Antioxidative Effect of Seaweed Extracts in Chilled Storage of Minced Atlantic Mackerel (Scomber scombrus): Effect on Lipid and Protein Oxidation

Plasma-activated water in combination with coconut exocarp flavonoids emerge as promising preservation technique for golden pompano: Impact of the treatment sequence

In the current study, the preservation effect of plasma-activated water (PAW), coconut exocarp flavonoids (CF) and their combination on golden pompano fillets during refrigerated storage was investigated with emphasize on the treating sequence. PAW effectively inactivated spoilage bacteria and inhibited total volatile basic nitrogen (TVB-N) increase, while boosted the TBARS and carbonyl values. PAW+CF exerted synergistic effect on extending the period before total bacterial count and TVB-N content reaching acceptance limit than PAW or CF alone (P < 0.05). In addition, their combined treatment effectively reduced fillets discoloration and texture deterioration. Simultaneously, lipid and protein oxidation were significantly inhibited, which was comparable to CF. It was indicated that the treatment sequence of PAW and CF profoundly impact the preservation effect. Specifically, prior CF marinating followed by PAW was more effective than the opposite sequence. Thus, combination of CF followed by PAW served as promising technique for fish fillets preservation.

Cryoprotective effect of soluble soybean polysaccharides and enzymatic hydrolysates on the myofibrillar protein of Nemipterus virgatus surimi

Cryoprotective effect and potential mechanism of soluble soybean polysaccharides (SSPS) and enzymatic hydrolysates on surimi was investigated. After hydrolysis, the molecular weight of SSPS significantly decreased, and the hydrolysates prepared by endo-polygalacturonase (EPG-SSPS) was the lowest (154 kDa). Infrared spectrum analysis revealed that enzymatic hydrolysis didn't alter the functional groups of SSPS, but it did augment the exposure to hydroxyl groups. Surimi containing 5 % EPG-SSPS had the lowest freezable water after 20 days of frozen storage. Furthermore, the 5 % EPG-SSPS group manifested the highest metrics in total sulfhydryl (8.0 × 10-5 mol/g), active sulfhydryl content (6.7 × 10-5 mol/g), Ca2+-ATPase activity, and exhibited the lowest level in carbonyl content, surface hydrophobicity (153 μg). Notably, the 5 % EPG-SSPS maintained the stability of protein structure. Conclusively, SSPS enzymatic hydrolysate using endo-polygalacturonase imparted superior cryoprotective effect on the myofibrillar protein of surimi, and the mechanism might be a decrease in molecular weight and exposure of hydroxyl groups.

Effects of chitosan-based packaging film crosslinked with nanoencapsulated star anise essential oil and superchilled storage on the quality of rabbit meat patties

In this paper, the effects of chitosan film containing star anise essential oil nanofiltration (CFSAO) and superchilled (SC) temperature on the changes of physicochemical and microbiological indexes of rabbit meat patties within 15 days of storage were studied. The total aerobic bacteria counts, malondialdehyde content, protein carbonyl content, total sulfhydryl content, and metmyoglobin content continued to grow throughout the entire experimental period, and the maximum absorption peak at the soret region of myoglobin gradually decreased. Along with the storage time extended, the brightness and redness of rabbit meat significantly decreased (P < 0.05), while the yellowness significantly increased (P < 0.05). The results of storage experiments showed that chitosan composite films and SC temperature had good inhibition on lipid oxidation, myoglobin oxidation and degradation, sulfhydryl content reduction, and microbial growth of rabbit meat after 15 days of storage, and could slow down the change of rabbit meat color.

