EFFECT OF MODIFIED ATMOSPHERE PACKAGING ON THE QUALITY OF SMOKED CATFISH

Mild processing of seafood-A review

Recent years have shown a tremendous increase in consumer demands for healthy, natural, high-quality convenience foods, especially within the fish and seafood sector. Traditional processing technologies such as drying or extensive heating can cause deterioration of nutrients and sensory quality uncompilable with these demands. This has led to development of many novel processing technologies, which include several mild technologies. The present review highlights the potential of mild thermal, and nonthermal physical, and chemical technologies, either used alone or in combination, to obtain safe seafood products with good shelf life and preference among consumers. Moreover, applications and limitations are discussed to provide a clear view of the potential for future development and applications. Some of the reviewed technologies, or combinations thereof, have shown great potential for non-seafood products, yet data are missing for fish and seafood in general. The present paper visualizes these knowledge gaps and the potential for new technology developments in the seafood sector. Among identified gaps, the combination of mild heating (e.g., sous vide or microwave) with more novel technologies such as pulsed electric field, pulsed light, soluble gas stabilization, cold plasma, or Ohmic heat must be highlighted. However, before industrial applications are available, more research is needed.

Effects of smoking processes on the nutritional value and fatty acid composition of Zander fish (

This study aimed to estimate the nutritional quality of Sander lucioperca fillets and alterations in lipid quality following hot and cold smoking processes. Our results revealed that the total fat content of zander fillets was 1.86 g/100g. Polyunsaturated fatty acids (PUFAs) were higher than saturated and monounsaturated fatty acids in fresh tissue samples. Arachidonic, docosahexaenoic and eicosapentaenoic acids were the most abundant PUFAs. Differences in the fatty acid compositions of the smoked and fresh fillet were significant, with a decrease in (PUFAs) in the proportion of total fatty acids. The fatty acid profile of the neutral lipids was unchanged after the cold smoking process, whereas PUFAs decreased significantly during both smoking processes, especially the hot smoking process. Our findings showed a partial alteration of polar lipids. Both smoking treatments produced lipoperoxidation and lipid oxidation in the fillets. Other investigational smoking conditions should be tested to reduce such oxidation and hydrolysis in fillets, which could be susceptible to off-flavors and off-odors.

Innovative technologies for producing and preserving intermediate moisture foods: A review

Intermediate moisture foods (IMF) or semi-dried foods (SDF) have gained more attention worldwide having features very similar to fresh food products, but with a longer shelf life. This review presents the recent developments in novel technologies and methods for the production and preservation of IMF. These include new drying methods, using agents to reduce water-activity, innovative osmotic dehydration technologies, electro-osmotic dewatering, thermal pasteurization, plasma treatments (PT), high pressure processing (HPP), modified atmosphere packaging (MAP), edible coating, active packaging (and energy efficiency, improve quality and extend the shelf life of the final food AP) and hurdle technologies (HT). Innovative methods applied to producing and preserving IMF can enhance both drying products. Yet more systematic research is still needed to bridge knowledge gaps, in particular on inactivation kinetics and mechanisms related to thermal and non-thermal pasteurization technologies for control of pathogens and spoilage micro-organisms in IMF.

Assessment of quality and safety of traditional smoked spotted tilapia fish (Tilapia mariae) from Lagos State, Nigeria

Purpose

– This study aims to assess the quality and microbial safety of traditional smoked spotted tilapia fish from Lagos State and, by doing so, determine the quality and microbial safety level of traditional smoked spotted tilapia fish, their distribution, effects and possible public health implications of the quality/rancidity indices and microorganisms on the consumers.

Design/methodology/approach

– Fresh spotted tilapia fish (100 samples) were collected from 20 different fishing/processing centres and divided into two batches. One batch was smoked with local drum kiln at processing centres, and the second batch was smoked with convective smoking kiln as control in the laboratory. Each batch was assessed for moisture content, protein content, fat content, crude fibre content, ash content, pH, thiobarbituric acid (TBA), total volatile base- nitrogen (TVB-N), trimethylamine (TMA), peroxide value (PV) and free fatty acid (FFA) values. Microbiological analyses were also conducted. Each batch was assessed for total viable count (TVC), fungal count, Listeria monocytogenes count, Staphylococcus aureus count, Salmonella paratyphi count and presence or absence of Escherichia coli.

