Simultaneous determination of multiple quality indices of dried shrimp (Parapenaeopsis hardwickii) during storage using Raman spectroscopy.

BACKGROUND: Dried shrimp is a high-value fishery product worldwide, but rapid and accurate assessment of its quality remains challenging. In the present study, a new method based on Raman spectroscopy was developed for assessing the quality changes in dried shrimp (Parapenaeopsis hardwickii) during storage. RESULTS: A high-quality Raman spectrum of astaxanthin (AST) was obtained from the third abdominal segment of dried shrimp. The intensity ratio (I1520/I1446) of the band from 1520 cm-1 to that at 1446 cm-1, which was ascribed to AST and protein/lipid, respectively, was calculated. I1520/I1446 can probe AST degradation in dried shrimp during storage at both 37 and 4 °C and further reflect quality changes of dried shrimp, as indicated by indices including total volatile basic nitrogen, pH and thiobarbituric acid reactive substances. CONCLUSION: Compared to conventional methods, the proposed method avoids complex and time-consuming preprocessing and provides significant advantages including cost-effectiveness and rapid detection. © 2024 Society of Chemical Industry.

Recent progress in fish oil-based emulsions by various food-grade stabilizers: Fabrication strategy, interfacial stability mechanism and potential application.

Fish oil, rich in a variety of long-chain ω-3 PUFAs, is widely used in fortified foods due to its broad-spectrum health benefits. However, its undesired characteristics include oxidation sensitivity, poor water solubility, and fishy off-flavor greatly hinder its exploitation in food field. Over the past two decades, constructing fish oil emulsions to encapsulate ω-3 PUFAs for improving their physicochemical and functional properties has undergone great progress. This review mainly focuses on understanding the fabrication strategies, stabilization mechanism, and potential applications of fish oil emulsions, including fish oil microemulsions, nanoemulsions, double emulsions, Pickering emulsions and emulsion gels. Furthermore, the role of oil-water interfacial stabilizers in the fish oil emulsions stability will be discussed with a highlight on food-grade single emulsifiers and natural complex systems for achieving this purpose. Additionally, its roles and applications in food industry and nutrition field are delineated. Finally, possible innovative food trends and applications are highlighted, such as novel fish oil-based delivery systems construction (e.g., Janus emulsions and nutraceutical co-delivery systems), exploring digestion and absorption mechanisms and enhancing functional evaluation (e.g., nutritional supplement enhancer, and novel fortified/functional foods). This review provides a reference for the application of fish oil-based emulsion systems in future precision diet intervention implementations.

Rapid and non-destructive freshness evaluation of squid by FTIR coupled with chemometric techniques.

BACKGROUND: Freshness is an important quality of squid with respect to determining the market price. The methods of evaluation of freshness fail to be widely used as a result of the lack of rapidity and quantitation. In the present study, a rapid and non-destructive quantification of squid freshness by Fourier transform infrared spectroscopy (FTIR) spectra combined with chemometric techniques was performed. RESULTS: The relatively linear content change of trimethylamine (TMA-N) and dimethylamine (DMA-N) of squid during storage at 4 °C indicated their feasibility as a freshness indicator, as also confirmed by sensory evaluation. The spectral changes were mainly caused by the degradation of proteins and the production of amines by two-dimensional infrared correlation spectroscopy, among which TMA-N, DMA-N and putrescine were the main amines. The successive projections algorithm (SPA) was employed to select the sensitive wavenumbers to freshness for modeling prediction including partial least-squares regression, support vector regression (SVR) and back-propagation artificial neural network. Generally, the SPA-SVR model of the selected characteristic wavenumber showed a higher prediction accuracy for DMA-N (R2 P  = 0.951; RMSEP  = 0.218), whereas both SPA-SVR (R2 P  = 0.929; RMSEP  = 2.602) and Full-SVR (R2 P  = 0.941; RMSEP  = 2.492) models had a higher predictive ability of TMA-N. CONCLUSION: The results of the present study demonstrate that FTIR spectroscopy coupled with multivariate calibration shows significant potential for the prediction of freshness in squid. © 2021 Society of Chemical Industry.

Gel-type emulsified muscle products: Mechanisms, affecting factors, and applications.

