Condensed tannins from steamed Acacia mearnsii bark

Holzforschung ◽  
2005 ◽  
Vol 59 (3) ◽  
pp. 289-294 ◽  
Author(s):  
Wengui Duan ◽  
Seiji Ohara ◽  
Koh Hashida ◽  
Rei Makino

Abstract The optimum steaming conditions for extraction of condensed tannins from Acacia mearnsii bark were explored, after which characterization of proanthocyanidins from bark steamed under optimum conditions was carried out. The optimum conditions were as follows: steaming time, 30 min; steaming temperature, 140°C; and water volume, 75 ml. The total phenolics content obtained under these conditions amounted to 25.31%, which was much higher than the 21.70% obtained by conventional hot water extraction. Six proanthocyanidin dimers were isolated from the steamed bark. Analysis revealed them to be fisetinidol-(4β-8)-catechin, fisetinidol-(4α-8)-catechin, robinetinidol-(4β-8)-catechin, robinetinidol-(4α-8)-catechin, robinetinidol-(4β-8)-gallocatechin, and robinetinidol-(4α-8)-gallocatechin. Proanthocyanidin polymers were found to consist mainly of prorobinetinidin extender units, similar to those obtained from the same bark by conventional extraction with 70% acetone aqueous solution. However, nuclear magnetic resonance and gel permeation chromatography analyses suggested that during steaming the polymers undergo condensation reactions, as well as inversion of the configuration of interflavanoid bonds.

Author(s):  
Hadear Hanie Amin

In this work the researcher is looking for natural, new, safe, cheap and available compounds that can be used as antimicrobial and antioxidant in the medical and agricultural fields. A sulfated polysaccharide, Ulvan was extracted from Ulva lactuca and purified by cold or hot water-extraction and ethanol-precipitation with yield = 5:10% (w-w). Its appearance and touch like gel. Characterization of active groups of Ulvan was achieved by FT-IR spectroscopy, its content of sulfate = 3.998% (w-w) was determined by Ion Chromatography (IC), its molecular weight = 532.221 Kilo Daltons was determined by Gel permeation chromatography, its thermal stability was evaluated by DSC-TGA, its viscosity = 18 was determined by viscometer apparatus and its antimicrobial activity was studied against human, plant, animal, fish and poultry pathogens. Ulvan showed antioxidant activity with IC50 = 3.04 mg/ml. Its biological activity as an antioxidant and antimicrobial may be a good indication for the use of Ulvan against various pathogens as a preservative in food processing and cosmetics and as antioxidant and antimicrobial in medicine against human pathogen.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4443
Author(s):  
Jiangyan Huo ◽  
Min Lei ◽  
Feifei Li ◽  
Jinjun Hou ◽  
Zijia Zhang ◽  
...  

A novel homogeneous polysaccharide named GEP-1 was isolated and purified from Gastrodia elata (G. elata) by hot-water extraction, ethanol precipitation, and membrane separator. GEP-1, which has a molecular weight of 20.1 kDa, contains a polysaccharide framework comprised of only glucose. Methylation and NMR analysis showed that GEP-1 contained 1,3,6-linked-α-Glcp, 1,4-linked-α-Glcp, 1,4-linked-β-Glcp and 1,4,6-linked-α-Glcp. Interestingly, GEP-1 contained citric acid and repeating p-hydroxybenzyl alcohol as one branch. Furthermore, a bioactivity test showed that GEP-1 could significantly promote the growth of Akkermansia muciniphila (A. muciniphila) and Lacticaseibacillus paracasei (L.paracasei) strains. These results implied that GEP-1 might be useful for human by modulating gut microbiota.


2020 ◽  
Vol 146 ◽  
pp. 431-443 ◽  
Author(s):  
Isabela Pereira Dias ◽  
Shayla Fernanda Barbieri ◽  
Damian Estuardo López Fetzer ◽  
Marcos Lúcio Corazza ◽  
Joana Léa Meira Silveira

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 943-950 ◽  
Author(s):  
Wenwen Fang ◽  
Marina Alekhina ◽  
Olga Ershova ◽  
Sami Heikkinen ◽  
Herbert Sixta

Abstract To upgrade the utilization of kraft lignin (KL) for high-performance lignin-based materials (e.g., carbon fiber), the purity, molecular mass distribution (MMD), and thermal properties need to be improved and adjusted to target values. Therefore, different methods, such as ultrasonic extraction (UE), solvent extraction, dialysis, and hot water treatment (HWT), were applied for the purification of KL. The chemical and thermal properties of purified lignin have been characterized by nuclear magnetic resonance, Fourier transform infrared, gel permeation chromatography, elemental analysis, differential scanning calorimetry, and thermogravimetric analysis. The lignin fractions obtained by UE with ethanol/acetone (E/A) mixture (9:1) revealed a very narrow MMD and were nearly free of inorganic compounds and carbohydrates. Further, the E/A-extracted lignin showed a lower glass transition temperature (Tg) and a clearly detectable melting temperature (Tm). Dialysis followed by HWT at 220°C is an efficient method for the removal of inorganics and carbohydrates; however, lignin was partly forming condensed structures during the treatment.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 19-26 ◽  
Author(s):  
BILJANA M. BUJANOVIC ◽  
MANGESH J. GOUNDALKAR ◽  
THOMAS E. AMIDON

