata.
Fucophlorethols - These are complex phlorotannins where fucol and phlorethol
units are connected through ether linkages.
The extraction process, including the solvents and methods used, can influence the concentration and types of tannins present in the final extract.
It is often the case that a balance needs to be found between fully-extracting all tannins while also ensuring that the compounds that are
obtained are of a high quality and not degraded.
At Celignis we have extensive experience in the design and optimisation of extraction protocols for a wide variety of chemical constituents from
many different biomass types. If needed we can also work on processes to separate and purify the target compounds.
Click here to read more about Celignis's Bioprocess Development Services for the extraction of
chemicals from biomass.
€1.6m Funding Success for Celignis in 2024 CBE-JU Calls
We have secured funding for involvement in 4 collaborative research projects
We are delighted to announce that Celignis has been successful in 4 project proposals submitted for funding to the Circular Bio-based Europe Joint Undertaking (CBE JU) programme.
These projects will provide funding of 1.6m EUR to Celignis over the next few years and build upon the 3 projects (worth 1.5m EUR) we secured last year and the 4 previous CBE/BBI projects that Celignis participated in.
Details on the projects are provided below:
WoodVALOR - This RIA project concerns the valorisation of contaminated/post-consumer wood waste (WW) via: (i) thermal conversion to biochar; and (ii) fractionation followed by conversions to paints & coatings ingredients. Celignis is involved in the chemo-enzymatic fractionation of decontaminated wood (DW) to sequentially extract/purify lignin and hemicellulose, and in developing hemicellulose-based emulsifiers/stabilizers and binder monomers for industrial formulations. Additionally, Celignis is involved in metals/mineral recovery from decontamination wastewater using
New Publication from a Celignis Bioprocess Development Project
The article, available in "Biomass Conversion and Biorefinery" is entitled "Process development for efficient pectin extraction from tobacco residues and its characterisation"
We are please to announce the publication of a peer-reviewed scientific article based on some of the research outputs of a Bioprocess Development Service (BDS) project undertaken by Celignis.
The article, entitled "Process development for efficient pectin extraction from tobacco residues and its characterisation" details the results of experiments targeting the optimised extraction of pectin from the laminae of a number of different varieties of tobacco plants. These tobacco-derived pectins were found to have a medium molecular weight and low methoxy content and our findings indicated that this feedstock could be suitable for the production of pectin with dietary applications.
Meeting takes place at the coordinator's (ITA) headquarters in Zaragoza, SPAIN
Celignis personnel are today attending the kick-off meeting of the CBE-JU project MANUREFINERY at the facilities of the project's coordinator (ITA) in Zaragoza, Spain.
MANUREFINERY concerns the development of a small, decentralised, modular biorefinery concept for farms that converts manure and ammonia emissions into seven marketable bio-ingredients (animal-feed proteins, caproic acid, and fertiliser salts/ashes). The solution integrates fixed/mobile units across three valorisation lines (gas, liquid, solid) and a digital twin for optimisation and scale-up, targeting TRL6-7 validation on four EU demo farms.
Celignis has a number of key roles in the project, including:
- Comprehensive analysis of the feedstocks and products of the process.
Meeting takes place at the coordinator's (AIMPLAS) headquarters in Valencia, Spain
PROMOFER, is an Innovation Action project funded by the CBE-JU, under topic HORIZON-JU-CBE-2023-IA-03 (Improve Fermentation Processes (Including Downstream Purification) To Final Bio-Based Products).
This project started in June 2024 with Celignis, an SME partner and full industry BIC member, playing a pivotal role in the project. Our core activities include undertaking the pre-treatment and hydrolysis of lignocellulosic biomass at scaled-up (TRL7, 1 m3) volumes. The resulting sugars are then provided to other partners for downstream fermentations.
Today Celignis's CIO Lalitha is attending the kick-off meeting of the project, at coordinator AIMPLAS's headquarters in Valencia, Spain.
We're attending the kick-off meeting for BIONEER in Trondheim, Norway (SINTEF)
Lalitha is attending the kick-off meeting of our CBE-JU project BIONEER, located at the coordinator's (SINTEF) premises in Trondheim, Norway.
BIONEER has the title "Scaled-up Production of Next-Generation Carbohydrate-Derived Building Blocks to Enhance the Competitiveness of a Sustainable European Chemicals Industry". It is a 4-year Innovation Action project with 7.5m EUR of funding provided by the CBE-JU.
Celignis plays a key role in BIONEER, being responsible for the scaled-up (TRL7) production of platform chemicals.
Thanks for contacting us. One of our representatives will be in contact with you shortly regarding your inquiry. If you ever have any questions that require immediate assistance, please call us at +353 61 371 725.
Contact Us
Thanks for contacting us. One of our representatives will be in contact with you shortly regarding your inquiry. If you ever have any questions that require immediate assistance, please call us at 319-509-3350.
Contact Us
Somthing went wrong! Please call us at
319-509-3350
or send us a email at
info@celignis.us with your enquiry.
Contact Us
Please provide a valid email id.
News letter signup
Thanks for signing our newsletter.
Newsletter
Message
Newsletter signup
Our newsletter provides monthly updates on new types of biomass analyses and articles on the development of innovative bioprocesses.
Newsletter
Subscribe to our newsletter and stay updated.
NOTE : We use cookies to improve our website and to give you the best experience. If you continue using our website, we'll assume that you are happy to receive all cookies on this website.