Changes in Cell Wall Composition Associated to the Softening of Ripening Papaya: Evidence of Extensive Solubilization of Large Molecular Mass Galactouronides

Autor(es)

Shiga, Tania Misuzu ^[1] ; Fabi, Joao Paulo ^[1] ; Oliveira do Nascimento, Joao Roberto ^[1] ; de Oliveira Petkowicz, Carmen Lucia ^[2] ; Vriesmann, Lucia Cristina ^[2] ; Lajolo, Franco Maria ^[1] ; Cordenunsi, Beatriz Rosana ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Lab Quim Bioquim & Biol Mol Alimentos, Dept Alimentos & Nutr Expt, FCF, BR-05508900 Sao Paulo - Brazil

^[2] Univ Fed Parana, Lab Quim Carboidratos Vegetais, Dept Bioquim & Biol Mol, BR-81531990 Curitiba, Parana - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Agricultural and Food Chemistry; v. 57, n. 15, p. 7064-7071, AUG 12 2009.
• Citações Web of Science: 31

Resumo

Papaya (Carica papaya) is a climacteric fruit that undergoes dramatic pulp softening. Fruits sampled at three different conditions (natural ripening or after exposition to ethylene or 1-methylcyclopropene) were used for the isolation of cell wall polymers to find changes in their degradation pattern. Polymers were separated according to their solubility in water, CDTA, and 4 M alkali, and their monosaccharide compositions were determined. Water-soluble polymers were further characterized, and their increased yields in control and ethylene-treated fruit, in contrast to those that were treated with 1-MCP, indicated a strong association between fruit softening and changes in the cell wall water-soluble polysaccharide fraction. The results indicate that the extensive softening in the pulp of ripening papayas is a consequence of solubilization of large molecular mass galacturonans from the pectin fraction of the cell wall. This process seems to be dependent on the levels of ethylene, and it is likely that the releasing of galacturonan chains results from an endo acting polygalacturonase. (AU)

• Processo FAPESP: 02/12452-9 - Metabolismo de carboidratos durante o amadurecimento de frutos: aplicações da genômica funcional
• Beneficiário: Franco Maria Lajolo
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 07/56515-8 - Clonagem, expressão e caracterização molecular das enzimas pectinolíticas envolvidas no amolecimento da polpa durante o amadurecimento do mamão papaia
• Beneficiário: Joao Paulo Fabi
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado