Publication Date:
2021-07-16
Description:
In this study, quality of fresh, slow frozen and quick frozen tilapia (gutted and) fillets and its changes during storage at -18°C were investigated. For preparation the samples, fresh tilapia fillets were frozen by slow and quick frozen methods. Slow frozen samples were prepared by storing the packed fillets directly in the -18°C. The sprila freezing tunle with -30C° was also used for preparation the quick frozen sample. The quick frozen samples were then stored at -18C for six months. Proximate composition, fatty acid profiles, TBA, PV, TVN, Total cuont, Drip loss, and sensory evaluation of the samples were determined in every month. Scanning Electron Microscopy (SEM) was used for study on the effects of the frozen condition on the microstructure of the fillets. Results indicated that two different frozen methods had significantly different effects on the quality of the samples. Most of the proximate composition (protein, moistre and fat) reduced during the storage. Quick frozen samples had significantly (P〈0.05) lower reduction than slow frozen samples. All of the chemical quality indexes (PV, TBA, and TVN) increased during the storage as compered to the fresh samples. In these paramethers, the slow freezing had higher changes than quick freezing metods (P〈0.05). The microbial properties of the samples showed decrese during the storage. Lower amont of total cuont was observed at the end of the storage time in the quick frozen samples than slow frozen once (P〈0.05). The large changes in the fatty acid profiles of the sample were fond in all samples. During the storage SFA and MUF of the samples increased however, the PUFA decresed. A lower change was obseved in the quick frozen samples than slow frozen samples (P〈0.05). Drip loss was increased in both frozen samples during the storage period. The percentage of the drip in the slow frozen samples was significantly higer than quick frozen samples (P〈0.05). SEM micrographs were also showed that the chnges in the microstructur of the samples was different in the slow and frozen samples. Slow freezing methods had higher damge in the microstructure of the sample then quick freezing mathods. Sensory evaluation of the samples indicated that a better acceptability in the quick frozen samples than slow frozen sample (P〈0.05).
Keywords:
Aquaculture
;
Iran
;
Nile tilapia
;
Red Tilapia
;
Quick freezing
;
Slow freezing
;
Fatty acids
;
Scanning Electron Microscope
;
SEM
;
Nutritional value of fish
;
Investigation
Repository Name:
AquaDocs
Type:
monograph
Format:
application/pdf
Format:
application/pdf
Format:
151
Permalink
