Hydrolysis and oxidation of lipids in mussel Mytilus edulis during cold storage

Effects of Replacing Corn with an Aged Brown Rice-Wheat Mixture on Laying Performance, Egg Quality and Nutrient Digestibility in Laying Ducks

This study examined the effects of replacing corn with an aged brown rice (ABR)-wheat mixture (ABR: wheat = 85%:15%) on laying performance, egg quality, yolk fatty acid profile, economic benefits, serum biochemistry, and nutrient digestibility in laying ducks. A 12-week trial with six hundred 32-week-old Jinding ducks were randomly divided into five groups, with 10 replicates per group, and each replicate contained 12 ducks. The levels of ABR-wheat mixture in the diet were 0%, 12.5%, 25%, 37.5%, and 50%, respectively, to replace equal amounts of corn. The basic diet of the control group was corn-soybean meal (corn accounted for 50%). The experimental period was 12 weeks (from 32 to 43 weeks old). No significant differences were observed in laying performances (p > 0.05). From a numerical perspective, the duck-housed laying rate and egg mass were highest in the 37.5% group and lowest in the 50% group. Yolk color declined linearly (p < 0.05) over 12 weeks. The albumen height and Haugh unit showed a quadratic increase in weeks 4 and 8 (p < 0.05). The relative content of monounsaturated fatty acids (MUFA) increased linearly (p < 0.05), while the relative content of polyunsaturated fatty acids (PUFA), ω-3 PUFA, ω-6 PUFA, and ω-6/ω-3 PUFA decreased linearly in egg yolks (p < 0.05). The triglycerides (TG) content in serum showed a significant secondary change (p < 0.05), with the 50% group significantly lower than the other treatment groups (p < 0.05). The apparent digestibility of ether extract (EE) in the diets decreased linearly (p < 0.05). The apparent digestibility of crude protein (CP) in the diets was significantly reduced with the 50% group (p < 0.05), while there was no significant difference between the 0% and 37.5% groups (p > 0.05). Compared with the control group, economic analysis revealed net gains of 0.04-0.10 USD/duck at ≤37.5% substitution, but a loss (-0.04 USD) at 50%. In conclusion, the ABR-wheat mixture could reduce the yolk color and yolk PUFA content, but it could improve albumen quality and increase yolk MUFA content. High-level ABR-wheat mixture (50%) significantly reduced the TG content in serum and nutrient digestibility of the diet and also showed a numerical decrease in laying rate and egg mass. Our findings suggest that up to a 37.5% ABR-wheat mixture can effectively replace corn in laying duck diets without negatively affecting laying performance, while improving albumen quality and altering yolk fatty acid composition.

Correlation of lipid hydrolysis, oxidation, and molecular transformation with volatile compound revolution in pork during postmortem wet-aging process

Lipid hydrolysis and oxidation properties, lipid metabolites, and volatile flavors were investigated to elucidate the wet-aging process (1 h to 10 d) on lipid molecule transformation and volatile flavor evolution in pork. Phospholipase A2 (PLA2) activity increased at 12 h, with lipoxygenase (LOX) increasing from 1 h to 7 d (P < 0.05). A total of 546 differential lipids from 997 lipids and 19 aroma-active compounds out of 43 volatiles were identified, with most fatty aldehydes reaching the highest at 10 d. Acyl carnitine (18:2) and hexadecanal are potential markers to predict the wet-aging progress of pork. Correlation analysis indicated that phospholipid molecule hydrolysis by PLA2 and lipid enzymatic oxidation mediated by LOX rather than reactive oxygen species contributed to volatile aldehyde evolution, while phosphatidylcholine (16:2e/22:6) may be the key lipid molecule. These results offer insights into the lipid transformation and aroma evolution in pork during the wet-aging process.

