Eucalyptus urophylla hybrids are important raw materials for the forest industry in Brazil, and large quantities of barks are available at mill site that may be used for added-value products. The chemical composition of barks of six commercial hybrids clones of E. urophylla × E. grandis, E. urophylla × E. Camaldulensis, and undisclosed E. urophylla hybrids was studied. The hybrids had similar composition, on average (data based on oven dry bark): 16% extractives, mainly corresponding to polar compounds that are soluble in ethanol and water, 19% lignin, 47% polysaccharides, 1% suberin, and 2% ash. The polysaccharides consists mainly of cellulose as indicated by 84% of total neutral monosaccharides in the acid hydrolysate and 10% xylose. The compositions of the lipophilic extracts was determined by GC-MS before and after alkaline hydrolysis. In all the barks, fatty acids, and triterpenes (namely: betulinic and ursolic acids) were the most abundant compounds followed by smaller amounts of sterols, long-chain aliphatic alcohols, phenolic acids, and acylglycerols. The ethanol-water bark extract had a high phenolic content: total phenolics ranged 211-551 mg gallic acid equivalents (GAE) g -1 of extract, tannins 76-184 mg catechin equivalents (CE) g -1 extract, and flavonoids 98-234 mg CE g -1 of extract. The antioxidant activity corresponds to 338 mg Trolox g -1 of extract. Development of high-value products is proposed through an integrated biorefinery approach including valorisation of extractives and targeting for cellulose-based applications.
The bark of Anadenanthera peregrina (L.) Speg and Anadenanthera colubrina (Vell.) Brenan were characterized in relation to anatomical and chemical features. The barks were similar and included a thin conducting phloem, a largely dilated and sclerified non-conducting phloem, and a rhyridome with periderms with thin phellem interspersed by cortical tissues. Only small differences between species were observed that cannot be used alone for taxonomic purposes. The summative chemical composition of A. peregrina and A. colubrina was respectively: 8.2% and 7.7% ash; 28.8% and 29.3% extractives; 2.4% and 2.6% suberin; and 18.9% lignin. The monosaccharide composition showed the predominance of glucose (on average 82% of total neutral sugars) and of xylose (9%). The ethanol-water extracts of A. peregrina and A. colubrina barks included a high content of phenolics, respectively: total phenolics 583 and 682 mg GAE/g extract; 148 and 445 mg CE/g extract; tannins 587 and 98 mg CE/g extract. The antioxidant activity was 238 and 269 mg Trolox/g extract. The barks of the Anadenanthera species are a potential source of polar extractives that will represent an important valorization and therefore contribute to improve the overall economic potential and sustainability of A. peregrina and A. colubrina
RESUMOEste trabalho teve como objetivo quantificar fenóis totais e taninos nas cascas de angicovermelho (Anadenanthera peregrina) em diferentes classes de diâmetro, além de comparar duas metodologias de quantificação de fenóis. Foram coletadas cascas de 35 árvores, distribuídas em sete classes diamétricas. As cascas foram secas ao ar livre, trituradas e peneiradas, sendo utilizado o material retido na peneira de 60 mesh. Para a extração dos fenóis, utilizou-se metanol:água (50%). O doseamento de fenóis totais foi realizado pelos métodos de Folin-Denis e Folin-Ciocalteau modificados, e para taninos, pelo método difusão radial. Não foi encontrada diferença estatística entre as metodologias de quantificação de fenóis. Verificou-se aumento nos teores de fenóis e taninos com o aumento do diâmetro das árvores.Palavras-chave: cascas, fenóis, taninos.
