Browsing by Author "Torres, I. C."
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- Chemical composition and pulping of banana pseudo-stemsPublication . Cordeiro, Nereida; Belgacem, M.N.; Torres, I. C.; Moura, J.C.V.P.This paper deals with the determination of chemical composition and the study of the pulping potentialities of banana pseudo-stems growing in Madeira Island (Portugal). First, the raw material was both studied as a whole (type I) and as the outer bark part (type II), which is richer in cellulose fibres. Before starting the cooking of banana wastes, the main components of the two types of material were quantified, and showed that the polysaccharide content was high enough (about 60–70%) to justify the pulping investigations. Moreover, the lignin content was very low (approximately 12%). The only discouraging finding was the relative high amounts of ashes and extractives. The pulping of these residues was carried out using soda, kraft and soda-anthraquinone (AQ) cooking processes and the optimal pulping conditions were established. Thus, pulps with a yield of about 37–38% with a Kappa number (Kappa no.) about 30–32 were obtained when cooking in the presence of 0.25–0.35% of anthraquinone at 120 ◦C for a short cooking time, i.e. 30 min. The longer times and higher temperatures of cooking as well as the use of kraft pulping conditions did not give rise to better performances, comparing to those mentioned above. These severe conditions were detrimental to the hemicellulose preservation.
- Chemical composition of different morphological parts from ‘Dwarf Cavendish’ banana plant and their potential as a non-wood renewable source of natural productsPublication . 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 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.