Osmotic dehydration of apple tissue (Malus pumila, Granny Smith cultivar) to water activity (aw) 0.97 or
0.94 with maltose or maltose syrup solutions was studied and compared with previous results using glucose
or trehalose as humectants. Structure (optical and transmission electronic microscopy observations),
rheological properties (small scale dynamic oscillatory and creep/recovery measurements and large scale
compression force-deformation testing), and water mobility (1
H NMR spectra) of parenchymatous apple
tissue were significantly affected by osmotic treatments. Osmotically dehydrated apples became soft and
extensible and lost crispness and hardness, while the behavior of the moduli G0 and G00 indicated weaker
gels after osmosis. Compression properties of the tissues abruptly changed after osmotic dehydration to
aw 0.97, while reduction to aw 0.94 led to a compression response more similar to that of untreated
apples. Compression behavior and state and distribution of water in apple tissues were influenced by
the osmotic agent employed and the aw level, while in general mechanical spectra and creep analysis
were not able for distinguishing physical differences between osmotic treatments assayed
Osmotic dehydration of apple tissue (Malus pumila, Granny Smith cultivar) to water activity (aw) 0.97 or0.94 with maltose or maltose syrup solutions was studied and compared with previous results using glucoseor trehalose as humectants. Structure (optical and transmission electronic microscopy observations),rheological properties (small scale dynamic oscillatory and creep/recovery measurements and large scalecompression force-deformation testing), and water mobility (1H NMR spectra) of parenchymatous appletissue were significantly affected by osmotic treatments. Osmotically dehydrated apples became soft andextensible and lost crispness and hardness, while the behavior of the moduli G0 and G00 indicated weakergels after osmosis. Compression properties of the tissues abruptly changed after osmotic dehydration toaw 0.97, while reduction to aw 0.94 led to a compression response more similar to that of untreatedapples. Compression behavior and state and distribution of water in apple tissues were influenced bythe osmotic agent employed and the aw level, while in general mechanical spectra and creep analysiswere not able for distinguishing physical differences between osmotic treatments assayed
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