The use of non-isobaric pre-hydrolysis for the isolation of organic compounds from wood and bark

Кузнецов, Б. Н.; Efremov, A. A.; Levdanskii, V. A.; Кузнецова, Светлана А.; Polezhayeva, N.I.; Shilkina, T.A.; Krotova, I. V.

doi:10.1016/s0960-8524(96)00097-1

Cited by 16 publications

(8 citation statements)

References 5 publications

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“…The Klason lignin content in the solid phase decreases with increasing severity up to a severity value, which is dependent on the raw material. High severity conditions resulted in increased proportions of Klason lignin in solids, because condensation and repolymerization reactions led to the formation of pseudo‐lignin from hemicellulose degradation products and lignin fragments (Kuznetsov et al. 1996).…”

Section: Resultsmentioning

confidence: 99%

Antioxidant Activity of Fractions From Acid Hydrolysates of Almond Shells

Moure

Domı́nguez

Parajó

2008

J Food Process Engineering

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Acid hydrolysis of almond shells was carried out with 2.5 and 5% sulfuric acid, and the ethyl acetate soluble fraction of hydrolysates (EASH) was fractionated on a Sephadex Uppsala, Sweden) column. Three fractions were recovered from the crude extract produced by hydrolysis with 2.5% sulfuric acid (EASH-2.5), and five from the one produced with 5% sulfuric acid . The recovered fractions were assayed for phenolic content, radical-scavenging activity (measured by the a,a-diphenylb-picrylhydrazyl and Trolox equivalent antioxidant capacity [TEAC] methods) and reducing capacity (measured by the ferric-reducing antioxidant power [FRAP] and the reducing power methods). The highest contents of phenolics corresponded to the third fraction (F3) from EASH-2.5 and to the fourth fraction (FЈ4) from EASH-5, whereas fraction 1 (F1) from EASH-2.5 and fraction 4 from EASH-5 showed the highest TEAC and FRAP values, and reducing power. PRACTICAL APPLICATIONSAcid-catalyzed hydrolysis for producing xylose is the most common technology for processing almond shells into chemicals, and allows fractionation of this residue into a solid fraction (cellulose and lignin) and a liquid stream containing monomeric sugars, sugar degradation products, extractives and lignin depolymerization compounds. To destine the monomeric sugars as a carbon source for bioconversion purposes, a detoxification step is required. Solvent extraction with ethyl acetate yields a by-product fraction consisting of compounds with phenolic nature and antioxidant activity, and its utilization 1 Corresponding

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Section: Resultsmentioning

confidence: 99%

Antioxidant Activity of Fractions From Acid Hydrolysates of Almond Shells

Moure

Domı́nguez

Parajó

2008

J Food Process Engineering

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“…They constitute a very small percentage of the total fraction isolated with ethyl acetate, ranging between 3.52 and 8.56%. This is probably due to the fact that ethyl acetate extracts, in addition to those monomeric compounds identified, a series of oligomeric substances from lignin (20), and other condensation and degradation products derived from hemicelluloses (21,22).…”

Section: Resultsmentioning

confidence: 99%

Hydroxytyrosol and tyrosol as the main compounds found in the phenolic fraction of steam‐exploded olive stones

Fernández‐Bolaños

Felizón

Brenes

et al. 1998

J Americ Oil Chem Soc

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The lignocellulosic by-products, whole stones, and seed husks obtained from processing pitted table olives and oil olives were pretreated under various conditions of steam explosion, with and without previous acid impregnation. The various water-soluble noncarbohydrate compounds generated during steam explosion, such as sugar degradation compounds (furfural and hydroxymethylfurfural), lignin degradation compounds (vanillic acid, syringic acid, vanillin, and syringaldehyde) and the simple phenolic compounds characteristic of olive fruit (tyrosol and hydroxytyrosol), were identified. The amount of hydroxytyrosol solubilized was higher than that of the other compounds, and increased with increasing steaming temperature and time. This suggests its presence as a structural component of the olive stone.Olive stones have a high content of lignocellulosic material and are an important by-product of table olive processing. Pitted table olives make up 70-75% of total table olive production (1). The olive pomace obtained from olive fruit processing contains seed husk and a small amount of seeds, pulp, and peel, which can be separated by common industrial methods.Research related to oil, proteins, sugars, and phenolic compounds of olive seed has been carried out (2-5), but information related to the seed husk is scarce. However, the fiber of olive seed husks has been studied (6), and its polysaccharides have been characterized (7).The lignocellulosic products are currently used as an energy source, and have recently been employed to produce activated carbon (8). Steam explosion treatment (explosive autohydrolysis) has been extensively studied as a promising pretreatment process (9,10) to separate and increase the accessibility of main components of lignocellulosic biomass (cellulose, hemicellulose, and lignin). During steam explosion, the lignocellulosic material is split, and lignin is partly depolymerized (11), giving rise to phenolic compounds which are water-soluble and have inhibitory action against microorganisms (12,13).Olive leaves and fruit contain a considerable amount of phenolic compounds, mainly oleuropein, which, apart from their inhibitory action against microorganisms (14), have an antioxidant effect on the oxidative stability of oils (15). Some of these phenolic compounds are contained in the olive fruit processing by-products.In this study, the simple phenolic compounds obtained from the steam explosion of whole stones and seed husks were characterized and quantified, and the effect of temperature and time during steam explosion on the yield of these phenolic substances was evaluated. EXPERIMENTAL PROCEDURESMaterials. Whole olive stones were obtained from pitted table olives dried in an air stove at 30ºC and rubbed vigorously on a filter paper to remove any loosely adhering pulp tissue. Olive seed husks were supplied by an oil extraction plant (Oleícola el Tejar, Córdoba, Spain). The husks were obtained from olive pomace after separating peel, pulp, and seeds.Steam treatment. The steam explosion treatments ...