In conventional pulping technologies, lignin is used mainly as a low-cost source of energy. Small quantities of industrially produced lignin are used for the production of chemicals and materials. Biorefinery technologies are emerging that have an ultimate goal of replacing fossil sources for the production of fuels and other products. To achieve this goal effectively, biorefinery technologies must take advantage of lignin as the most abundant natural aromatic polymer and use it to add higher-value products to product portfolios. Lignin has the potential to be used in making a broad range of high-quality products, including carbon fibers, thermoplastics, and oxygenated aromatic compounds. Existing processes focus primarily on the quality of cellulose and result in a severely modified and contaminated lignin of relatively low value. Lignin produced in more flexible biorefinery operations is more uniform and less contaminated than currently available industrial lignins, opening the door for broader applications of lignin and lignin products. The results of isolation and characterization of lignin dissolved during hot-water extraction and some potential applications of this lignin are discussed.


Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 410 ◽  
Author(s):  
Richardly Lenz Clove Dupré ◽  
Lotfi Khiari ◽  
Jacques Gallichand ◽  
Claude Alla Joseph

Despite its inconveniences, the most recognized method to extract boron from soils is that of hot water extraction (BHW), which is used for diagnostics and recommendations. However, the Mehlich-3 (M3) method is widely used to extract and diagnose several elements at once (P, K, Ca, Mg, Al, B, Cu, Zn, Fe, and Mn) and is well adapted to routine analyses. The objective of our study was to develop a soil diagnostic and recommendation system for boron as a function of measured BM3 (and other interacting elements), crop type, and spreading methods. This system is based on three databases from either the international literature or the chemical characterization of acidic-to-neutral soils typical from Québec (Canada). The first database came from the characterization of 365 samples typical of Québec soils; it has been used to predict, by the AutoML (Automatic Machine Learnig) supervised learning algorithm, BM3 as a function of a set of parameters from the following: BHW, pHW, organic carbon (OC), CaM3, KM3, and MgM3. Depending on the parameters used, the R2 between the measured and observed BM3 varied from 0.36 to 0.99. This database allowed us to define two classifications for soil boron diagnostics and fertility evaluation. The Cate–Nelson analysis for these two models allowed us to define three boron fertility classes: Low, medium and high; that is 0.00–0.23, 0.23–0.58, and 0.58–3.70 mg B kg−1, respectively, for BHW, and 0.00–0.65, 0.65–1.03, and 1.03–12.70 mg B kg−1, respectively, for BM3. The third database was extracted from 130 yield responses to increasing levels of boron; it was used to define a recommendation model for boron, based on AutoML, as a function of BM3, pHW, the crop boron requirement (medium, high), and the type of spreading (broadcast, sidedress, foliar spraying). This model resulted in an R2 of 0.63.


2021 ◽  
Vol 45 ◽  
Author(s):  
Sarah Rebeka Rodrigues Marques ◽  
Tatiane Kelly Barbosa Azevêdo ◽  
Aline Rogéria Freire de Castilho ◽  
Renata Martins Braga ◽  
Alexandre Santos Pimenta

ABSTRACT Condensed tannins are chemical compounds derived from the secondary metabolism of plants. They are of particular interest due to their broad range of technological uses and applications. The objective of this study was to extract, quantify, and characterize by Fourier-transform infrared spectroscopy (FTIR) the bark tannins of four forest species grown in Northeast Brazil: Acacia mangium, Azadirachta indica, Mimosa tenuiflora, and Mimosa caesalpiniifolia. Bark samples were collected from 5 trees of each species grown in a five-year-old forest stand. Samples were collected, grounded, and submitted to extraction with hot water, then measured to determine total solids content (TSC), Stiasny number (SN), and condensed tannins content (CTC). FTIR spectra were acquired from tannin samples fixed in potassium bromide pellets. Among the four species, M. tenuiflora presented the highest CTC, equal to 23.4%, and the purest crude hot-water extract with SN of 91.27%. Based on FTIR characterization, tannins from M. caesalpiniifolia, A. indica, and A. mangium barks were classified as proanthocyanidins and those from M. tenuiflora bark as prodelphinidins.


2011 ◽  
Vol 236-238 ◽  
pp. 1174-1177 ◽  
Author(s):  
Su Feng Zhang ◽  
Heng Yang

The alkaline pulping properties of wheat straw, which had been hemicelluloses pre-extracted with hot water, were studied. In this work, the process of hot-water extraction at various temperatures, reaction time and other conditions were investigated. The straws pre-extracted or not were made into pulp with NaOH-AQ at same conditions. Then the effects of pre-extraction on properties of straw pulp were studied. The results show that the yield, Kappa number and viscosity of the pulp are affected significantly by hemicelluloses pre-extraction process. The chemicals charge of the extracted straw in the pulping process is lower and shorter cooking time needed, the maximum pulping temperature reduced. These effects indicate that the action of hot-water pre-extraction before alkaline pulping is able to reduce effluent discharge and chemical demand to pulp, and it would be energy-saving. In this experiment, the optimum conditions of hot-water pre-extraction were: maximum temperature 140°C, heat-up time 30min, time at maximum temperature 60min and liquor ratio 1:10. The optimal pulping conditions were: alkali charge 12%, maximum temperature 155°C, heat-up time 90min, and holding time at maximum temperature 60min.


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