The COVAPAM laboratory published for its study on adding value to the fruit of the Moucaya palm tree

L he Amazon is home to a wide variety of palm trees (18 genera in French Guiana), distributed across different habitats (mangrove, pinnotere, shallows, terra firma, white sand, etc.) characterised by unique environmental conditions. Traditionally, palm trees have been used to meet the essential needs of local populations, such as the construction of homes and the production of fuels, waxes and fibres. They are also used in various fields such as agri-food, cosmetics and traditional medicine, making a significant contribution to economic development thanks to their diverse phytochemical composition.

However, despite their importance, the phytochemical composition of palm trees in French Guiana, with the notable exception of Euterpe oleraceae (Açai or wassaye), remains largely unknown. The species Acrocomia aculeata, in particular, has interesting similarities with olive oil in terms of its fatty acid composition, suggesting a high potential for use in the agri-food sector. Research has also revealed the presence of atypical glucomannans in the fruits of this palm, opening the way to new applications. By exploiting this resource in a sustainable way, it is possible to contribute to economic diversification while preserving the natural wealth of the Amazon.

Acrocomia aculeata: a species with multiple properties

The fruit of the Acrocomia aculeata palm is rich in polyunsaturated oils, including oleic acid (9), linoleic acid (6) and linolenic acid (3). This composition has led to the use of the oil extracted from this fruit as a source of energy for biofuels, particularly in Brazil, where its production is subject to controls. This growing demand stimulated the setting up in 2004 of a chain between industrialists for the production of biodiesel and farmers for the cultivation of these palm trees.

However, few studies have been devoted to the development of Acrocomia aculeata in French Guiana. Part of Wilfried Denagbe's thesis work, supervised by Thierry Benvegnu (University Professor of Chemistry), Didier Bereau (HDR, University Professor of Chemistry), Jean Charles Robinson (University Professor of Biochemistry) and Rudy Covis (Senior Lecturer in Chemistry), enabled us to gain a deeper understanding of the subject. This work has made it possible to develop and optimise methods for extracting the carbohydrates present in the fruit pulp (mesocarp), and to elucidate the chemical structure of atypical glucomannans (oligo/polysaccharides) using nuclear magnetic resonance spectrometry.

These studies have contributed to a deeper scientific understanding of the fruits of this palm tree, which is found all along the Guiana coast. The physicochemical properties of the atypical glucommanans present in the fruits were highlighted, in particular their capacity to swell, their rheological behaviour and their surface-active properties. In addition, the possibility of functionalizing glucommanans by esterification was explored and the ability of these amphiphilic polysaccharides to form nanovectors by self-assembly was characterized using dynamic light scattering and microscopy techniques. In this way, we demonstrated their potential for encapsulating a lipophilic fluorescent probe and monitored the stability of these nano-objects over time for the controlled release of biologically active molecules.

Finally, this work led to the publication of a scientific article accepted on 17 October 2023 and published on 19 October 2023 in the journal Carbohydrate polymers, IF 11,2) entitled "Structure and emulsifying properties of unprecedented glucomannan oligo- and polysaccharides from Amazonia Acrocomia aculeata palm fruit", produced in collaboration between the COVAPAM laboratory and the organic chemistry and interface laboratory (CORINT) at the Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), which develops raw materials of natural origin for health applications.