The gel-type emulsified muscle products improve fatty acid composition, maintain the oxidative stability, and achieve a better sensory acceptability. This review emphasizes the stabilization mechanisms of these emulsified muscle products. In particular, factors associated with the stability of the emulsified muscle systems are outlined, including the processing conditions (pH and heating), lipids, and emulsifiers. Besides, some novel systems are further introduced, including the Pickering emulsions and organogels, due to their great potential in stabilizing emulsified gels. Moreover, the promising prospects of emulsion muscle products such as improved gel properties, oxidative stability, freeze-thaw stability, fat replacement, and nutraceutical encapsulation were elaborated. This review comprehensively illustrates the considerations on developing gel-type emulsified products and provides inspiration for the rational design of emulsified muscle formulations with both oxidatively stable and organoleptically acceptable performance.

Diversity and succession of the microbial community and its correlation with lipid oxidation in dry-cured black carp (Mylopharyngodon piceus) during storage.

This study aimed to achieve deeper insights into the microbiota composition and dynamic succession of the dry-cured black carp during storage using a high-throughput sequencing technique (HTS). The effect of lipid oxidation on microorganisms was also evaluated. Over 651 bacterial genera belonging to 37 phyla were identified. Firmicutes, Proteobacteria and Actinobacteria were the main bacterial phylum, some are highly associated with meat spoilage. Staphylococcus, Macrococcus and Acinetobacter were the most three microbial genera throughout the entire storage period (30 days). Between two different storage temperature, refrigeration at 4 °C could facilitate maintaining the microbial diversity, while 25 °C storage led to the formation of dominant microflora and the reduction of community diversity. Canonical correspondence analysis (CCA) showed that acid value (AV), malondialdehyde (MDA) and 4-hydroxy-2-hexenal (HHE) contents were three key environmental factors (oxidation products) affecting the profile of the microbiota. Staphylococcus presented a positive correlation with HHE content, while Macrococcus and Acinetobacter were negatively correlated with HHE content. These results could expand our knowledge on the effect of lipid oxidation on change of microbial distribution, it could also present an guideline to develop advanced storage methods for the vacuum packed dry-cured fish products.

ß-Cyclodextrin-/AuNPs-functionalized covalent organic framework-based magnetic sorbent for solid phase extraction and determination of sulfonamides.

ß-Cyclodextrin-functionalized magnetic covalent organic framework (Fe3O4@COF@Au-ß-CD) was developed as sorbent for magnetic solid phase extraction of trace sulfonamides in meat samples prior to HPLC-MS/MS analysis. The sorbent was synthesized by loading gold nanoparticles onto a Fe3O4@COF surface and then functionalized by thiolated-ß-cyclodextrin immobilization via Au-S bonding formation. The prepared composite material was employed for sulfonamides extraction. The main parameters were optimized to obtain the best extraction efficiency. The experiments of adsorption kinetics were carried out to investigate the adsorption mechanism. Results showed the pseudo-second-order kinetic was better fitted with the adsorption kinetics of sulfonamides. Under optimized conditions, the magnetic solid phase extraction-HPLC method showed good linearity (R2 ≥ 0.9936), and the limits of detection were in the range of 0.8-1.6 µg kg-1. The proposed method was successfully used for quantitation of sulfonamides in real samples. The recoveries ranged from 78.9 to 112.0% with relative standard deviations (RSDs) < 10% (n = 5). The proposed method exhibited great potential for enrichment and determination of sulfonamides in many other food or environment samples. Graphical abstract.

Effects of Oil Droplet Size and Interfacial Protein Film on the Properties of Fish Myofibrillar Protein-Oil Composite Gels.

The effects of oil droplet size and the formation of an interfacial protein film (IPF) on silver carp myofibrillar protein (MP)-oil composite gels were studied. MP- or Tween 80-stabilized camellia seed oil emulsions with different droplet sizes were prepared and added to MPs to prepare composite gels. The oil droplet size of the Tween 80-stabilized emulsion was significantly smaller (p < 0.05) than that of the MP-stabilized emulsion with the same homogenization speed. However, polymerization of Tween 80-stabilized emulsions during the preparation of the composite gels was found. Composite gels with the MP-stabilized emulsions of a small droplet size showed significantly improved water-holding capacity, texture, and dynamic rheological properties. Interfacial shear rheology studies revealed that the storage modulus (G') of the MP-stabilized emulsion composite gels was higher than that of the Tween 80-stabilized gels, and the tan δ of the MP-stabilized oil emulsion composite gels was smaller than that of the Tween 80-stabilized gels, indicating that stronger elastic gel structures were formed. These results suggested that the IPF formed in the MP-stabilized emulsion helped stabilize the oil droplets embedded in the protein gel network, and the smaller the droplet size, the more stable the composite gel. This work provides a better understanding of how oil emulsions interact with protein and affect the properties of MP-oil composite gels.