Findings

– The results of the proximate composition, quality indices and microbiological analyses revealed that there was significant variations (p < 0.05) between smoked fish with different smoking methods. The mean pH, TBA, TVB-N, TMA, PV and FFA values of fresh and smoked spotted tilapia fish samples were within the range recommended by United States Food and Drug Administration. The mean TVC of fresh spotted tilapia fish samples was 6.3 × 106-8.8 × 108 cfu/g and TVC of samples of smoked spotted tilapia fish and the control were 2.0 × 104-6.4 × 104 cfu/g and 1.0 × 103-8.6 × 103 cfu/g, respectively. The mean L. monocytogenes count of fresh spotted tilapia fish samples was 1.3 × 102-2.4 × 102 cfu/g and that of samples of smoked spotted tilapia fish ranged from 1.6 × 101 to 23.1 × 101 cfu/g while samples of smoked spotted tilapia fish using convective smoking kiln showed no count for L. monocytogenes. The mean S. aureus count of fresh spotted tilapia fish samples ranged from 4.7 × 103 to 8.0 × 103 cfu/g and that of samples of smoked spotted tilapia fish ranged from 5.1 × 102 to 88.6 × 102 cfu/g and 1.1 × 102 to 3.8 × 102 cfu/g. The mean fat content (FC) count of samples of smoked spotted tilapia fish ranged from 1.1 × 101 to 6.0 × 101 cfu/g. S. paratyphi and E. coli were not detected in all smoked spotted tilapia fish samples. The study, however, concluded that the traditional drum smoked spotted tilapia fish could expose consumers to high microbial risk because of the presence of L. monocytogenes.

Research limitations/implications

– The fresh fish used in this study were obtained from coastal villages in Lagos State, and there were limitations in getting the samples in time to the processing centres and in preserving the fresh fish because of poor or non-availability of power (electricity).

Practical implications

– The paper includes implications for the development of a cost-effective smoked fish, to ensure food safety, enhanced health and improve the preservation and post-harvest losses of fresh fish.

Social implications

– The paper helps in developing an effective smoked method that will produce good-quality smoked fish, reduce the incidence of food poison and enhance the health of consumers.

Originality/value

– This research is of value to the traditional fish smokers and consumers. Smoked fish has been implicated as a source of microbial infection in Nigeria and West African sub-region in recent times and the need for good manufacturing practices cannot be overemphasized.

Effects of brine concentration on lipid oxidation and fatty acids profile of hot smoked tuna ( Thunnus albacares ) stored at refrigerated temperature

This work evaluated the lipid oxidation and the changes in fatty acids in hot-smoked tuna (Thunnus albacares) as a function of brine concentration. Fresh, commercially harvested tuna fish samples were purchased from a local supermarket. The fish were first immersed for 30 min in a brine solution at 5, 10, or 15% sodium chloride concentration and were then smoked at 50 °C for 3 h followed by 1 h at 60 °C and 3 h at 105 °C. The fish were then dried for 17 h, cooled and stored at 4 °C. Oxidative rancidity was measured by the peroxide value (PV), and thiobarbituric acid number (TBA) and fatty acids profile by GC-MS. Oxidative rancidity increased with storage time. The PV and TBARS values were more pronounced for samples immersed in 10% brine solution during the first 27 days of storage, whereas the lowest increase was observed for samples treated with 15% salt. Fatty acid concentration exhibited changes after smoking, and this was varied with salt concentration. The palmitic acid and stearic acid, the two main saturated fatty acids in tuna, increased after smoking at all brine concentration, whereas the contents of oleic acid, eicosapentaenoic acid and docosahexaenoic acid decreased. In conclusion, 15% NaCl-treated tuna gave smoked product with less lipid oxidation and a fatty acid profile comparable to that for 5 and 10% NaCl-treated samples.