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“…Organic matter and microbial biomass Working on the same experimental plots used in these studies, Peres et al (1998) found that organic enrichment by PB and CB mulching increased earthworm abundance and fostered good burrowing activity, which improved organic C incorporation into the soil. Our results showed that microbial biomass C was greater in soils with grass cover than in soils amended with tree barks (PB and CB), probably because the barks consisted mainly of macromolecules resistant to biodegradation by microorganisms, such as cellulose, hemicellulose and lignin (Kuznetsov et al 1996;Mathers et al 2002), whereas grass root exudates, dead grass leaves and root biomass were richer in proteins and polysaccharides (Haynes & Beare 1997;Oyedele et al 1999), which are more easily degraded. In 2000, differences between treatments used to discriminate the effects of vineyard management on the pools of organic matter were greater in the 0 -5 cm layer than in the 0 -20 cm layer.…”

Section: Discussionmentioning

confidence: 64%

“…Comparison of the aggregate stability in water under CB and PB sampled in 1997 and 2000 further illustrates the effect of different types of organic matter on aggregate stability. Coniferous bark is richer in humified organic matter, such as lignin, than poplar bark (Kuznetsov et al 1996). The greater C/N ratio values of the CB (36 to 124 depending on the year) compared with those of the PB (28 to 59) may indicate the higher degree of humification of the organic matter originating from the CB (Table 4).…”

Section: Aggregate Stabilitymentioning

confidence: 99%

Water-stable aggregates and organic matter pools in a calcareous vineyard soil under four soil-surface management systems

Goulet¹,

Dousset²,

Chaussod³

et al. 2004

soil use manage

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Vineyards in Champagne, France are generally situated on slopes where the soils are subject to erosion. Therefore it is important to find a soil-surface management practice that protects the soil against water erosion. We assessed the potential of mulches or grass covers to stabilize soil aggregates in a calcareous sandy loam from a vineyard in Champagne after 9 years under different management systems. Four different treatments were studied: (i) a bluegrass (Poa pratensis) surface cover between the vine rows (GC) with bare soil under the vines (R); two organic mulches of (ii) coniferous (CB) or (iii) poplar (PB) bark that covered the entire soil surface, and (iv) bare soil between the rows as a control. The bark amendments were applied every 3 years at rates of 61 and 67 t ha 21 for the PB and CB treatments, respectively. The kinetics of soil disaggregation in water fitted a power law (A ¼ K t 2D ), in which K was the fraction of water-stable .200 mm aggregates remaining after 1 hour of wet-sieving. In the 0 -5 cm layer, aggregate stability was greater for GC (K ¼ 21.7), CB (K ¼ 15.2) and PB (K ¼ 13.6) than for the control (K ¼ 10.5) and R (K ¼ 11.8). In the 0 -20 cm layer, CB also stabilized soil aggregates (K ¼ 14.0 -15.0); but PB did not. Structural stability was more strongly related to total organic carbon (R 2 ¼ 0.64, P , 0.001) than to microbial biomass carbon (R 2 ¼ 0.54, P , 0.001). A bluegrass cover enhanced structural stability in the 0 -5 cm and 0 -20 cm layers (K ¼ 14.2), probably because of intense root development and rhizodeposition enhancing microbially produced metabolites, such as carbohydrates. Establishing grass cover or applying bark mulch are effective agricultural practices that improve soil aggregate stability and thus should reduce soil erosion. The vegetative growth of the vines was greater on the soils amended with bark mulches and less on the grass covered soils compared with the control soil; however, no difference in wine quality was observed among the different treatments.

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The use of non-isobaric pre-hydrolysis for the isolation of organic compounds from wood and bark

Cited by 16 publications

References 5 publications

Antioxidant Activity of Fractions From Acid Hydrolysates of Almond Shells

Antioxidant Activity of Fractions From Acid Hydrolysates of Almond Shells

Hydroxytyrosol and tyrosol as the main compounds found in the phenolic fraction of steam‐exploded olive stones

Water-stable aggregates and organic matter pools in a calcareous vineyard soil under four soil-surface management systems

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