Developmental and Ripening-Related Effects on the Cell Wall of Pepino (Solanum muricatum) Fruit

Abstract

Several cell wall components in ripening pepino fruit have been quantitatively and qualitatively characterised, with the aim of identifying their contributions to the loss of tissue firmness. Pepinos were graded into nine groups based on progressive, characteristic skin colour changes, previously shown to correspond with decreasing fruit firmness. While fruit softening began when the pepinos were still green but with newly acquired purple stripes, the first significant quantitative signs of cell wall modification (total pectin and hemicellulose content declining and CDTA‐soluble pectin content increasing, on a fresh weight basis) were detectable later in ripening, when the fruit began to acquire yellow skin pigmentation. Gel fractionation studies demonstrated that there were increased levels of low‐molecular‐weight pectin and xyloglucan during pepino ripening. The change in molecular weight distribution of CDTA‐soluble pectin occurred as fruit started to acquire yellow pigmentation, while xyloglucan polymers were modified at an earlier stage that coincided with the initial loss of firmness. © 1997 SCI.

Postharvest quality of pepino ( Solanum muricatum Ait.) fruit in controlled atmosphere storage

“…Vertical bars represent n ± SE. de Vré, & Heyes, 1997). At the time of harvest mature pepino fruits had a higher content of insoluble pectic substances in comparison to fruits at an advanced ripening stage (Fig.…”

“…4). This suggested that ripe pepino fruits may contain a higher activity of pectolytic enzymes contributing to the degradation of the cell wall (OÕDonoghue et al, 1997). Ripe fruits stored under air atmosphere conditions revealed a sharp increase of water-soluble pectin, whereas changes were significantly inhibited by the CA conditions during storage.…”

Tomato quality in controlled atmosphere storage, modified atmosphere packaging and cold storage

“…Cenci et al (1997) also reported that CAS treatment enhances the retention of textural properties by preventing the synthesis of cell wall degrading enzymes. Softening is due to the breakdown of cell wall structure's carbohydrates and the increase in soluble pectin substances that results in weakening of the cell walls and reduction of the cohesive forces binding cells together (Heyes et al 1994;O'Donoghue et al 1997). Heyes et al (1994) also suggested that higher CO 2 concentration results in suppression of the degradation of protopectin to soluble pectin thus reducing fruit softening.…”

Fermentation characteristics of polysaccharide fractions extracted from the cell walls of soya bean cotyledons

“…Spagnuolo et al 31 speculated that, for the degradation of sugar beet pulp using purified enzymes, pectin forms a barrier to the degradation of the other polysaccharides. Research on fruits32–36 shows a relationship between cell wall pectin content and pectin structure, and cell wall firmness and swelling capacity. These effects may well be mediated through pore size.…”