Typical reactive carbonyl compounds in food products: Formation, influence on food quality, and detection methods.

Reactive carbonyl compounds are a large group of highly reactive electrophilic compounds containing one or more carbonyl groups, which can be created by lipid oxidation both in vivo and in food. Malondialdehyde (MDA) and 4-hydroxy-2-nonenel (HNE) are the two most important reactive carbonyl compounds in food. They can react with proteins and nucleic acids and cause biological damage to cells and lead to carbonyl stress. Therefore, they are regarded as representative products of lipid oxidation, toxic molecules, and biomarkers of oxidative stress. Apart from biological toxicity, they can also react with myoglobin and myofibrillar protein and further affect color, gel properties, hydrophobicity, or other properties of food. However, the effects of MDA and HNE on food qualities have not received as much attentions and it is noteworthy that the existing analytical methods for detecting MDA and HNE have a variety of limitations due to the complexity of food samples. To provide a comprehensive understanding of HNE and MDA, the formation mechanism, occurrence, and analytical methods for MDA and HNE in food matrix were summarized in this article. Emphasis is focused on formation mechanism including non-enzymatic pathway and enzymatic pathway, and detection methods including the extraction methods, the new development of sample pre-treatment technology and the selection of derivative reagents. Impressively, the reaction mechanism of MDA and HNE with myoglobin or myofibrillar protein is also described to explain how MDA and HNE affect food quality.

HPLC determination of γ-aminobutyric acid and its analogs in human serum using precolumn fluorescence labeling with 4-(carbazole-9-yl)-benzyl chloroformate.

In this study, a simple analytical method for the determination of γ-aminobutyric acid, gabapentin, and baclofen by using high-performance liquid chromatography with fluorescence detection was developed. An amidogen-reactive fluorescence labeling reagent, 4-(carbazole-9-yl)-benzyl chloroformate was first used to sensitively label these analytes. The completed labeling of these analytes can be finished rapidly only within 5 min at the room temperature (25°C) to form 4-(carbazole-9-yl)-benzyl chloroformate labeled fluorescence derivatives. These labeled derivatives expressed strong fluorescence property with the maximum excitation and emission wavelengths of 280 and 380 nm, respectively. The labeled derivatives were analyzed using a reversed-phase Eclipse SB-C18 column within 10 min with satisfactory shapes. Excellent linearity (R2  > 0.995) for all analytes was achieved with the limits of detection and the limits of quantitation in the range of 0.25-0.35 and 0.70-1.10 µg/L, respectively. The proposed method was used for the simultaneous determination of γ-aminobutyric acid and its analogs in human serum with satisfactory recoveries in the range of 94.5-97.5%.

Probucol promotes high glucose-induced proliferation and inhibits apoptosis by reducing reactive oxygen species generation in Müller cells.

