the species and variety. The degree of ripeness of fruit
has a significant influence on the content of sugars, minerals
and acids. The sugar content in fully ripe apples is high
due to complete hydrolysis of starch. Then, during storage,
sugars content begins to decrease, as they are consumed in
respiration process.
During ripening on the tree, the organic acid content in
apples increases, reaches a maximum for a few days before
harvest and then slightly decreases. However, acid content
during storage has been gradually declining. It is thought
that part of them, in addition to sugars, may be consumed
in the process of respiration. Storage leads to softening of
fruits, which is mediated by loss of cell-to-cell adhesion.
Tissue from soft fruits has rounded cells, bigger cell separation
and larger intercellular spaces. Analyses of
pectin fractions have shown that apple softening is usually
associated with the increased content of water-soluble
pectin and reduced galactose and arabinose residues. A
number of cell-wall-modifying enzymes that have been
found in ripening apples may cause softening. The enzyme
originally considered responsible for pectin solubilization,
and therefore, softening was polygalacturonase (PG), with
activities of both exo-PG and endo-PG detected in ripening
apples. Direct measurements of turgor showed that
the species and variety. The degree of ripeness of fruithas a significant influence on the content of sugars, mineralsand acids. The sugar content in fully ripe apples is highdue to complete hydrolysis of starch. Then, during storage,sugars content begins to decrease, as they are consumed inrespiration process.During ripening on the tree, the organic acid content inapples increases, reaches a maximum for a few days beforeharvest and then slightly decreases. However, acid contentduring storage has been gradually declining. It is thoughtthat part of them, in addition to sugars, may be consumedin the process of respiration. Storage leads to softening offruits, which is mediated by loss of cell-to-cell adhesion.Tissue from soft fruits has rounded cells, bigger cell separationand larger intercellular spaces. Analyses ofpectin fractions have shown that apple softening is usuallyassociated with the increased content of water-solublepectin and reduced galactose and arabinose residues. Anumber of cell-wall-modifying enzymes that have beenfound in ripening apples may cause softening. The enzymeoriginally considered responsible for pectin solubilization,and therefore, softening was polygalacturonase (PG), withactivities of both exo-PG and endo-PG detected in ripeningapples. Direct measurements of turgor showed that
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