Characterization of Crude and Processed Pulp Cell Walls of Three Selected Mamey Accessions (Mammea americana L.).

Mamey (Mammea americana L.) is a tropical fleshy fruit native from the West Indies and northern South America. It is very appreciated for its flavor and color but has been little described. The present study investigates the composition and histochemistry of the pulp cell walls of three mamey accessions readily available in Martinique. The impact of pulp processing into puree on cell wall composition is evaluated. The histology and rheology of mamey puree are assessed considering these characterizations. Mamey pulp cell wall composition is dominated by highly methyl-esterified pectins (DM: 66.2-76.7%) of high molecular weight, and show few hemicelluloses, mainly xyloglucans. Processing reduced methyl-esterified uronic acid contents and gave purees with significantly different viscosities. Mamey puree was composed of polydisperse particles (20-2343 µm), which size distributions were different depending on the accession: Ti Jacques was dominated by smaller particles (50% had approximated diameters lower than 160 µm), Sonson's by larger particles (50% had approximated diameters higher than 900 µm), and Galion's had an intermediate profile. This new knowledge on mamey pulp is valuable for future works on mamey processing into new food products, even more so for those including cell wall polysaccharide-degrading enzymes.

Electrophoretic separation of gill proteins of the clam Codakia orbicularis.

Marine organisms inhabiting the coastal environment of the Caribbean islands have attracted the attention of a number of research scientists. These organisms generally live in areas of high environmental stress and may, therefore, contain specialized proteins and enzymes which exhibit valuable biotechnological applications. Among them, a small number of clams have been studied. Our work relates to the clam Codakia orbicularis. This bivalve lives in areas of high hydrogen sulfide concentrations on the Caribbean island of Guadeloupe. Its enzymatic system must, therefore, have evolved to allow its adaptation to this high-stress environment. C. orbicularis also contains endosymbiotic bacteria which are housed in the bacteriocytes of the gills. Its protein content can, therefore, be expected to have an impact on this symbiotic relationship. We have analysed gill protein extracts of this clam by various biochemical techniques: SDS-PAGE, IEF, PAS, and Western blotting using a panel of lectins, in order to establish its protein and glycoprotein profiles. This biochemical analysis, the first of its kind, constitutes an important step in separating and characterizing the proteins involved in the biochemical pathways of this organism whose stock is in decline in Guadeloupe. Our results show the presence of three major proteins whose molecular weights vary between 14,000 and 24,000 Daltons, and some of which are glycoproteins with predominantly alpha-mannose and N-acetylgalactosamine moieties. Their pI values are in the range between 4.5 and 5.6. These protein profiles are different from those observed for Lucina pectinata, a clam which has been the subject of earlier studies in the literature.