Oxidative stability, volatile components and polycyclic aromatic hydrocarbons of cold-smoked sardine (Sardina pilchardus) and dolphinfish (Coryphaena hippurus)

Recent advances on characterization of protein oxidation in aquatic products: A comprehensive review

In addition to microbial spoilage and lipid peroxidation, protein oxidation is increasingly recognized as a major cause for quality deterioration of muscle-based foods. Although protein oxidation in muscle-based foods has attracted tremendous interest in the past decade, specific oxidative pathways and underlying mechanisms of protein oxidation in aquatic products remain largely unexplored. The present review covers the aspects of the origin and site-specific nature of protein oxidation, progress on the characterization of protein oxidation, oxidized proteins in aquatic products, and impact of protein oxidation on protein functionalities. Compared to meat protein oxidation, aquatic proteins demonstrate a less extent of oxidation on aromatic amino acids and are more susceptible to be indirectly oxidized by lipid peroxidation products. Different from traditional measurement of protein carbonyls and thiols, proteomics-based strategy better characterizes the targeted oxidation sites within proteins. The future trends using more robust and accurate targeted proteomics, such as parallel reaction monitoring strategy, to characterize protein oxidation in aquatic products are also given.

Combination of Freezing, Low Sodium Brine, and Cold Smoking on the Quality and Shelf-Life of Sea Bass (Dicentrarchus labrax L.) Fillets as a Strategy to Innovate the Market of Aquaculture Products

Simple Summary

The growing fish consumption driven by the increased production, the concomitant reduction in wastage, and the huge amount of fish food traded globally, makes it important to address the sustainability, profitability, security, and safety issues related to the seafood production sector. Toward this direction, innovative methods extending shelf-life, maintaining seafood quality, safety and nutritional characteristics and that open new market opportunities, satisfy consumer preferences, and improve product traceability are required. Answering this call, this study aimed to develop a new value added product exploiting a species largely cultured in Italy (i.e., European sea bass). In particular, sea bass fillets were cold smoked using both fresh and frozen fillets to understand the effectiveness of this kind of processing on developing a new fish product and whether the quality of the raw material that could be affected by freezing and thawing could change the quality of the final product. It was seen that the quality of the raw material was affected by the time of frozen storage and that these starting conditions consequently impaired the quality of the smoked fillets. However, cold smoking was proven to be an effective process to develop a valuable product contributing to the growth of the aquaculture sector.

Abstract

Aquaculture is playing a leading role in both meeting the growing demand for seafood and increasing the sustainability of the fish production sector. Thus, innovative technologies that improve its sustainability, competitiveness, and safety are necessary for growth in the sector. This study aimed to develop cold smoked sea bass fillets from aquaculture. The aptitude of frozen and fresh fillets for cold smoking was investigated by processing both fresh and thawed fillets kept previously at −20 °C for 15, 30, 60, and 90 days. Moreover, to develop a low-salt product, fillets were immersed in low-sodium or standard brine. Sensory, biochemical, and physical-chemical analyses were performed on both the raw fillets and the smoked fillets during vacuum packaged storage for 35 days at 1 ± 0.5 °C. Young modulus values, representative of texture and sensory evaluation, showed that the quality of fresh fillets was better compared to the thawed ones, thus affecting the quality of the final product as the correlation between parameters showed (principal component analysis). Cold smoking was effective in both maintaining the total volatile basic nitrogen (TVB-N) below the threshold for spoilage and preventing lipid peroxidation. Moreover, partial sodium replacement by potassium did not alter the sensory attributes of smoked fillets, which maintained high scores up to 21 days.

