Browsing by Author "Evtuguin, D."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- 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.
- Products of the permanganate oxidation of Cork, desuberized Cork, suberin and lignin from Quercus suber L.Publication . Lopes, M.; Neto, C. Pascoal; Evtuguin, D.; Silvestre, A. J. D.; Gil, A.; Cordeiro, N.; Gandini, A.
- Steryl glucosides from banana plant Musa acuminata Colla var cavendishPublication . 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 plantPublication . 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.