International Journal of Aquaculture, 2018, Vol.8, No.15, 112-120
119
FAO (2001) has recommended and classified samples with TVB-N value less than 25 mg-N/10 g has ‘perfect
quality’, samples with 30 mg-N/100 g has ‘good quality’, samples with up to 35 mg-N/100 g has ‘marketable
quality’, and samples with TVB-N of more than 35 mg-N/100g has ‘spoiled’ (Çelik et al., 2012). It is however
difficult to fix the limit of TVB-N for cured and processed products due to variety and diversity of products and
their processing procedure. The limiting level for rejection of TVB-N is 30-40 mg-N/100g for storage at ambient
temperature (Connell, 1995). In freshly caught fish TVB-N content is generally less than 10 mg-N/100g and does
not exceed 15 mg-N/100g except for pelagic fish (Pérez et al., 2008; Nollet and Toldra, 2009). Values obtained in
this study falls within this range. Based on results obtained in this study, all the samples were of perfect quality
during the first week. Thereafter, their quality deteriorated in varying proportions during the storage period.
During the sixth week of storage, most unsalted smoked fishes had values exceeding 30 mg-N/100g, hence they
were close to being rejected.
4 Conclusion
Smoking and drying of the fishes resulted in changes in the proximate composition of the fishes. Protein, fat, ash
and carbohydrate were all observed to increase after processing in all the fish types. Moisture content reduced
after processing, however, it increased during storage. There was increase in the total volatile base nitrogen during
the storage period which was a sign of deterioration. Storage of the processed fishes at room temperature reduced
the heavy metals concentration as concentrations were considerably reduced.
Authors’ contributions
The third author conceived and designed the study. The first author carried out the experiment under the supervision of second and
third authors. The second and third authors analysed the laboratory data. The second author produced the first and final draft,
presented the draft for publication. All authors read and approved the final manuscript.
Acknowledgements
The authors acknowledge the contributions of the Department of Food Science and Technology, Obafemi Awolowo University,
Ile-Ife for the provision of the laboratory facilities for the study.
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