PURPOSE: To explore the protective effect of probucol on human retinal Müller cells cultured in high glucose. METHODS: Primary Müller cells from human retinas were cultured in complete DMEM. Third-generation Müller cells were identified using glutamine synthetase (GS) antibody and randomly divided into three groups: normoglycemia (NG, 5.5 mmol/L); hyperglycemia (HG, 30 mmol/L); and hyperglycemia (30 mmol/L) with probucol (10 µmol/L; HGPB). After a 24-h intervention, cell proliferation, apoptosis, and cellular reactive oxygen species (ROS) were measured with a CCK-8 kit, flow cytometry, and DCFH-DA probe, respectively. Kelch-like ECH-associated protein 1 (Keap1), NF-E2-related factor 2 (Nrf2), and glutamate cysteine ligase catalytic subunit (GCLC) protein expression were detected by immunofluorescence staining. RESULTS: For NG, HG, and HGPB, optical density (OD) values for cell proliferation were 0.98 ± 0.23, 0.58 ± 0.11, and 0.73 ± 0.11; apoptotic rates were 2.79 ± 0.52%, 7.70 ± 0.44%, and 4.00 ± 0.95%; and intracellular ROS were 20.89 ± 5.14, 55.17 ± 14.07, and 26.28 ± 4.73, respectively. Compared to NG, OD was markedly decreased (P < 0.01), apoptosis was increased (P < 0.001), and intracellular ROS level was significantly higher than in HG (P < 0.01). Compared to HG, OD was markedly increased (P < 0.01), apoptosis was meaningfully decreased (P < 0.01), and intracellular ROS level was significantly lower than in HGPB (P < 0.01). GS, Keap1, Nrf2, and GCLC had positive expression. CONCLUSIONS: Probucol could inhibit intracellular ROS generation, promote proliferation, and decrease apoptosis of human retinal Müller cells cultured in high glucose. This might also be associated with Keap1/Nrf2/ARE oxidative stress signaling pathway activation.

Antimicrobial effect and mechanism of cinnamon oil and gamma radiation on Shewanella putrefaciens.

The aims of this study were to observe the antimicrobial effect and mechanism of cinnamon oil combined with gamma radiation on Shewanella putrefaciens. Gamma radiation increased the antimicrobial activity of cinnamon oil, and the relative radiation sensitivity of gamma radiation on S. putrefaciens was increased by cinnamon oil. Gamma radiation significantly increased the changes of bacterial morphology, intra-adenosine 5'-triphosphate (intra-ATP) and extra-ATP concentrations and pHin value of S. putrefaciens treated cinnamon oil. Although, gamma radiation used alone didn't damage the bacterial morphology and ATP concentrations significantly. Gamma radiation assisted cinnamon oil to damage the cell permeability and integrity of S. putrefaciens, thus the combination of cinnamon oil and gamma radiation showed a better antimicrobial activity than used alone.

Effect of slaughter methods on the quality of Chilean jack mackerel (Trachurus murphyi) during refrigerated storage.

The main objective of this study was to assess the influence of slaughter methods on the quality of Chilean jack mackerel (Trachurus murphyi) during refrigerated storage on board. Fishes were slaughtered by asphyxia in air (AA), asphyxia in ice water (AI) or stunning fish heads (SH), and the rigor mortis, pH, total volatile basic nitrogen (TVB-N), trimethylamine (TMA), 2-thiobarbituric acid reactive substances (TBARS) and sensory properties for the fishes were analyzed. On day 0, Chilean jack mackerel samples of AI group displayed higher pH values than those of AA and SH groups. TVB-N, TMA and TBARS values of all samples increased with the storage time, and these values of AI had a lower increase than AA and SH. Moreover, samples of AI had a better sensory score than AA and SH during storage. It can be concluded that slaughter method of asphyxia in ice water for Chilean jack mackerel exhibit the better efficiency on maintaining the fish quality during refrigerated storage on board.

Enhanced probiotic viability in innovative double-network emulsion gels: Synergistic effects of the whey protein concentrate-xanthan gum complex and κ-carrageenan.

In this study, the whey protein concentrate and xanthan gum complex obtained by specific pH treatment, along with κ-carrageenan (KC), were used to encapsulate Lactobacillus acidophilus JYLA-191 in an emulsion gel system. The effects of crosslinking and KC concentration on the visual characteristics, stability, mechanical properties, and formation mechanism of emulsion gels were investigated. The results of optical imaging, particle size distribution, and rheology exhibited that with the addition of crosslinking agents, denser and more homogeneous emulsion gels were formed, along with a relative decrease in the droplet size and a gradual increase in viscosity. Especially when the concentration of citric acid (CA) was 0.09 wt%, KC was 0.8 wt%, and K+ was present in the system, the double-network emulsion gel was stable at high temperatures and in freezing environments, and the swelling ratio was the lowest (9.41%). Gastrointestinal tract digestive treatments and pasteurization revealed that the probiotics encapsulated in the double-network emulsion gel had a higher survival rate, which was attributed to the synergistic cross-linking of CA and K+ biopolymers to construct the emulsion gels. Overall, this study highlights the potential of emulsion gels to maintain probiotic vitality and provides valuable insights for developing inventive functional foods.

