The effect of thermal drying on the contents of condensed tannins and stilbenes in Norway spruce (Picea abies [L.] Karst.) sawmill bark

Jylhä, Paula; Halmemies, Eelis; Hellström, Jarkko; Hujala, Maija; Kilpeläinen, Petri; Brännström, Hanna

doi:10.1016/j.indcrop.2021.114090

Cited by 10 publications

(13 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25%, whereas the condensed tannins content was reduced from ca. 35 mg•g −1 to 23 mg•g −1 [32]. A similar study on willow bark concluded that drying at 70 • C in a tray did not cause significant changes neither in the phenol nor in the flavonoids or the tannin contents [33].…”

Section: Resultsmentioning

confidence: 87%

Extraction of Phenolic Compounds from Populus Salicaceae Bark

et al. 2022

View full text Add to dashboard Cite

Lignocellulosic residues have the potential for obtaining high value-added products that could be better valorized if biorefinery strategies are adopted. The debarking of short-rotation crops yields important amounts of residues that are currently underexploited as low-grade fuel and could be a renewable source of phenolic compounds and other important phytochemicals. The isolation of these compounds can be carried out by different methods, but for attaining an integral valorization of barks, a preliminary extraction step for phytochemicals should be included. Using optimized extraction methods based on Soxhlet extraction can be effective for the isolation of phenolic compounds with antioxidant properties. In this study, poplar bark (Populus salicaceae) was used to obtain a series of extracts using five different solvents in a sequential extraction of 24 h each in a Soxhlet extractor. Selected solvents were put in contact with the bark sample raffinate following an increasing order of polarity: n-hexane, dichloromethane, ethyl acetate, methanol, and water. The oily residues of the extracts obtained after each extraction were further subjected to flash chromatography, and the fractions obtained were characterized by gas chromatography coupled with mass spectrometry (GC–MS). The total phenolic content (TPC) was determined using the Folin–Ciocalteu method, and the antioxidant activity (AOA) of the samples was evaluated in their reaction with the free radical 2,2-Diphenyl-picrylhydrazyl (DPPH method). Polar solvents allowed for higher individual extraction yields, with overall extraction yields at around 23% (dry, ash-free basis). Different compounds were identified, including hydrolyzable tannins, phenolic monomers such as catechol and vanillin, pentoses and hexoses, and other organic compounds such as long-chain alkanes, alcohols, and carboxylic acids, among others. An excellent correlation was found between TPC and antioxidant activity for the samples analyzed. The fractions obtained using methanol showed the highest phenolic content (608 μg of gallic acid equivalent (GAE)/mg) and the greatest antioxidant activity.

show abstract

Section: Resultsmentioning

confidence: 87%

Extraction of Phenolic Compounds from Populus Salicaceae Bark

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Polyphenolic compounds, such as stilbenes, lignans, and tannins, are more difficult to process than fatty acids and resin acids, being either dissolving or non-dissolving, often unstable, and challenging in chemical modification [33,37,58]. In addition to resin acids and sterols, stilbenes, lignans, and flavonoids are the main extractive compounds of Scots pine which provide bioactive benefits based on antioxidative, antifungal, and antibacterial properties [5,21,36].…”

Section: Discussionmentioning

confidence: 99%

“…Tree biomass components that are rich in stilbenes or lignans have been proposed for industrial utilization for a wide variety of preservatives due to their antioxidative, antifungal, and antibacterial properties [5,16,21,36]. Stilbenes of pine species have been introduced as effective agents in wood treatment and processing, but they have so far been used only in a limited scale (surface treatment, impregnation, gluing) [15,16,36,37]. Lignans are already in use for medical purposes, such as cancer treatments, weight control and prevention of cardiological diseases [15,16,38].…”

Section: Introductionmentioning

confidence: 99%

Extractives of Tree Biomass of Scots Pine (Pinus sylvestris L.) for Biorefining in Four Climatic Regions in Finland—Lipophilic Compounds, Stilbenes, and Lignans

