Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C
Moisture sorption isotherms (MSI’s) of skimmed milk powder in the temperature range of 5–20 °C were determined using manometric method. MSI’s, which show the water content versus water activity (Aw) at a constant temperature, are used to describe relationships between water content and equilibrium s...
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| Format: | Article |
| Language: | English |
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Mendel University Press
2012-01-01
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| Series: | Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis |
| Subjects: | |
| Online Access: | https://acta.mendelu.cz/60/6/0225/ |
| _version_ | 1818190550948380672 |
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| author | Jitka Langová Jiří Štencl Václav Vlášek |
| author_facet | Jitka Langová Jiří Štencl Václav Vlášek |
| author_sort | Jitka Langová |
| collection | DOAJ |
| description | Moisture sorption isotherms (MSI’s) of skimmed milk powder in the temperature range of 5–20 °C were determined using manometric method. MSI’s, which show the water content versus water activity (Aw) at a constant temperature, are used to describe relationships between water content and equilibrium state relative vapour pressure (RVP). The equilibrium moisture content (EMC) of skimmed milk powder samples is growing with an increase of Aw at a constant temperature both for water adsorption and desorption. Isotherms were found to be type II of Brunauer-Emmett-Teller classification. It is the type most common for foods. The shape of created isotherms was sigmoid. Structural modifications of crystals were observed during adsorption in the microscope, too. Critical value of EMC of tested samples corresponding to the Aw equal to 0.6 for adsorption was 6.50% MC (w.b.) at temperature 5 °C, 9.15% MC (w.b.) at temperature 10 °C, and 7.71% MC (w.b.) at temperature 20 °C. These values determine optimal conditions for storage from the point of view microorganisms grow, Aw<0.6. |
| first_indexed | 2024-12-12T00:00:30Z |
| format | Article |
| id | doaj.art-66c4959bab4240d1b6b57b818f17c0a6 |
| institution | Directory Open Access Journal |
| issn | 1211-8516 2464-8310 |
| language | English |
| last_indexed | 2024-12-12T00:00:30Z |
| publishDate | 2012-01-01 |
| publisher | Mendel University Press |
| record_format | Article |
| series | Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis |
| spelling | doaj.art-66c4959bab4240d1b6b57b818f17c0a62022-12-22T00:45:14ZengMendel University PressActa Universitatis Agriculturae et Silviculturae Mendelianae Brunensis1211-85162464-83102012-01-0160622523010.11118/actaun201260060225Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °CJitka Langová0Jiří Štencl1Václav Vlášek2Ústav hygieny a technologie mléka, Veterinární a farmaceutická univerzita Brno, Palackého 1/3, 612 42 Brno, Česká republikaÚstav zemědělské, potravinářské a environmentální techniky, Mendelova univerzita v Brně, Zemědělská 1, 613 00 Brno, Česká republikaÚstav hygieny a technologie mléka, Veterinární a farmaceutická univerzita Brno, Palackého 1/3, 612 42 Brno, Česká republikaMoisture sorption isotherms (MSI’s) of skimmed milk powder in the temperature range of 5–20 °C were determined using manometric method. MSI’s, which show the water content versus water activity (Aw) at a constant temperature, are used to describe relationships between water content and equilibrium state relative vapour pressure (RVP). The equilibrium moisture content (EMC) of skimmed milk powder samples is growing with an increase of Aw at a constant temperature both for water adsorption and desorption. Isotherms were found to be type II of Brunauer-Emmett-Teller classification. It is the type most common for foods. The shape of created isotherms was sigmoid. Structural modifications of crystals were observed during adsorption in the microscope, too. Critical value of EMC of tested samples corresponding to the Aw equal to 0.6 for adsorption was 6.50% MC (w.b.) at temperature 5 °C, 9.15% MC (w.b.) at temperature 10 °C, and 7.71% MC (w.b.) at temperature 20 °C. These values determine optimal conditions for storage from the point of view microorganisms grow, Aw<0.6.https://acta.mendelu.cz/60/6/0225/skimmed milk powderwater activitysorption curve |
| spellingShingle | Jitka Langová Jiří Štencl Václav Vlášek Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis skimmed milk powder water activity sorption curve |
| title | Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C |
| title_full | Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C |
| title_fullStr | Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C |
| title_full_unstemmed | Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C |
| title_short | Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C |
| title_sort | water sorption isotherms of skimmed milk powder within the temperature range of 5 20 °c |
| topic | skimmed milk powder water activity sorption curve |
| url | https://acta.mendelu.cz/60/6/0225/ |
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