Sorbitol Metabolism, the Climacteric, and Watercore in Apples

Abstract

Extraction and assay of sorbitol dehydrogenase (SDH) throughout fruit maturation of 3 apple (Malus domestica Borkh.) cultivars, watercore-resistant ‘Golden Delicious,’ occasionally susceptible ‘McIntosh’, and normally susceptible ‘Starkrimson,’ showed no relationship between susceptibility to watercore and extractable enzyme activity. There was, however, a relationship between increased SDH activity and onset of the climacteric as measured by ethylene and CO2 evolution, suggesting that SDH, like certain other enzymes, increases during maturation.

Application of NMR techniques for the evaluation of fruit internal quality and physical properties of food

“…Watercore is a physiological disorder affecting apples and pears (Inomata and Suzuki, 2001;Kajiura et al, 1976;Yamaki et al, 1976;Yamaki et al, 1977), involving the appearance of fluid-filled intercellular spaces with elevated sorbitol rates (Marlow and Loescher, 1985). In some varieties and in some parts of the world, such as Japan, it is considered as an indicator of full ripeness and they are called 'honeyed apples' (Kasai and Arakawa, 2010).…”

“…Though this disorder was described a long time ago (Evans, 1909;Faust M, 1969), its physiological mechanism is only partially understood. Several authors have described physiological and biochemical factors affecting watercore: for example, Marlow and Loescher, (1985) found that the enzyme sorbitol dehydrogenase activity increased during maturation but no relationship was found between the susceptibility of watercore development and the activity of this enzyme. Wang and Faust, (1992a) determined that apples affected by watercore produce more ethylene and had higher contents of polyamine compounds.…”

“…Watercore is a physiological disorder affecting apples when the fruit is still attached to the tree (Marlow andLoescher, 1984, Yamada et al, 2012). Normally, watercore starts around the vascular bundles (Faust et al, 1969, Harker and Watkins, 1999, Kasai and Arakawa, 2010 and, except for some particular cultivars, symptoms are invisible from the exterior of the fruit (Faust et al, 1969).…”