Characterization of the physicochemical changes and volatile compound fingerprinting during the chicken sugar-smoking process

Sugar-smoking contributes to improving flavor attributes of meat products. However, there is rather limited information concerning the relationship between sugar-smoking process parameters and volatile compound (VC) fingerprinting as well as related quality attributes of sugar-smoked chicken. In this work, the changes in VC across the whole sugar-smoking process were determined and analyzed and physicochemical properties, free fatty acid, thiobarbituric acid reactive substances values, and E-nose were also performed to characterize the quality properties of sugar-smoked chicken breast (CB) and chicken skin (CS). Results suggested that a higher amount (P < 0.05) of total VC was observed in CS compared with CB during the whole processing, which may be correlated with higher thiobarbituric acid reactive substances values, and higher polyunsaturated fatty acid/saturated fatty acid ratio. According to E-nose analysis, the volatile flavor is clearly separated in the sugar-smoking stage. Volatile fingerprinting results revealed that heterocycles were the characteristic flavor formed during sugar-smoking process and hexanal, nonanal, furfural, 5-methyl-2-furancarboxaldehyde, and 2-acetyl-5-methylfuran were the major volatiles of the CS, which was closely related to lipid oxidation and caramelization reaction. Above all, the flavor of sugar-smoked chicken was mainly derived from CS and sugar-smoked process improved the flavor of CS. This study could provide theoretical guidance for regulation of the color and flavor of sugar-smoked chicken and further promote the development of the industry.

Review of polycyclic aromatic hydrocarbons (PAHs) in fish and fisheries products; a Sri Lankan perspective

Polycyclic aromatic hydrocarbons (PAHs) are emerging as important contaminants in smoked and smoke-dried fish and fish products. The smoking techniques and different parameters contribute to the PAH load in smoked fish. This review paper provides insight into the PAHs and their sources and pathways to fish, effects on human health, smoking parameters and PAHs, regulations, available information, gaps in present knowledge, and future prospects in smoked fish from Sri Lanka. Based on the very few available research reports on PAH levels in smoked fish from Sri Lanka, it is concluded that the smoked fish are not safe for human consumption according to the regulation limits published by the European Union (EU). It is therefore important to implement proper guidelines and produce a safe product to ensure that hazards are managed as appropriate Hazard Analysis and Critical Control Points (HACCP). Graphical abstract.

The combined impact of cold smoking and natural antioxidants on quality and shelf life of dolphinfish (Coryphaena hippurus) fillets

This study aimed to produce new value-added products from dolphinfish (Coryphaena hippurus) as fillets when using cold smoking combined with natural antioxidants, obtained from Halocnemum strobilaceum a plant belonging to halophytes. The fillet treatments were controlled (untreated), immersed in standard brine (STD), treated with NaCI and antioxidant before freezing (Aox-pre) and treated with NaCl and antioxidant after thawing (Aox-post). The quality of dolphinfish fillets was assessed using sensory, biochemical, microbiological, and technological parameters. Treating fillets with antioxidants before freezing and cold smoking (Aox-pre) enhanced significantly the shelf life, as well as improved the biochemical, microbiological, and sensory aspects of the product. Aox-pre fillets had the lowest peroxide values (PV) and malondialdehyde (MDA) content, demonstrating that the immediate treatment of fillets with the polyphenols protected lipids from peroxidation. The smoking process, together with antioxidant treatment, significantly reduced microbial counts after 15 days of storage, compared to the control. Overall, combining antioxidant treatments with cold smoking has a positive effect on the quality of Aox-pre fillets with respect to both sensory components and biochemical parameters associated with shelf life. Consequently, Aox-pre treatment enhances the marketability of this species, promoting local and seasonal products, contributing to costal fisheries sustainability.

