Hot water extraction of Norway spruce (<i>Picea abies</i> [Karst.]) bark: analyses of the influence of bark aging and process parameters on the extract composition

Bianchi, Sauro; Koch, Gerald; Janzon, Ron; Mayer, Ingo; Saake, Bodo; Pichelin, Frédéric

doi:10.1515/hf-2015-0160

Cited by 37 publications

(26 citation statements)

References 44 publications

(61 reference statements)

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“…The reasons for changes in bark chemical quality during the storage and weathering include enzymatic reactions (e.g., living cell respiration) and biological degradation (due to various bacteria and fungi), as well as thermo-chemical oxidative reactions at the presence of adequate oxygen and moisture [ 23 , 24 , 26 , 32 ]. Day-light-induced processes may also have taken place, leading to the formation of polymers and smaller oligomers but also degradation of structures, especially in the case of photosensitive stilbenes [ 9 , 17 , 33 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

Fate of Antioxidative Compounds within Bark during Storage: A Case of Norway Spruce Logs

et al. 2020

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Softwood bark is an important by-product of forest industry. Currently, bark is under-utilized and mainly directed for energy production, although it can be extracted with hot water to obtain compounds for value-added use. In Norway spruce (Picea abies [L.] Karst.) bark, condensed tannins and stilbene glycosides are among the compounds that comprise majority of the antioxidative extractives. For developing feasible production chain for softwood bark extractives, knowledge on raw material quality is critical. This study examined the fate of spruce bark tannins and stilbenes during storage treatment with two seasonal replications (i.e., during winter and summer). In the experiment, mature logs were harvested and stored outside. During six-month-storage periods, samples were periodically collected for chemical analysis from both inner and outer bark layers. Additionally, bark extractives were analyzed for antioxidative activities by FRAP, ORAC, and H2O2 scavenging assays. According to the results, stilbenes rapidly degraded during storage, whereas tannins were more stable: only 5–7% of the original stilbene amount and ca. 30–50% of the original amount of condensed tannins were found after 24-week-storage. Summer conditions led to the faster modification of bark chemistry than winter conditions. Changes in antioxidative activity were less pronounced than those of analyzed chemical compounds, indicating that the derivatives of the compounds contribute to the antioxidative activity. The results of the assays showed that, on average, ca. 27% of the original antioxidative capacity remained 24 weeks after the onset of the storage treatment, while a large variation (2–95% of the original capacity remaining) was found between assays, seasons, and bark layers. Inner bark preserved its activities longer than outer bark, and intact bark attached to timber is expected to maintain its activities longer than a debarked one. Thus, to ensure prolonged quality, no debarking before storage is suggested: outer bark protects the inner bark, and debarking enhances the degradation.

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Section: Resultsmentioning

confidence: 99%

Fate of Antioxidative Compounds within Bark during Storage: A Case of Norway Spruce Logs

et al. 2020

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“…In general, these extracts are obtained through the use of a hot pressurized sulfite aqueous solution [ 31 ]. Unfortunately, the amount of unextracted PACs can be as high as 62.5% in white grapes [ 32 ] and 62.3% in Norway spruce bark [ 33 ], resulting in a low yield process and a final extract that is mostly composed of PACs with lower degree of polymerization that are not as effective as the ones with higher degree of polymerization. Additionally, in order to achieve the intended mean degree of polymerization (mDP) further downstream processing is needed, making its final price prohibitive for most applications.…”

Section: Introductionmentioning

confidence: 99%

Tuning of Proanthocyanidin Extract’s Composition through Quaternary Eutectic Solvents Extraction

et al. 2020

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Currently available proanthocyanidins extraction methods rely on dedicated crops and have low specificity and yield which limits their industrial application. Consequently, the development of novel methodologies and the use of sustainable sources is of great importance. Eutectic solvents have been proposed has good alternatives for conventional solvents due to their low price, easiness of preparation, biocompatibility and ability of being custom made to a specific application. Herein the effective extraction of proanthocyanidins from grape pomace and the possibility of tuning the extract’s characteristics such as mean degree of polymerization and galloylation percentage is explored by means of varying the composition of a quaternary eutectic solvent composed by choline chloride, glycerol, ethanol and water. It was found that mean degree of polymerization values can vary from 6.0 to 7.37 and galloylation percentage can vary from 32.5% to 47.1% while maintaining extraction yield above 72.2 mg of proanthocyanidins per g of biomass. Furthermore, the increase of temperature up to 100 °C has showed a significant effect on the extraction yield being possible to increase it by 238% when compared to the conventional extraction method.

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“…In addition, a significant volume of carbohydrates can increase the viscosity of tannin solutions, which decrease the penetration efficacy of the wood cells (Pizzi 2008, Thévenon et al 2009, Tondi et al 2013. Bianchi et al (2016) have proposed a way to increase the tannin concentration in softwood bark extracts relative to other compounds by inserting a cold-water extraction step before the hot water extractions. They found that phenolic monomers, mono-and oligosaccharides can be almost completely removed during the cold-water extraction.…”

Section: Introductionmentioning

confidence: 99%

“…bark using results from both laboratory and pilot-scale experiments and related previous research. It analyses two approaches to reducing the amount of co-extracts: (a) the introduction of a preliminary cold water step in the extraction process (Bianchi et al 2016); and (b) the use of membrane filtration for separation of the tannin from the non-tannin compounds (Nawas et al 2006). The information provided can help optimize the industrial production procedures and forecast their environmental performance.…”

Section: Introductionmentioning

confidence: 99%

Life cycle assessment of tannin extraction from spruce bark

Ding¹,

Bianchi²,

Ganne-Chédeville³

et al. 2017

iForest

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(1)Tannins have shown antifungal effects and have been considered a potential natural compound for wood preservation. Extracts produced from softwood bark contain both tannins and non-tannin compounds, which may reduce the effectiveness of tannin used as a wood preservative. The purpose of this research is to study the environmental impact of hot water extraction, identify the hot spots within the tannin cradle-to-gate life cycle and give suggestions to optimize its environmental profile. Different extraction and postextraction scenarios of tannin production are compared using the life-cycle assessment method. Experiments were designed to study the tannin yield under different extraction scenarios; the post-extraction scenario analysis was based on literature review. The results show that the extract drying process is the primary contributor to the environmental impact of tannin production. Both preliminary cold water extraction and ultrafiltration after extraction are beneficial as they have fewer non-tannin compounds in the final products; however, preliminary cold water extraction had a considerably lower environmental performance. Successive extractions using fresh water at each cycle increased the total tannin yield, but increased the environmental burden. Using only evaporation to obtain a desired tannin concentration is not environmentally efficient. This paper provides a quantified environmental analysis for the development of tannin-treated wood products and discusses the different tannin extraction scenarios from an environmental point of view.

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Hot water extraction of Norway spruce (Picea abies [Karst.]) bark: analyses of the influence of bark aging and process parameters on the extract composition

Cited by 37 publications

References 44 publications

Fate of Antioxidative Compounds within Bark during Storage: A Case of Norway Spruce Logs

Fate of Antioxidative Compounds within Bark during Storage: A Case of Norway Spruce Logs

Tuning of Proanthocyanidin Extract’s Composition through Quaternary Eutectic Solvents Extraction

Life cycle assessment of tannin extraction from spruce bark

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