Shelf-life of smoked eel fillets treated with chitosan or thyme oil

Abstract

The present study examined the effect of natural antimicrobials: Chitosan, thyme oil and their combination, on the shelf-life of smoked eel fillets stored under vacuum packaging (VP) at 4°C. Based on sensory odor data smoked eel fillets had a shelf-life of 35 (control), 42 (thyme treated and>49 (thyme, chitosan-thyme treated) days. The thiobarbituric acid value (TBA) value of the control eel sample was significantly higher than the chitosan-thyme-treated eel samples. The use of chitosan singly, or in combination with thyme oil reduced lipid oxidation (TBA) of the smoked eel samples. A trimethylamine nitrogen (TMA-N) value of 10mgN/100g, could be suggested as an indication of smoked eel spoilage initiation. Control and treated eel reached total volatile basic nitrogen (TVB-N) values of 13.1-31.5mgN/100g below the maximum permissible level of TVB-N in fish and fishery products. Eel samples reached the value of 7.0logcfu/g (Total Plate Count, TPC) on days 35 (smoked) and 42 (thyme treated), whereas both chitosan and chitosan-thyme treated eel samples never reached this limit value. Results of our study show thyme or chitosan (singly, or in combination) inhibit the growth of mesophilic bacteria and extend the shelf-life of smoked eel.

Evaluation of weakly acidic electrolyzed water and modified atmosphere packaging on the shelf life and quality of farmed puffer fish (Takifugu obscurus) during cold storage

“…The results obviously showed that WAEW treatment could maintain lower TMA values for puffer fish during cold storage. A TMA value of 10.00 mg/100 has been considered for the upper acceptability limit of some fish freshness (El‐Obeid et al, ). Based on our TMA data (in all treated samples on the 18th day), 5.00 mg/100 g could be considered as the upper acceptability limit for puffer fish, which amounted to the microbiological TVC limit value on the 18th day (Figure 1a).…”

Prospect of Polysaccharide-Based Materials as Advanced Food Packaging

“…Inclusion of rosemary oil in chitosan/montmorillonite matrix showed to retard chicken poultry lipid oxidization, discoloration and microbial spoilage [203]. On the other hand, chitosan incorporated with thyme oil [204], cinnamon oil [205] and clove oil [206] proved to prolong the shelf life of various sorts of fishes.…”

Gökkuşağı Alabalığı (Oncorhynchus mykiss) Filetolarının Raf Ömrünü Uzatmak İçin Defne Esansiyel Yağı ve Vakum Paketlemenin Birlikte Kullanımı

“…In line with the aforementioned study, it was observed that the EO enabled a reduction in the initial Pseudomonas count. In their study which examined the effect of chitosan, thyme oil or their combinations on the shelf-life of smoked eel fillets stored under vacuum packaging (VP) at 4°C, El-Obeid et al [8] reported that in the treated samples, the Pseudomonas count had been lower throughout the period of storage. This study also produced similar findings.…”

“…TVB-N is produced by the degradation of proteins and nonprotein nitrogenous compounds as a result of microbial activity and used as a fish spoilage indicator [9,29,30] . The maximum permissible level of TVB-N in fish and fishing products is 35 mg N/100 g [8,31,32] . The initial (day 0) TVB-N value was 16.6 mg/100 g in the control group and it was determined that this value increased in all groups throughout the storage.…”

“…There has been a growing demand for natural products as an alternative to synthetic food additives [6] . Preservation methods employing natural products have become a focus of interest for researches, thus many studies have been conducted especially to extend the shelf-life of fish and other seafood [6][7][8][9][10][11] .…”