Verkasalo

Roitto

Möttönen

et al. 2022

Forests

Self Cite

View full text Add to dashboard Cite

The aim of the study was to quantify total extractive contents and lipophilic compounds, stilbenes, and lignans in Scots pine stem wood, stem bark, branch biomass, and sawmill residues in four climatic regions of Finland to evaluate the most optimal sources of extractives for bio-based chemical biorefining and bioenergy products. Data were derived from 78 chip samples from the before-mentioned raw materials, the samples being pooled by tree height position from the sample trees of 42 experimental forest stands, and sawdust lots from 10 log stands. Accelerated solvent extraction (ASE) was employed to determine total extractive contents, followed by gas chromatography with flame ionization detection (GC–FID) to quantify extractive groups and gas chromatography-mass spectrometry (GC–MS) to analyse individual extractive compounds. Resin acids and triglycerides followed by fatty acids were the dominant extractive groups. Resin acids were most abundant in stem wood from final fellings and in sawdust, fatty acids in bark and branch biomass, and triglycerides also in stem wood from thinnings and the top parts of trees. Of the minor extractive groups, stilbenes were the most abundant in stem wood from final fellings and in sawdust, and steryl esters, sterols, and lignans in bark and branch biomass, the two last groups almost missing from other biomass components. Regional differences in the contents of extractive groups were generally small, 1.0−1.5 percentage points at the maximum, but factor analysis distinguished northern and southern regions into their own groups. Bark was the most potential source of fatty acids and sterols in southern Finland, and triglycerides and steryl esters in northern Finland. In stem wood, steryl esters, triglycerides, and lignans decreased and stilbenes increased from north to south. Certain fatty acids and resin acids were more frequent in the north. The results highlighted the importance of focused procurement and efficient sorting of raw materials, purity, unique properties, and feasible isolation techniques for competitive ability as well as large raw material volumes or well-defined value-added products.

show abstract

“…It was also verified that the stilbenes content decreased (36-43%) after 10 h, with losses up to 60% recorded through the drying process. Although thermal drying at 50 • C was considered as a moderate and optimized drying temperature, the authors concluded that it is not an efficient industrial process due to significant loss of chemical components (Jylhä et al, 2021). It must be noted that the heat and mass transfer can be evaluated by equation presented in Sections 2.1 and 2.2.…”

Section: 31mentioning

confidence: 99%

Emerging drying techniques for food safety and quality: A review

Fathi

Ebrahimi

Matos

et al. 2022

Comp Rev Food Sci Food Safe

View full text Add to dashboard Cite

The new trends in drying technology seek a promising alternative to synthetic preservatives to improve the shelf‐life and storage stability of food products. On the other hand, the drying process can result in deformation and degradation of phytoconstituents due to their thermal sensitivity. The main purpose of this review is to give a general overview of common drying techniques with special attention to food industrial applications, focusing on recent advances to maintain the features of the active phytoconstituents and nutrients, and improve their release and storage stability. Furthermore, a drying technique that extends the shelf‐life of food products by reducing trapped water, will negatively affect the spoilage of microorganisms and enzymes that are responsible for undesired chemical composition changes, but can protect beneficial microorganisms like probiotics. This paper also explores recent efficient improvements in drying technologies that produce high‐quality and low‐cost final products compared to conventional methods. However, despite the recent advances in drying technologies, hybrid drying (a combination of different drying techniques) and spray drying (drying with the help of encapsulation methods) are still promising techniques in food industries. In conclusion, spray drying encapsulation can improve the morphology and texture of dry materials, preserve natural components for a long time, and increase storage times (shelf‐life). Optimizing a drying technique and using a suitable drying agent should also be a promising solution to preserve probiotic bacteria and antimicrobial compounds.

show abstract

The effect of thermal drying on the contents of condensed tannins and stilbenes in Norway spruce (Picea abies [L.] Karst.) sawmill bark

Cited by 10 publications

References 33 publications

Extraction of Phenolic Compounds from Populus Salicaceae Bark

Extraction of Phenolic Compounds from Populus Salicaceae Bark

Extractives of Tree Biomass of Scots Pine (Pinus sylvestris L.) for Biorefining in Four Climatic Regions in Finland—Lipophilic Compounds, Stilbenes, and Lignans

Emerging drying techniques for food safety and quality: A review

Contact Info

Product

Resources

About