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| Author(s): |
Ana Claudia Chesca
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 1995-11-30 |
| Advisor: | Luiz Gonzaga do Prado Filho |
| Abstract | |
In the actual work the performance evaluation of an experimental equipment for practical determination of moisture equilibrium curves or adsorcion isotherms were carried out. The built equipment is inexpensive, of easy construction and operation, so that it does not need specialized tools or manocuvre. Salt satured solutions were used to adjust the water activity (Aw) inside the equipment, compressing the highest scope of values in practical storage and conservation of particulated material, which are 0,51; 0,57; 0,67; 0,75; 0,79; 0,84 and 0,91. In order to determine the adsorption isotherms, "Deusa" manihot flour, "Kitano" corn meal, whole and coreless soybean floury from Céu Azul and IAC- 08 cultivars. Recycled and non-recycled samples of these flours were used. The adsorption isotherms of these materials were taken at 30°C, 35°C and 40°C. The total exposition time of the samples to a given Aw was 34 hours with intermediary weightings at the 10th, 11th, 12th, 24th, 25th, 26th, 27th, 28th, 29th, 30th, 31st, 32nd, 33rd and 34rd hours. After the last data taking, which was at the 34th hour, the samples were submitted to microbiological analysis, in order to determine the presence of search degradating microrganisms. It has been observed that necessary time to settle the equilibrium between the tested flours and the studied water activities (Aw) were sensibly shorter, ranging from 10 to 12 hours, when compared to static equilibrium methods. (AU) | |