A Recyclable Dipping Strategy to Stabilize Herring (Clupea harengus) Co-products During Ice Storage

Applying value-adding techniques to fish filleting co-products is rendered difficult due to their high susceptibility to lipid oxidation, microbial spoilage, and amine formation. In this study, a recyclable dipping strategy was developed and investigated for its ability to stabilize herring (Clupea harengus) co-products (head, backbone, caudal fin, intestines, belly flap, skin, and in some cases roe) against oxidation and microbial spoilage. From initial screening of seven antioxidative components/formulas in minced herring co-products during ice storage, an oil-soluble rosemary extract (RE-B) and isoascorbic acid (IAA) were identified as most promising candidates. These compounds were then formulated to a recyclable solution to be used for dipping of the herring co-products. The commercial Duralox MANC antioxidant mixture was used as a positive control. Dipping in 0.2% RE-B solution ± 0.5% IAA or in 2% Duralox MANC solutions remarkably increased the oxidation lag phase from < 1 day to > 12 days during subsequent storage on ice (0–1 °C) of minced or intact co-products, respectively, even when the antioxidant solutions were re-used up to 10 times. The dipping also reduced microbiological growth and total volatile basic nitrogen, but the effect became weaker with an increased number of re-using cycles. The presented dipping strategies could hereby facilitate more diversified end use of herring co-products from current fish meal to high-quality minces, protein isolates, or oils for the food industry.

Preservative Effect of Aqueous and Ethanolic Extracts of the Macroalga Bifurcaria bifurcata on the Quality of Chilled Hake (Merluccius merluccius)

This work addressed the preservative behaviour of different icing media containing extracts from the alga Bifurcaria bifurcata. A comparative study of the antimicrobial and antioxidant effects of aqueous and ethanolic extracts of this macroalga was carried out. Whole hake (Merluccius merluccius) pieces were stored in ice containing either kind of extract and analysed for quality changes throughout a 13-day storage period. A progressive loss of microbial and biochemical quality was detected in all batches as chilling time increased. A significant inhibitory effect (p < 0.05) on microbial activity could be observed as a result of including the aqueous (lowering of psychrotrophic and lipolytic counts and pH value) and ethanolic (lowering of psychrotrophic and lipolytic counts) extracts. Additionally, both kinds of extract led to a substantial inhibition (p < 0.05) in the lipid hydrolysis rate (formation of free fatty acids), greater in the case of the batch containing ethanolic extract. Concerning lipid oxidation, a similar inhibitory effect (p < 0.05) on the formation of secondary compounds (thiobarbituric acid substances) was noticed in fish specimens corresponding to both alga extracts; however, more (p < 0.05) peroxide formation was detected in fish corresponding to the ethanolic extract batch. A preservative effect can be concluded for both kinds of extract; this effect agrees with previous studies reporting the presence of hydrophilic and lipophilic bioactive compounds in B. bifurcata.

Sensory evaluation of fresh/frozen mackerel products: A review

Mackerel has received considerable attention in the global food market as one of the most important pelagic commercial fish species. The quality of mackerel is influenced by species, season, fishing area, nutritional status, catching method, handling, and storage. Due to the mackerel's perishability, its quality is mainly measured by sensory procedures. Although considerable effort has been made to explore quick and reliable quality analysis, developing a practical and scientific sensory evaluation of mackerel has been an active ongoing study area to meet the quality evaluation demand of the industry. Different sensory evaluation methods have been used to assess the mackerel fish quality, including Palatability and Spoilage test, Torry scheme, EU scheme, Quality Index Method, Catch damage index and Processed fish damage index, Affective test, Discriminative test, and Descriptive test. Each method has its strength and weakness. Despite mackerel sensory evaluation protocols having undergone partial harmonization, specific sample process needs to be carefully followed to minimize the change during sample preparation. This review summarizes the sensory evaluation methods in mackerel research, the factors affecting sensory evaluation, and then updates the latest advances in mackerel sensory evaluation and offers guidance for presenting its application in the mackerel chain. Also, each technique's advantages and limitations are discussed. In our opinion, the future trends for sensory evaluation of mackerel should be consumer-centric.

