Changes in cell wall pectins and their relation to postharvest mesocarp softening of 'Hass' avocados (Persea americana Mill.)
| Autor: | Orianne Gudenschwager, Reinaldo Campos-Vargas, Maria Paz Covarrubias, Troy Ejsmentewicz, Bruno G. Defilippi |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Persea food.ingredient Pectin Physiology Cold storage Cell wall disassembly Plant Science 01 natural sciences 03 medical and health sciences food Cell Wall Genetics Pectinase Softening Plant Proteins biology Chemistry food and beverages Ripening biology.organism_classification beta-Galactosidase Horticulture 030104 developmental biology Polygalacturonase Fruit Pectins Climacteric 010606 plant biology & botany |
| Zdroj: | Plant physiology and biochemistry : PPB. 128 |
| ISSN: | 1873-2690 |
| Popis: | The avocado is a climacteric fruit and begins a softening process after harvest. During ripening, the mesocarp changes in texture, and this affects fruit quality and cold storage capacity. Softening is commonly associated with cell wall disassembly in climacteric fruits. However, changes in the cell wall structure and composition during avocado softening are poorly understood. To understand this process, cell wall pectins in “Hass” avocado fruit were studied during ripening at 20 °C after harvest and after cold storage. Additionally, avocados were treated with 1-MCP to evaluate the delay in softening. Biochemical analysis showed a decrease in galacturonic acid (GalA) in alcohol-insoluble residues (AIR) and water-soluble pectin concomitant to softening, paralleled by an increase in polygalacturonase (PG) activity. In the same way, the β-galactosidase activity increased in soft avocado fruit, along with a reduction in galactose in cell wall material and the Na2CO3-soluble fraction. The arabinose content in the cell wall material did not change during softening. However, there was a change in arabinose ratios between the different fractions of pectin, mainly in the fractions soluble in water and in Na2CO3. The cold storage of avocado fruit did not induce softening of the fruit, but the content of GalA showed a substantial decrease, accompanied by an increase in PG activity. Thus, our work supports the hypothesis that the solubilization of neutral sugars such as arabinose and rhamnose, as well as the loss of galactose content mediated by the enzyme β-galactosidase, were the main factors that began the coordinated action of cell wall remodeling enzymes that resulted in the loss of firmness of avocado fruit. |
| Databáze: | OpenAIRE |
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