Carbohydrate composition and content of organic acids in fresh and stored apples

The contents of low-molecular-weight carbohydrates (LMWC; sorbitol, glucose, fructose and sucrose), starch, dietary fibre and organic acids were determined in seven apple cultivars at the start and end of the consumption interval. The cultivars included were Summered, Aroma, Ingrid Marie, Cox Orange, Mutzu, Belle de Boskoop and Jonagold. The total content of LMWG ranged between 615 and 716 g kg^-1 dry matter (DM). The dominating sugar was fructose, corresponding to on average 57% (range 48-62%) of the total LMWG. However, in Cox Orange the sucrose content was considerably higher and the fructose and sucrose contents constituted approximately 46% each. Total dietary fibre content was similar in the cultivars (total dietary fibre 1604 ± 20 g kg^-1 DM), except for Belle de Boskoop which had a higher content (203 g kg^-1 DM). Mutzu had a lower proportion of soluble fibre (27% of total dietary fibre) compared with the others (mean 32%). The organic acid content was on average 80 ± 4 g kg^-1 DM, except for two of the cultivars (Summered and Belle de Boskoop) which had a higher content (105 ± 6 g kg^-1 DM). Interestingly, the organic acid content was only slightly reduced upon storage in the case of Belle de Boskoop, whereas there was a substantial decrease in all the other cultivars (p < 0.001). Sucrose (p < 0.01) and starch (p < 0.05) contents decreased in all cultivars following storage, whereas sorbitol (p < 0.05) and total dietary fibre (p < 0.05) contents increased. It is concluded that the observed differences in composition are of such magnitude that they may affect both nutritional and sensory properties. (C) 2000 Society of Chemical Industry.