Distribution, characterization, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Ovia River, Southern Nigeria

The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water, sediment, and fish (Clarias gariepinus) samples from Ovia River, Southern Nigeria, were evaluated, to assess the contamination profile, dietary intake, and human health risks associated with exposure. Results showed that naphthalene, acenaphthylene, and fluoranthene were the most dominant contaminant in water, sediment, and fish, respectively, with mean concentrations (μg/L) of 3.08, 45.4, and 90.7. Spatial distribution showed high occurrence of PAHs in Ekenwan, the downstream station, for all the matrices. Source identification using multivariate analysis revealed mixed patterns of pyrogenic and petrogenic origins. Estimated daily intake (EDI) of PAHs through fish consumption ranged from 2.18 × 10^-7 to 5.23 × 10^-5 mg/kg/day; values were however lower than the reference dose (RfD) indicating low risk. Estimated values for hazard quotients (HQs) and hazard index (HI) for both non-carcinogenic and carcinogenic risks were below 1 indicating low risk through dietary and non-dietary exposure to water, sediment, and fish from Ovia River. However, estimated HI values for direct ingestion of sediment were above 1, indicating the possibility of non-carcinogenic health risk from exposure. Carcinogenic risk indices also indicated low risk from fish consumption. In spite of the assessed low risk from exposure, continuous monitoring of PAH levels in this water body is imperative to prevent future human health effects.

Effect of curing ingredients and vacuum packaging on the physico-chemical and storage quality of ready-to-eat Vawksa rep (smoked pork product) during refrigerated storage

AIM

The present study was conducted for the development of ready-to-eat Vawksa rep (smoked pork product) and to study the synergistic effect of curing ingredients and vacuum packaging on the physico-chemical and storage quality during refrigerated storage at (4°C±1°C) for 15 days.

MATERIALS AND METHODS

Four different batches of Vawksa rep samples were prepared, i.e., T-1 (uncured, first cooked at 121°C for 15 min, and then smoked at 120°C for 30 min), T-2 (uncured, cooked, and smoked simultaneously at 120°C for 45 min), T-3 (cured, first cooked at 121°C for 15 min, and then smoked at 120°C for 30 min), and T-4 (cured, cooked, and smoked simultaneously at 120°C for 45 min).

RESULTS

Cooking yield was significantly higher (p<0.05) for the T-4. The pH of T-3 and T-4 samples was significantly higher (p<0.05) on day 15. The tyrosine value of all the samples increased significantly (p<0.05) among the different days of analysis. Thiobarbituric acid value was significantly (p<0.05) lower in T-3 sample both at the beginning and at the end of storage period. In microbiological profile, total plate count was lower in T-3 and T-4 than T-1 and T-2. However, Escherichia coli count was negative for T-3 and T-4 samples throughout the storage period. Among sensory attributes, T-3 and T-4 samples registered superior scores for color, flavor, texture, juiciness, and overall acceptability.

CONCLUSION

Furthermore, Vawksa rep (smoked pork product) could be prepared easily with little technology up-gradation and with a negligible escalation of production cost.

The effect of combined traditional and novel treatments on oxidative status of dolphinfish (Coryphaena hippurus) and sardine (Sardina pilchardus) muscle lipids

Fish is rich in polyunsaturated fatty acids with beneficial effects on human health; however, these lipids are very sensitive to auto-oxidation reactions, leading to loss of nutritional and sensory quality. The effect of traditional (brining, smoking) and novel (addition of polyphenolic extracts, high pressure) preservation processes on the antioxidant/oxidative status of muscle lipids from dolphinfish and sardine was studied. Brining with oregano or rosemary aqueous extracts, as well as smoking, gave rise to deposition of phenolic compounds (9–42, 1.5–4.5 and 0.4–2.3 µg phenol/g for smoked, oregano-brined and rosemary-brined samples, respectively) in the muscle of both fish species. The antioxidant activity, as measured by ferric reducing ability, was also improved after brining with antioxidant extracts or smoking, results ranging from 8.9 to 82 mM FeSO4 · 7H2O equivalents/mg muscle depending on the treatment and the fish species. Consequently, fish lipid oxidation (as measured by thiobarbituric acid reactive substances) derived from brining and pressurizing, applied alone or in combination, was reduced between 6.6 and 69.8% depending on the treatment and the fish species. The combination of brining with oregano extract and light smoking showed an additional antioxidant effect, as compared with that obtained by smoking, on reducing sardine lipid oxidation derived from brining and pressurizing.