Insight into flavor changes in bighead carp (Aristichthys nobilis) fillets during storage based on enzymatic, microbial, and metabolism analysis.

The flavor alterations in bighead carp subjected to varying storage temperatures and the underlying metabolic mechanism were elucidated. Analysis of volatile flavor compounds, electronic nose, free amino acids, ATP-related compounds, and sensory evaluations uncovered a progressive flavor deterioration during storage, especially at 25 °C. Metabolomics-based flavor relating component profiling analysis showed that free fatty acids formed various fatty aldehydes including (E, E)-2,4-heptadienal and nonanal under lipoxygenase catalysis. Alcohol dehydrogenase and alcohol acyltransferases were intimately involved in alcohol and ester generation, while alkaline phosphatase, 5'-nucleotidase, and acid phosphatase were closely associated with IMP, Hx, and HxR conversion, respectively. Aeromonas, Serratia, Lactococcus, Pseudomonas, and Peptostreptococcus notably influenced flavor metabolism and enzyme activities. The metabolism disparities of valine, leucine, isoleucine, lysine, and α-linolenic acid could be the primary factors contributing to flavor metabolism distinctions. This study offers novel insights into the flavor change mechanisms and potential regulation strategies of bighead carp during storage.

Mechanisms underlying the potent antimicrobial effects of plasma-activated seawater (PASW) on fish spoilage bacterium Shewanella putrefaciens.

Plasma-activated seawater (PASW) presents a promising approach for marine fish preservation, yet its antimicrobial efficacy and mechanisms remain unclear. This study found that PASW exhibits superior bactericidal properties against the fish spoilage bacterium Shewanella putrefaciens compared to plasma-activated water (PAW), and increased effectiveness in preserving fish fillets. To clarify the mechanisms, a detailed investigation was conducted, including the generation of reactive oxygen/nitrogen species (ROS/RNS) and active halogen species in PASW, and their antimicrobial efficacy. Findings showed greater nitrite and hydrogen peroxide production in PASW relative to PAW, as well as the conversion of chloride/bromide ions into active species, which collectively enhanced PASW's antimicrobial activity. The synergistic action of ROS/RNS and active chlorine/bromine species in PASW promoted the generation of intracellular ROS, causing increased membrane damage, redox imbalance, and consequently higher bacterial mortality. This study enhances our understanding of PASW's antimicrobial effects and highlights its potential applications in the seafood industry.

Integration of lanthanide MOFs/methylcellulose-based fluorescent sensor arrays and deep learning for fish freshness monitoring.

Preserving fish meat poses a significant challenge due to its high protein and low fat content. This study introduces a novel approach that utilizes a common type of lanthanide metal-organic frameworks (Ln-MOFs), EuMOFs, in combination with 5-fluorescein isothiocyanate (FITC) and methylcellulose (MC) to develop fluorescent sensor arrays for real-time monitoring the freshness of fish meat. The EuMOF-FITC/MC fluorescence films were characterized with excellent fluorescence response, ideal morphology, good mechanical properties, and improved hydrophobicity. The efficacy of the fluorescence sensor array was evaluated by testing various concentrations of spoilage gases (such as ammonia, dimethylamine, and trimethylamine) within a 20-min timeframe using a smartphone-based camera obscura device. This sensor array enables the real-time monitoring of fish freshness, with the ability to preliminarily identify the freshness status of mackerel meat with the naked eye. Furthermore, the study employed four convolutional neural network (CNN) models to enhance the performance of freshness assessment, all of which achieved accuracy levels exceeding 93 %. Notably, the ResNext-101 model demonstrated a particularly high accuracy of 98.97 %. These results highlight the potential of the EuMOF-based fluorescence sensor array, in conjunction with the CNN model, as a reliable and accurate method for real-time monitoring the freshness of fish meat.

Effect of microwave (MW)-subcritical extraction on oil recovery, oxidative stability, and lipid types from Katsuwonus pelamis livers.

