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Tannins for Wood Adhesives,Foams and Composites
Published in Zhongqi He, Bio-based Wood Adhesives, 2017
From tree bark: Tannins can be extracted from bark and wood of trees at different temperatures and under slightly different conditions, but industrially are always extracted by countercurrent extraction using hot water. In general, the chips of bark are charged in batteries of 6 or 8 connected stainless steel autoclaves, each containing between 10 and 20 tons of bark or wood chips. For some tannins such as mimosa tannin extract the extraction of the bark chips is often done with just hot water at between 70°C and 90°C. The lower temperature is the preferred one because as the temperature increases the yield of extract increases but not the yield of tannins, as other materials, in particular carbohydrates, are extracted more. Thus, if the extract is prepared for adhesives use it is good practice to use temperatures not higher than 70°-75°C. In the case of other tannins such as quebracho tannin from wood chips and pine tannin from bark chips some chemicals are added. In general 2% sodium sulphite or bisulphite and 0.5% of sodium bicarbonates are used for the extraction. These conditions facilitate the extraction of the high molecular weight oligomers by increasing their water solubility.
Microbial Manipulation for Reduced Greenhouse Gas Emissions
Published in Suhaib A. Bandh, Javid A. Parray, Nowsheen Shameem, Climate Change and Microbial Diversity, 2023
Sheikh Firdous Ahmad, Triveni Dutt, Bharat Bhushan
Condensed tannins are complex compounds that bind to proteins and polysaccharides in the feed, decreasing the ability of feed to be digested in the rumen. Condensed tannins modify the rumen’s metabolism, reducing the development of essential metabolites that, in turn, alter the methanogenesis rate, thus helping to mitigate ruminant GHG emissions. However, excessive feeding of tannins can affect the body’s metabolism and reduce the efficiency of animals. A drop-in fiber digestibility reduces hydrogen production in the rumen and is a possible mechanism of action of condensed tannins. However, the reduction of condensed tannin GHG emissions varies with various legumes and depends on tannins’ concentration and composition.
Use of Green Chemistry for Extraction of Bioactive Compounds from Vegetal Sources
Published in Aidé Sáenz-Galindo, Adali Oliva Castañeda-Facio, Raúl Rodríguez-Herrera, Green Chemistry and Applications, 2020
Adriana C. Flores-Gallegos, Ramsés Misael Reyes-Reyna, Paloma Almanza-Tovanche, Marisol Rodríguez-Duarte, Gerardo M. González, Raúl Rodríguez-Herrera, J.A. Ascacio-Valdés
According to its chemical structure, phenolic compounds are very varied, since there are simple molecules such as phenolic acids and very complex molecules such as tannins and lignin. Tannins are polymeric phenolic compounds that bind proteins, denaturing them. Its name derives from the practice of using vegetal extracts to convert skin into leather and these are divided into condensed tannins and hydrolyzable tannins (Ávalos and Pérez, 2009).
Combined effects of sunlight and tempering treatment on the oligomeric procyanidin formation in dried ume (Prunus mume Sieb. et Zucc.)
Published in Drying Technology, 2022
Fu-Yuan Ma, Tzou-Chi Huang, Pratik Nayi, Ho-Hsien Chen
The ume is usually salt-cured and sun-dried for several days to create a Japanese wrinkled pink umeboshi. Dried Umes are dyed with red perilla (Perilla frutescens var. crispa) anthocyanins to obtain an attractive red color on the market. Oenological tannins were found to show copigmentation reaction on malvidin-3-O-monoglucoside in a model wine solution.[14] Oenological tannins, especially oligomeric procyanidins derived from flavan-3-ol, interact with wine components such as anthocyanins to stabilize color in red wine.[15] Procyanidin B2 and procyanidin B1 of overripe seeds from sun-dried grapes show interesting copigmentation effects to modulate grape anthocyanin color and stability in simulated wine conditions.[16] Recently, a significant amount of procyanidins with different degree of polymerization, including procyanidin B2 and procyanidin C1 were detected and characterized in the flesh of Japanese Ume.[10] We hypothesized that the tempering treatment during nighttime may lead to the water redistribution and accumulation on the surface of dried ume so it’s resulted in sun irradiation enhancing the formation of oligomeric procyanidins.
Application of a binary mixture of bio-extract on organic cotton fabric
Published in The Journal of The Textile Institute, 2022
M. Janarthanan, Subrata Das, M. Jayapradeep, S. SumaiyaZainab, S. Venkatesh
Polyphenols compound has higher antioxidant, anti-allergic, anti-platelet, anti-tumor, and anti-inflammatory activities. It is used to cure the tumor, cancer and burned wounds. Phenolic acid compounds have the property of resisting oxidative damage, which leads to various diseases such as degeneration, cardiovascular, cancer, and inflammation. Mainly tumor cells, including leukemia cells, have higher levels of reactive oxygen species (ROS) than other normal cells and are especially sensitive to oxidative cells. Flavanoids compound is responsible for the production of higher antioxidant, anti-allergic, anti-platelet, anti-tumor, and anti-inflammatory activities. It has the properties of curing wounds and killing microbes. Tannins compound have properties such as anti-microbial, anti-inflammatory, anti-cancer and anti-tumor activity, anti-allergic and anti-platelet. It is used to cure cancer, burned wounds, and antidote for poison. The structure of terpenoids has biological activity and can be used to treat many diseases, especially malaria. They have properties such as anti-microbial, anti-inflammatory, anti-cancer, and anti-tumor activity.
Efficient and sustainable treatment of industrial wastewater using a tannin-based polymer
Published in International Journal of Sustainable Engineering, 2021
M. A. Aboulhassan, S. Harif, S. Souabi, A. Yaacoubi
Tannin is a general name given to polyphenol compounds obtained from natural materials, and traditionally used as a tanning agent in the leather industry, hence their name, but one also finds several of them used as coagulant or coagulant aid for water treatment. Lab scale experiments have demonstrated that it is possible to synthesise tannin-derived coagulant from several tannin feedstocks, through a very simple procedure that involves Mannich base reaction. Mannich reaction can be described as the introduction of a quaternary nitrogen inside the tannin complex structure (Tramontini and Angiolini 1994). Tannins undergo Mannich aminomethylation by reaction with an aldehyde and an amine, generating the addition of the carboxyl groups and amines to the tannin structure (Arismendi et al. 2018; Lopes et al. 2019). As a result, tannin Mannich polymer has a higher molecular weight due to formaldehyde and Mannich base crosslinking, and has also an ampholytic character due to the presence of both cationic amines and anionic phenols on the polymer. However, the chemical complexity of tannins and the fact that they are usually taken from natural matrix without a very thorough purification make knowing their structure a very difficult task. A full study about tannins, chemical structure and properties can be found in previous scientific literature (Pizzi 2008).