Moisture sorption isotherm and thermal characteristics of freeze-dried tuna
Water activity is considered an important factor in assessing the stability of food. Understanding the relationship between water activity and equilibrium moisture content (moisture sorption isotherm) benefits food processing in terms of modeling of drying and estimation of shelf life. In addition,...
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ISEKI_Food Association (IFA)
2019-04-01
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| Series: | International Journal of Food Studies |
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| Online Access: | https://www.iseki-food-ejournal.com/article/391 |
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| author | Mohammad Shafiur Rahman Mohammed Khalfan Al-Khusaibi Kutaila Abbas AL-Farsi Ismail Mohamed Al-Bulushi Aisha Abushelaibi Nasser Al-Habsi |
| author_facet | Mohammad Shafiur Rahman Mohammed Khalfan Al-Khusaibi Kutaila Abbas AL-Farsi Ismail Mohamed Al-Bulushi Aisha Abushelaibi Nasser Al-Habsi |
| author_sort | Mohammad Shafiur Rahman |
| collection | DOAJ |
| description | Water activity is considered an important factor in assessing the stability of food. Understanding the relationship between water activity and equilibrium moisture content (moisture sorption isotherm) benefits food processing in terms of modeling of drying and estimation of shelf life. In addition, glass transition helps to quantify molecular mobility which helps in determining the stability of food. The aim of this study was to determine the moisture sorption isotherm and thermal characteristics of freezedried tuna. These characteristics will help in determining the monolayer moisture and glassy state of the product, at which food is considered most stable. Moisture sorption isotherm at 20 oC and thermal characteristics (over a wide temperature range i.e. from -90 to 250 oC) of freeze-dried tuna flesh were measured. Isotherm data were modeled by BET (Brunauer-Emmett-Teller) and GAB (GuggenheimAnderson–De Boer) models. The GAB and BET monolayer water values were determined as 0.052 and 0.089 g g−1 dry-solids (dry-basis), respectively. In the case of samples at moisture contents above 0.10 g g−1 (wet basis), DSC (Differential Scanning Calorimetry) thermograms showed two-step state changes (i.e. two glass transitions), one exothermic peak (i.e. molecular ordering) and another endothermic peak (i.e. solids-melting). However, the sample at moisture content of 0.046 g g−1 showed three-step state changes (i.e. three glass transitions). The multiple glass transition could be explained by the natural heterogeneity of tuna flesh and inhomogeneity due to molecular incompatibility of the different compositions. The moisture content did not affect the first glass transition temperature nor the exothermic peak (p>0.05), whereas the third glass transition temperature decreased (i.e. plasticized) with increasing moisture content (p<0.05). The solids-melting peak temperature decreased, and enthalpy increased with decreasing moisture content (p<0.05). |
| format | Article |
| id | doaj-art-4d543a5f9275470b940512f23fa6bc78 |
| institution | Kabale University |
| issn | 2182-1054 |
| language | English |
| publishDate | 2019-04-01 |
| publisher | ISEKI_Food Association (IFA) |
| record_format | Article |
| series | International Journal of Food Studies |
| spelling | doaj-art-4d543a5f9275470b940512f23fa6bc782024-12-09T23:15:54ZengISEKI_Food Association (IFA)International Journal of Food Studies2182-10542019-04-018110.7455/ijfs/8.1.2019.a8Moisture sorption isotherm and thermal characteristics of freeze-dried tunaMohammad Shafiur Rahman0Mohammed Khalfan Al-Khusaibi1Kutaila Abbas AL-Farsi2Ismail Mohamed Al-Bulushi3Aisha Abushelaibi4Nasser Al-Habsi5Department of Food Science and Nutrition, Sultan Qaboos University, Muscat, OmanDepartment of Food Science and Nutrition, Sultan Qaboos University, Muscat, OmanDepartment of Food Science and Nutrition, Sultan Qaboos University, Muscat, OmanDepartment of Food Science and Nutrition, Sultan Qaboos University, Muscat, OmanCollege of Food and Agriculture, Food Science Department, UAE UniversityDepartment of Food Science and Nutrition, Sultan Qaboos University, Muscat, OmanWater activity is considered an important factor in assessing the stability of food. Understanding the relationship between water activity and equilibrium moisture content (moisture sorption isotherm) benefits food processing in terms of modeling of drying and estimation of shelf life. In addition, glass transition helps to quantify molecular mobility which helps in determining the stability of food. The aim of this study was to determine the moisture sorption isotherm and thermal characteristics of freezedried tuna. These characteristics will help in determining the monolayer moisture and glassy state of the product, at which food is considered most stable. Moisture sorption isotherm at 20 oC and thermal characteristics (over a wide temperature range i.e. from -90 to 250 oC) of freeze-dried tuna flesh were measured. Isotherm data were modeled by BET (Brunauer-Emmett-Teller) and GAB (GuggenheimAnderson–De Boer) models. The GAB and BET monolayer water values were determined as 0.052 and 0.089 g g−1 dry-solids (dry-basis), respectively. In the case of samples at moisture contents above 0.10 g g−1 (wet basis), DSC (Differential Scanning Calorimetry) thermograms showed two-step state changes (i.e. two glass transitions), one exothermic peak (i.e. molecular ordering) and another endothermic peak (i.e. solids-melting). However, the sample at moisture content of 0.046 g g−1 showed three-step state changes (i.e. three glass transitions). The multiple glass transition could be explained by the natural heterogeneity of tuna flesh and inhomogeneity due to molecular incompatibility of the different compositions. The moisture content did not affect the first glass transition temperature nor the exothermic peak (p>0.05), whereas the third glass transition temperature decreased (i.e. plasticized) with increasing moisture content (p<0.05). The solids-melting peak temperature decreased, and enthalpy increased with decreasing moisture content (p<0.05).https://www.iseki-food-ejournal.com/article/391Dried fishSorption isothermTunaThermal transitionSolids-melting |
| spellingShingle | Mohammad Shafiur Rahman Mohammed Khalfan Al-Khusaibi Kutaila Abbas AL-Farsi Ismail Mohamed Al-Bulushi Aisha Abushelaibi Nasser Al-Habsi Moisture sorption isotherm and thermal characteristics of freeze-dried tuna International Journal of Food Studies Dried fish Sorption isotherm Tuna Thermal transition Solids-melting |
| title | Moisture sorption isotherm and thermal characteristics of freeze-dried tuna |
| title_full | Moisture sorption isotherm and thermal characteristics of freeze-dried tuna |
| title_fullStr | Moisture sorption isotherm and thermal characteristics of freeze-dried tuna |
| title_full_unstemmed | Moisture sorption isotherm and thermal characteristics of freeze-dried tuna |
| title_short | Moisture sorption isotherm and thermal characteristics of freeze-dried tuna |
| title_sort | moisture sorption isotherm and thermal characteristics of freeze dried tuna |
| topic | Dried fish Sorption isotherm Tuna Thermal transition Solids-melting |
| url | https://www.iseki-food-ejournal.com/article/391 |
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