Katsuwonus pelamis is a tuna species mostly sold for canned fillets, its livers were lack of utilization. This study thus investigated an oil production method combining microwave (MW) pretreatment and subcritical dimethyl ether (SDME) in aim to reach improved efficiency and oil quality. The heating characteristics from different MW powers (400, 600, and 800 W) were evaluated, and SEM showed MW having hydrolysis effect on matrix lipoprotein, the fortified recovery rate was also found. Under the MW-SDME condition with 600 W power, 1:5 solid-to-liquid ratio, and 100 min, the recovery reached 93.21% in maximal (SDME ∼50%). To further improve quality, MW powers was noticed affecting lipid types, fatty acid composition, and oxidative stability of produced oils. 1286 lipid types (mostly glyceride and phospholipid-type) were identified, while higher MW lowered the emulsifying phospholipids prompting phase separation. Several oxidation indexes consistently increased with the rising MW power, GC-MS suggested 400 W for higher DHA.

Thermal aging of polystyrene microplastics within mussels (Mytilus coruscus) under boiling and drying processing.

Aged microplastics (MPs) in the environment are a growing concern due to their higher ecological toxicity compared to pristine MPs. While previous studies have explored aging behaviors of MPs under various stress conditions, little is known about their aging during food processing. In this study, we investigated the effects of different thermal food processing methods on the aging of polystyrene (PS) MPs within mussels. We subjected the mussels containing PS MPs to boiling, boiling/solar drying, boiling/hot air drying, and boiling/microwave drying treatments, all of which are common preservation methods used in industry. We analyzed the particle size, surface morphology, yellowing, crystallinity, chemical groups, and hydrophilicity of the PS MPs to understand the aging process. Results show that all processing methods led to aging of PS MPs, with boiling/microwave drying having the most significant impact, followed by boiling/hot air drying, boiling/solar drying, and boiling alone. The aged PS MPs exhibited smaller size, morphological changes, reduced crystallinity, increased yellowness index and carbonyl index, higher presence of O-containing groups, and enhanced hydrophilicity. These findings provide evidence of MPs aging during thermal food processing and emphasize the potential risks associated with this pathway.

Combined effect of cold plasma-activated oxygen (CPAO) and microwave on microbial decontamination and quality of milkshake powder.

This study presents a new method combining cold plasma-activated oxygen (CPAO) and microwave (MW) to decontaminate milkshake powder, exploring its effectiveness, mechanisms, and quality impact. CPAO (6 min) alone reduced bacterial load by 0.419 log CFU/g, and MW (3 min) by 0.030 log CFU/g. However, their co-application significantly amplified decontamination, achieving a 1.265 log CFU/g reduction. CPAO-MW co-treatment inflicted more oxidative damage on bacterial cell membranes and intracellular antioxidant defense system, leading to higher mortality. It also raised protein and lipid oxidation, while decreasing vitamin C and A levels in the powder. Specifically, CPAO (6 min)-MW (3 min) co-treatment increased the carbonyl content from 0.438 to 0.891 nmol/mg protein, malondialdehyde from 0.824 to 0.996 mg/kg, and lowered vitamin C from 162.151 to 137.640 mg/kg, and vitamin A from 2.05 to 1.38 mg/kg. This study shows CPAO-MW is effective for decontaminating powdered foods but highlights a need to reduce negative effects.

Improving the texture attributes of squid meat (sthenoteuthis oualaniensis) with slight oxidative and phosphate curing treatments.

This study aimed to improve the pasty texture of squid meat by oxidative and phosphate curing (OPC) treatment, and elucidate the underlying mechanism. The shear force, springiness, weight gain, water-holding capacity (WHC), color and sensory evaluation of squid meat samples treated with a mild OPC approach (OPC_2, 10 mM H2O2 solution with complex phosphate solution) were significantly improved. However, the samples subjected to over-oxidized (20 and 30 mM H2O2 solution with complex phosphate solution) treatment did not obtain favorable outcomes. Microstructure analysis revealed that muscle fibers aggregated after moderate OPC treatments, leading to an increased spacing between muscle fiber bundles. This gap facilitated a more uniform distribution and restriction of water, according to low-field nuclear magnetic resonance (LF-NMR) results. The results from in vitro simulated oxidation of myofibrillar proteins (MPs) demonstrated that increased H2O2 led to formation of carbonyl groups and decreased sulfhydryl groups, and even secondary structure changes, according to fourier transform infrared spectroscopy (FT-IR). Particle size, zeta potential and sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) results showed that oxidation caused protein aggregation into larger molecules. This study presents a novel approach to improve pasty texture of squid meat.