INVESTIGADORES
PONCE Nora Marta Andrea
artículos
Título:
Changes on the cell wall composition of tree-ripened “Bartlett” pears (Pyrus communis L.)
Autor/es:
MARÍA D. RAFFO; NORA M.A. PONCE; GABRIEL O. SOZZI; CARLOS A. STORTZ; ARIEL R. VICENTE
Revista:
POSTHARVEST BIOLOGY AND TECHNOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 73 p. 72 - 79
ISSN:
0925-5214
Resumen:
Most of the European pear cultivars fail to develop a desirable texture when ripening on the tree. Inorder to identify some biochemical anomalies that might be associated with this phenomenon, the maindifferences in cell wall polysaccharides occurring during “Bartlett” pear on-tree ripening were evaluated.Fruit was harvested at 3 different ripening stages (119, 147 and 161 days after anthesis, DAA) namelyunripe (UR) mid-ripe (MR) both developing normal texture upon ripening, and late-ripe (LR), which didnot result in buttery and juicy fruit. The characterization of cell wall structure was accomplished bydetermining the monosaccharide composition, yields, and solubility of uronic acids and neutral sugarsin fractions extracted by water (WSF), 0.05 M CDTA (CSF), 0.1 M Na2CO3 (NSF), 1 M and 4 M KOH (1KSFand 4KSF). The size exclusion profiles in all the isolated fractions were also determined. In the transitionfrom the UR to the MR stage, glucose from the 4KSF and Ara from all other fractions became markedlysolubilized. A slight increase in water-soluble pectin content and depolymerization of the 4KSF andCSF were also found during this period. From the MR to the LR stage, a glucan probably originating incellulose turnover was found in the 4KSF, and (though at a lower rate) Ara solubilization continued. Incontrast, the depolymerization of all wall fractions after day 147 was minimal, and a shift of water solublepectins toward the CSF was detected. An imbalance in polyuronide degradation, including decreaseddepolymerization of pectin backbones, together with continuing removal of Ara from RG I, and/or othermodifications increasing ionic interactions, may lead fruit which yield an abnormal, mealy texture uponripening.