Relationship between fruit softening and cell wall polysaccharides in pears after different storage periods

Abstract

Abstract We investigated the relationship between flesh firmness and the cell wall polysaccharides of ‘Marguerite Marillat’ and ‘La France’ pears that had retained or lost their ripening capacity. In both cultivars, fruit softened and reached a buttery and juicy texture after short-term storage (1 month at 1 °C), while fruit softened but never reached that texture after long-term storage (4 months for ‘Marguerite Marillat’ or 5 months for ‘La France’ at 1 °C). In ‘Marguerite Marillat’ pears, the water-soluble polyuronide (WSP) levels in fruit after long-term storage tended to be lower than those after short-term storage, when compared with fruit having similar flesh firmness. In ‘La France’ pears, lower flesh firmness correlated with higher WSP content in fruit after short-term storage, while the lower the flesh firmness, the lower the WSP content in fruit after long-term storage. The relationship between flesh firmness and alkali-soluble polyuronide (ASP) content showed the highest correlations in both cultivars among cell wall polysaccharides determined in this study. Lower flesh firmness correlated with lower ASP content, independent of cultivar and storage period. Fruit, after short-term storage, contained more ASP than after long-term storage in both cultivars, when compared with fruit having similar flesh firmness. The differences in the amount of hemicellulosic polysaccharides between hard and soft fruit were slight. There was no negative correlation between flesh firmness and cellulose content, independent of cultivar and storage period. These data suggest that lower polyuronide content, especially WSP and ASP, in fruit after prolonged storage is one cause of the inferior texture of pears after prolonged storage.