Influence of Refrigerated Storage on Water Status, Protein Oxidation, Microstructure, and Physicochemical Qualities of Atlantic Mackerel (Scomber scombrus)

Moisture migration, protein oxidation, microstructure, and the physicochemical qualities of Atlantic mackerel during storage at 4 °C and 0 °C were explored in this study. Three proton components were observed in mackerel muscle using low-field nuclear magnetic resonance relaxation, which were characterized as bound water, immobilized water, and lipid. The relaxation peak of immobilized water shifted to a shorter relaxation time and its intensity decreased with the proceeding of the storage process. T₁ and T₂ weighted images obtained by magnetic resonance imaging showed a slightly continuous decrease in the intensity of water. The significant decrease in sulfhydryl (SH) content and the increase in carbonyl group (CP) content, disulfide bond content, and hydrophobicity revealed the oxidation of protein during storage. The contents of α-helixes in proteins decreased while that of random coils increased during storage, which suggested changes in the secondary structure of mackerel protein. The storage process also caused the contraction and fracture of myofibrils, and the granulation of endolysin protein. In addition, the drip loss, total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBARS) value, and b* value increased significantly with the storage time.

Improving the Stability of Red Blood Cells in Rainbow Trout (Oncorhynchus mykiss) and Herring (Clupea harengus): Potential Solutions for Post-mortem Fish Handling to Minimize Lipid Oxidation

This study aimed at limiting hemolysis of fish red blood cells (RBCs) as a strategy to limit hemoglobin (Hb)-induced lipid oxidation during post-mortem handling and processing. Effects of varying temperature, salinity, and mechanical impact were studied using washed resuspended RBCs (wr-RBCs) and whole blood (WB) from rainbow trout (Oncorhynchus mykiss) and herring (Clupea harengus). The wr-RBCs were most stable avoiding mechanical stress, keeping isotonic conditions (0.9–1.3% NaCl) and low temperature 0–6 °C, with predicted minimum at 2.5 °C. When compared at the same salinity, it was found that hemolysis was more pronounced in herring than trout wr-RBCs. Furthermore, WB was more stable than wr-RBCs, showing protecting the effects of blood plasma. Studying individual plasma components, stabilizing effects were found from glucose, proteins, and ascorbic acid. This study indicates that small adjustments in the early handling and processing of fish such as changing salinity of storage and rinsing solutions could minimize Hb contamination of the fish muscle and thereby improve quality.

Source, Extraction, Characterization, and Applications of Novel Antioxidants from Seaweed

Driven by a general demand for clean labels on food and cosmetic products, these industries are currently searching for efficient natural antioxidants to replace synthetic antioxidants. Seaweed contains several compounds with antioxidative properties (phlorotannins, pigments, tocopherols, and polysaccharides). It is possible to extract these compounds via different extraction techniques, which are discussed in this review. Among the abovementioned compounds, phlorotannins are probably the most important in terms of the antioxidative potential of seaweed extracts. We review how the different antioxidative compounds can be characterized. We discuss the current knowledge of the relationship between phlorotannin's structure and antioxidant properties in in vitro studies as well as in food systems. Concerning food systems, most studies on the antioxidative effect of seaweed extracts have been performed with extracts prepared from Fucus vesiculosus, despite the fact that this species is less available than other species, such as Ascophyllum nodosum, which also has high phlorotannin content.

Effect of 6-gingerol on physicochemical properties of grass carp (Ctenopharyngodon idellus) surimi fortified with perilla oil during refrigerated storage

BACKGROUND

Surimi is produced from deboned fish muscle through washing to remove blood, lipids, sarcoplasmic proteins and other impurities. There is an increasing interest in the fortification of surimi with ω-3 polyunsaturated fatty acids because of their health benefits. However, lipid oxidation should be considered as an important factor during storage. Hence, in this study, the quality properties and oxidative stability of surimi fortified with 30 g kg^-1 perilla oil (PO), or 5 g kg^-1 6-gingerol (GI) or their combination (PO+GI) was investigated.

RESULTS

Perilla oil significantly improved whiteness of surimi gel, but negatively influenced its gel strength, water holding capacity (WHC) and texture. However, there was no significant difference in texture properties among GI, PO+GI and control groups. During the whole storage period, GI and PO+GI groups had higher gel strength and WHC than control and PO groups. Moreover, lower thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N), carbonyl content and total plate count (TPC) were observed in GI group compared with other groups.

CONCLUSION

Perilla oil and 6-gingerol could be applied together to effectively fortify surimi qualities. Additionally, 6-gingerol could prevent lipid and protein oxidation and microbial growth of surimi during refrigerated storage. © 2017 Society of Chemical Industry.