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Research Project
EXTRACÇÃO E CARACTERIZAÇÃO ESTRUTURAL DOS CONSTITUINTES DA BANANEIRA DWARF CAVENDISH
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Publications
Surface modification of banana-based lignocellulose fibres
Publication . Cordeiro, Nereida; Oliveira, Lúcia; Faria, Helena; Belgacem, Mohamed Naceur; Moura, João C. V. P.
Lignocellulosic raw materials were isolated from rachis of Musa acuminata Colla var.
cavendish and characterised before and after chemical modification. The rachis was submitted to
different mechanical treatments, milling and defibration, resulting in rachis powder and rachis fi bers, respectively. The chemical composition of these two samples was established and it was
shown that rachis fibres exhibited higher polysaccharide and lignin contents and lower amounts of
ash and extractives components, as compared with the rachis powder. The effects of solvent extrac tion, alkali treatment and chemical modification using phenyl isocyanate, maleic anhydride, alkenyl
succinic anhydride and alkyl ketone dimer as grafting agents were studied. The materials were
characterized in terms of chemical structure by ATR–FT-IR and 13C-CP-MAS-NMR spectroscopy,
morphology by scanning electron microscopy and surface energies by inverse gas chromatography
and contact angle measurements. The surface energy of these materials was found to be very close
to other similar lignocellulosic materials. Finally, the water absorption of these materials before and
after treatment was ascertained. The modified fibres showed considerable changes in ATR–FT-IR
and 13C-CP-MAS-NMR spectra and surface properties, providing very convincing evidence that
chemical grafting had occurred.
Chemical composition of different morphological parts from ‘Dwarf Cavendish’ banana plant and their potential as a non-wood renewable source of natural products
Publication . Oliveira, L.; Cordeiro, N.; Evtuguin, D.V.; Torres, I. C.; Silvestre, A.J.D.
The study on chemical composition and structure of components from different morphological parts of ‘Dwarf Cavendish’ 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 (5–17):(18–54):(35–71). 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.
Lipophilic extractives from different morphological parts of banana plant “Dwarf Cavendish”
Publication . Oliveira, L.; Freire, C.S.R.; Silvestre, A.J.D.; Cordeiro, N.; Torres, I. C.; Evtuguin, D.
The chemical composition of the dichloromethane extracts of different morphological parts of banana plant “Dwarf Cavendish”,
cultivated in Madeira Island (Portugal), were studied by gas chromatography–mass 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 “Dwarf Cavendish”, representing ca. 33–66% and 12–43%, 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.
Steryl glucosides from banana plant Musa acuminata Colla var cavendish
Publication . Oliveira, L.; Freire, C.S.R.; Silvestre, A.J.D.; Cordeiro, N.; Torres, I. C.; Evtuguin, D.
The chemical composition of the dichloromethane extracts of several vegetal fractions of banana plant, Musa acuminata Colla
var cavendish have been studied by GC–MS. 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 838.4–1824.3 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.
Structural characterization of stalk lignin from banana plant
Publication . Oliveira, L.; Evtuguin, D.; Cordeiro, N.; Silvestre, A.J.D.
Dioxane lignins from two fractions of banana plant ‘Dwarf Cavendish’ stalk (floral stalk
(DLFS) and rachis (DLR)) were structurally characterized by a set of spectroscopic (Ultravio let (UV), FTIR, solid- and liquid-state NMR) and chemical degradation (permanganate (PO)
and nitrobenzene oxidation (NO)) techniques. Despite both lignins are of HGS-type, strong
structural differences were observed between them. Thus, DLFS 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 -O-4 structures (0.32/C6 against 0.12/C6)
and the molecular weight (5400 Da against 3750 Da) than those of DLFS. About 72% of the con densed structures in DLFS are of -5 and 5–5 types, whereas 4-O-5
-diaryl ether structures
were the most abundant condensed structures in DLR. 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 fea tures of stalk lignin were discussed in terms of possible restrictions for the kraft pulping of
integral stem material.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
Funding Award Number
SFRH/BD/4749/2001