Dezhand, M. R. (2012) Microbial, physico-chemical and sensory quality changes of Oncorhynchus mykiss fillet processed by the sous-vide giikooc during refrigerated storage. Masters thesis, University of Zabol.
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Abstract
Nowadays, using appropriate packaging techniques to improve quality, increase shelf life and prevent economic losses are taken into account. The aim of this work was to determine microbiological, Physicochemical and sensory changes of rainbow trout (Oncorynchus mykiss) fillets processed by sous vide cooking method during chilled storage at 4±8ºC. For this purpose, a total of 90 rainbow trout (250-300 g) purchased. The fish were cleaned, filleted and divided into 100g batches and sterile packages and then underwent a vacuum packed sous vide process using a vacuum sealing machine. In order to prepare cooking treatments, first group of vacuum-packed fillets were cooked in a bath of water: after reaching a core temperature of 65 °C, cooking was prolonged for 15 min (LTLT treatment or low and prolonged cooking) and the second group were cooked in the same way at a core of 85 °C for 5 min (HTST treatment or high and fast cooking). Controlled treatment was maintained in refrigerator (1±4ºC) for 21 days. Chemical analysis (pH, moisture, total lipid, total protein and ash), factors of fat Corruption measurement (PV, TBA and FFA), the changes of free fatty acids (FFA), microbial (TVC, PTC, EBC and LAB) were determined. Also, sensory evaluations (texture, color, taste and smell) were assessed in the days of 0, 3, 7, 14 and 21. The results showed that the quantity of chemical indices (pH, PV, TBA AND FFA) increased during the storage period but at the end of the storage period, these amounts for 85 °C treatment were 5 minutes less than the other treatments. Based on chemical indices of quality control obtained during the length of the 14-day storage period. At fatty acids experiments, the omega-3 family that are necessary to maintain healthy, was significantly (P<0.05) higher at 85 °C treatment in comparison with controlled. Results of microbial indices (TVC, PTC, EBC and LAB) showed that fillets at 85 °C treatment survive longer because these fillets did not reach MRL after 21 days. Results of sensory evaluations showed positive effect on cooked treatment in comparison with controlled. Generally, results of chemical, microbial and sensory analysis showed that sous vide process causes increasing in survival time of rainbow trout fillets maintained in a refrigerator (1±4ºC) up to 14 days of chemically and 21 days of microbial and sensory treatments.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Sous-vide cooking, rainbow trout, maintenance in refrigerator |
| Subjects: | S Agriculture > SH Aquaculture. Fisheries. Angling |
| Depositing User: | admin admin1 admin2 |
| Date Deposited: | 24 Oct 2016 06:51 |
| Last Modified: | 24 Oct 2016 06:51 |
| URI: | http://eprints.uoz.ac.ir/id/eprint/875 |
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