22 research outputs found
Chemical composition of different morphological parts from âDwarf Cavendishâ banana plant and their potential as a non-wood renewable source of natural products
The study on chemical composition and structure of components from different morphological parts of âDwarf Cavendishâ banana
plant (petioles/midrib, leaf blades, floral stalk, leaf sheaths and rachis) have been carried out aiming to evaluate their potential as
eventual raw materials for the chemical processing. Macromolecular components were analysed using solid-state NMR, ATR-FTIR
and wet chemistry methods. Mineral components were assessed by ICP analysis of ashes obtained after raw material calcinations.
It was verified that chemical composition of the studied fractions of banana plant varies significantly. The major extremes were
found in the contents of cellulose (37.3% in leaf sheaths and only 15.7% in floral stalk), starch (26.3 in floral stalk and 0.4% in
petioles/midrib), lignin (24.3% in leaf blades and 10.5% in rachis) and lipophilic extractives (5.8% in leaf blades and 1.2% in
petioles/midrib). All morphologic parts of banana plant contained considerable amounts of ashes (from 11.6 to 26.8%) composed
mainly by potassium, calcium and silicium salts. The hemicelluloses in banana plant are proposed to be mainly glucuronoxylan and
xyloglucan (from 5.5% in floral stalk to 21.5% in petioles/midrib). Rather significant amount of proteins was found in leaf blades
(8.3%). Lignin analysis revealed that it is of HGS type with H:G:S proportion ranged of (5â17):(18â54):(35â71). The significant
variation of lignin structure among the different morphological parts of banana plant was highlighted. Results of this study allowed
some propositions about possible applications of banana plant residues as non-wood renewable source of natural products.info:eu-repo/semantics/publishedVersio
Cork suberin as a new source of chemicals.: 1. isolation and chemical characterization of its composition
Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37%
(o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1
H- and 13C-NMR, gas chromatogra phy coupled with mass spectrometric (GCâMS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel
permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half
of the total, were found to be v-hydroxymonocarboxylates, a,v-dicarboxylates, simple alkanoates and 1-alkanols, all with chain
lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by
VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both
fractions constitute interesting precursors for the elaboration of new materials.info:eu-repo/semantics/publishedVersio
Steryl glucosides from banana plant Musa acuminata Colla var cavendish
The chemical composition of the dichloromethane extracts of several vegetal fractions of banana plant, Musa acuminata Colla
var cavendish have been studied by GCâMS. Several bioactive steryl glucosides, namely campesteryl 3- -d-glucopyranoside,
stigmasteryl 3- -d-glucopyranoside and sitosteryl 3- -d-glucopyranoside were identified as the major components of the ex tracts, accounting for 838.4â1824.3 mg/kg of the plant fractions dry weight. The high abundance of these compounds might be
an important contribution to the valorization of banana plant agricultural residues.info:eu-repo/semantics/publishedVersio
Elderberry Stalks as a Source of High-Value Phytochemical: Essential Minerals and Lipophilic Compounds
Elderberry (Sambucus nigra L.) consumption has been growing in the last years, generating a large number of stalks (~10% of the berries bunch) that are still under-valorized. This study focused on the evaluation of elderberry stalks as a source of high-value phytochemicals. In this vein, the essential mineral content and lipophilic composition were analyzed for the first time. In addition, the polar fraction was evaluated regarding its total phenolic content (TPC) and antioxidant activity by both 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assays. The lipophilic fraction was mainly composed of triterpenic acids (2902.20 mg kgâ1 of dry weight (dw)), fatty acids (711.73 mg kgâ1 dw) and sterols (288.56 mg kgâ1 dw). Minor amounts of long-chain aliphatic alcohols and other components were also detected. Ursolic acid (2265.83 mg kgâ1 dw), hexadecanoic acid (219.85 mg kgâ1 dw) and ÎČ-sitosterol (202.74 mg kgâ1 dw) were the major lipophilic components verified. The results of this study also indicated that elderberry stalks might be used as a natural source of essential minerals, particularly calcium, iron and potassium, which are known to play important roles in various body functions. The analysis of the polar fraction also showed that elderberry stalks present TPC as high as elderberry themselves as well as considerable antioxidant activity (1.04 and 0.37 mmol TE gâ1 of extract, against respectively ABTS and DPPH radicals). These results highlight the potential of elderberry stalks as a natural source of high-value phytochemicals that may be explored in several fieldspublishe
Lipophilic extractives from different morphological parts of banana plant âDwarf Cavendishâ
The chemical composition of the dichloromethane extracts of different morphological parts of banana plant âDwarf Cavendishâ,
cultivated in Madeira Island (Portugal), were studied by gas chromatographyâmass spectrometry. The five different morpholog ical fractions in study have a similar qualitative chemical composition. Fatty acids and sterols are the major families present in
the lipophilic extract of âDwarf Cavendishâ, representing ca. 33â66% and 12â43%, respectively, of the total amount of lipophilic
components. Among all the identified compounds, campesterol, stigmasterol, sitosterol and fatty acids, such as palmitic, stearic,
linoleic, linolenic, 22-hydroxydocosanoic, 24-hydroxytetracosanoic and 26-hydroxyhexacosanoic acids, were the major compo nents found in all morphological zones. Other families of compounds, such as aromatic compounds, fatty alcohols and alkanes
were also identified. The high increase of some components after alkaline hydrolysis, particularly, ferulic and fatty acids, indicates
the presence of a considerable fraction of such components in esterified structures.info:eu-repo/semantics/publishedVersio
Oxidized Derivatives of Lipophilic Extractives Formed during Hardwood Kraft Pulp Bleaching
Easily Degradable Chlorinated Compounds Derived from Glucuronoxylan in Filtrates from Chlorine Dioxide Bleaching of Eucalyptus globulus Kraft Pulp
Structural characterization of stalk lignin from banana plant
Dioxane lignins from two fractions of banana plant 'Dwarf Cavendish' stalk (floral stalk (DL(FS)) and rachis (DL(R))) were structurally characterized by a set of spectroscopic (Ultraviolet (UV), FTIR, solid- and liquid-state NMR) and chemical degradation (permanganate (PC) and nitrobenzene oxidation (NO)) techniques. Despite both lignins are of HGS-type, strong structural differences were observed between them. Thus, DL(FS) showed almost twice the abundance of H and G units and almost half of the abundance of S units when compared to DLR. DLR possessed significantly higher amount of beta-O-4' structures (0.32/C(6) against 0.12/C(6)) and the molecular weight (5400 Da against 3750 Da) than those of DL(FS). About 72% of the condensed structures in DL(FS) are of beta-5 and 5-5' types, whereas 4-O-5'-diaryl ether structures were the most abundant condensed structures in DL(R). Most of H units in both lignins are terminal phenolic coumarates linked to lignin substructures by ester bonds. Both lignins are structurally associated with suberin-like components in cell wall tissues. Structural features of stalk lignin were discussed in terms of possible restrictions for the kraft pulping of integral stem material. (C) 2008 Elsevier B.V. All rights reserved.FCT - BD/4749/200
Nanocellulose fibers and other natural polymers as unique pieces for the development of sustainable composites: A [email protected]
cited By 0International audienceIn recent years we have been engaged on the development of novel (nano)composite materials based on nanocellulose forms and other natural polymers, following different strategies, including heterogeneous chemical modification and compounding with thermoplastic matrices, combination with other natural polymers like chitosan and starch and blending with other materials. A global overview of the research activities developed in these domains in our group will be presented and discussed in this communication