RESUMO:O objetivo deste trabalho foi determinar o rendimento gravimétrico em taninos condensados nas cascas de Anadenanthera peregrina em diferentes classes diamétricas. Coletaram-se amostras de cinquenta e nove árvores de Anadenanthera peregrina, a 1,30 m do solo (Diâmetro a altura do peito -DAP), distribuídas em sete classes diamétricas. As cascas foram secas ao ar e trituradas em moinho de martelo. Foram realizadas amostragem composta para o preparo do extrato. A extração foi feita em água, na relação 15:1 (v/p), adicionados 3% de sulfito de sódio (v/v) em banho-maria a 70ºC por 4 horas. O material foi filtrado com emprego de coador de pano fino e concentrado em chapa de aquecimento a aproximadamente 150 g. Foi determinada a massa do extrato e retirados 10 g para a obtenção do teor de sólidos e 20g para a para o índice de Stiasny. Os valores médios de teor de sólidos totais, índice de Stiasny, teor de tanino condensado e teor de compostos não tânicos foram de 11,34%; 75,79%; 12,76% e 4,07%, respectivamente. O teor de sólidos, índice de Stiasny, teor de compostos não tânicos tiveram diferenças significativas entre as classes diamétricas. Já para a produção de taninos condensados, o parâmetro classe diamétrica não influenciou.Palavras-chave: Angico-vermelho, índice de Stiasny, compostos fenólicos, adesivo natural. TANNINS GRAVIMETRIC YIELD CONDENSED IN Anadenanthera peregrina BARK IN DIFFERENT DIAMETER CLASSES ABSTRACT: This work aimed to determine the gravimetric yield of condensed tannins in the Anadenanthera
Aim of the study was to estimate the influence of the fiber length and basic density on microfibril angle of Eucalyptus microcorys wood. The study area was in an experimental planting at the Universidade Federal de Lavras, Minas Gerais State, Brazil. Three 37 year-old Eucalyptus microcorys trees were used, from whose stems six centimeter-thick discs were removed, cut at a high of three meters. The disks were sanded and planed to highlight the growth rings. Specimens were taken every 1,5 cm across the radius from pith to bark for determining microfibril angle, fiber length and wood basic density. The microfibril angles were determined by use of polarized light microscopy, while the fiber morphology and basic density were determined by usual methods. The averages found for microfibril angle (12,6°), fiber length (968 µm) and basic density (480 kg.m-3) are, in general, within the range of values reported for these characteristics of wood. The microfibril angle showed accentuated reduction of the average values in the pith-bark direction. The fiber length and basic density showed the opposite behavior. We observed that the density and fiber length may be used as a microfibril angle predictor, accounting for 96% and 79% of its variation, respectively.
Barks from two commercial clones of Eucalyptus urophylla hybrids used by the charcoal industry in Brazil were analyzed, with their polar extracts characterized. Also, tannins were extracted with water and sodium sulfite. The mean bark chemical composition showed 2.6% ash, 16% extractives (89% of which were polar extractives), 1.2% suberin, 18.9% lignin, and 61.4% polysaccharides composed mainly of glucans (glucose 48.3% of bark) and xylans (xylose plus arabinose 10.1% of bark). The polar extracts included high mean contents of total phenolics (380.9 mg GAE / g extract), flavonoids (178.4 mg CE / g extract), and tannins (67.7 mg CE / g extract). The mean antioxidant activity of the extracts was low (53.6 mg Trolox / g of bark extract). The extracts had Stiasny indices of 20% with water and 45% with sodium sulfite solution. The FTIR spectra showed condensed tannin bands characteristic of C=C, C-C, and O-H bonds. The barks of E. urophylla hybrids are a potential source of polar extractives that may represent an important valorization.
IInvestigações científicas sobre a morfometria de árvores subsidiam o planejamento e gerenciamento racionais da arborização urbana, importante para a sustentabilidade ambiental de cidades. O objetivo foi avaliar a eficiência da modelagem de relações morfométricas interdimensionais da copa de L. tomentosa empregando regressão logística e Máquinas Vetor de Suporte (MVS), identificando potenciais usos no planejamento da arborização urbana. O inventário foi conduzido nos municípios de São João Evangelista e Peçanha em Minas Gerais. Foram amostradas 116 árvores em 21 vias públicas. Calcularam-se o formal de copa, índice de saliência, índice de abrangência, grau de esbeltez, proporção de copa e área de projeção de copa. Foram testados dois métodos de modelagem para a estimativa de altura total, altura de inserção da copa e índices morfométricos de copa (r, p ≤ 0,01) em função exclusivamente do DAP, uma por regressão não linear (modelo logístico) e outra por MVS. A altura total, altura de inserção da copa, formal de copa, índice de abrangência e área de projeção de copa aumentaram à medida que fustes se tornaram mais grossos. O decrescimento com o aumento do DAP foi observado somente para o grau de esbeltez. Relações morfométricas podem ser estimadas com precisão por modelos de regressão e MVS. Informações da média assintótica do estoque de crescimento de L. tomentosa em altura total, altura de inserção da copa, área de projeção da copa e raio de copa são úteis para a definição do local de seu plantio em áreas urbanas, indicado para praças, canteiros e/ou calçadões.
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