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vol. 11, nr. 1 (2008)
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Evaluation of the usability of sorption isotherms for specification of weight growth factor in noodle products
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Aneta Ocieczek
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Department of Hotel and Tourism Management, Maritime Academy, ul. Morska 83, 81-225 Gdynia |
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vol. 11 (2008), nr. 1,
pp. 147-157
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abstract:
The studied noodles were characterized by a homogenous chemical composition. The sorption isotherms were specified with the static-desiccator method at a temperature of 20C. The equilibrium water content essentially depended on the type of product. Significant growth of the water content was noted in both studied noodles at aw of about 0.75. Above aw = 0.75 some capillary condensation probably occurred. Based of the BET equation, the monolayer capacity was determined for the two types of noodles (noodle I – 6.34 and noodle II – 5.78 g (100 g d.m.)-1) and – on its basis - their proper sorption area (MI – 222.9 and MII – 202.9 m2 g-1). The general capillary capacity was also determined in the range of capillary condensation, showing a higher value of this parameter in the MI noodle. Based on the Kelvin equation, the most probable capillary radius was determined, and the radius of capillaries undergoing fulfilment in the initial stage of condensation. However, sorption isotherms proved to be inadequate for the prediction of weight growth in noodle products.
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keywords:
sorption isotherms, monolayer, sorption surface, water activity
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original in:
English
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