Biomimetic Design of Underwater Adhesives Based on Tea Polyphenol-Modified Gelatin

Although many tissue adhesives with good biocompatibility are currently available, their lack of wet adhesion capacity significantly hinders their clinical application. Therefore, further development and exploration of new medical adhesives are necessary. Inspired by the adhesion mechanism of marine mussels, through modifying gelatin protein with gallic acid (GA) for wet adhesion and cross-linking gelatin (Gel) molecular chains with tea polyphenols (TP), the adhesive TP-GA/Gel was developed. The adhesive exhibited an adhesion strength of up to 130.47 kPa to porcine skin tissues and maintained a high adhesion state in various aqueous environments, demonstrating excellent and reproducible adhesion. Additionally, TP-GA/Gel possessed outstanding antimicrobial, antioxidant, and biocompatibility properties. In an in vivo wound healing study with SD rats, the wound area treated with TP-GA/Gel adhesive decreased from 10.3 mm2 to 0.9 mm2 after 15 days, promoting effective and scarless wound healing. These results highlight the promising clinical potential of TP-GA/Gel as a medical adhesive.

Lipid oxidation and lipidomic profiles of raw and thermal-extracted yak fat under hydroxyl radical-induced oxidative stress

The lipid profiles in raw fat (RF) and thermal-extracted fat (TF) from yak under hydroxyl radical-induced oxidative stress were investigated. Both hydroxyl radical and thermal extraction accelerated lipid oxidation. A total of 1168 lipids were identified and classified into 18 lipid categories. The top eight classes of lipids included PCs, PEs, TGs, SMs, CERs, PSs, FAs and PAs. Furtherly, 432 differentially abundant lipids were detected in TF samples compared to RF samples. RF and TF samples displayed a complete distinction in lipidomic profiles, and some lipids in both RF and TF samples demonstrated remarkable differences in abundance with the increasing of H2O2 concentration. RF samples demonstrated a relatively higher abundance of PCs, PEs, PSs, PGs and PIs, while TF samples exhibited a higher level of PAs, TGs, FAs and CERs. These findings indicated that radical attack and thermal extraction severely affected lipid oxidation and lipid metabolomics.

Microbial inheritance through seed: a clouded area needs to be enlightened

Seed endophytes are actively used by the mother plant as both reservoir and vector of beneficial microbes. During seed dormancy endophytes experience significant physiochemical changes and only competent endophytes could colonise successfully in seeds and some of them act as obligate endophyte that are transmitted vertically across generations. The adaptive nature of endophytes allows them to switch lifestyles depending on environment and host conditions. In this review, instead of providing broad discussion on applicability of endophytes in plant growth improvement, the fundamental nature of endophytes, their survival strategies under stress conditions, transmittance, etc. have been broadly highlighted by collaborating recent discoveries and theories. We have also tried to differentiate endophyte with their pathogenic counterpart and their survival mechanism during seed dormancy stages. Critical analyses of physio-biochemical changes in seeds during maturation and parallel modifications of life styles of seed endophytes along with pathogens will enlighten the shaded part of seed-microbiome interactions. The mutualistic interrelations as well as their shipment towards pathogenic behaviour under stress are being discussed acutely. Finally, importances of conservation of seed microbiome to maintain seed quality and vigour have been pointed out. Throughout the manuscript, the knowledge gap on seed-microbiota have been mentioned, thus, in future, studies on these areas could help us to understand properly the actual role of endophytes for the betterment of maintaining seed quality and vigour.

Effects of interactions between microorganisms and lipids on inferior volatile compound production during cold storage of grouper (Epinephelus coioides)

The interaction between microorganisms, proteins, and lipids plays a critical role in the odor production of fish. To explore the specific impact of the interaction between lipids and microorganisms on the overall odor of grouper, this study excluded the influence of proteins and assessed lipid (POV and TBARS) and microbial characteristics (biofilm mass and ATP content) in lipid solutions. The Results showed that microbial growth and lipid oxidation mutually promote each other. Lipidomics analysis identified 44 differential lipids, and microbial diversity analysis pinpointed five key microorganisms (Carnobacterium, Pseudomonas, Gluconacetobacter, Vagococcus, and Shewanella). Furthermore, 20 key volatile compounds (VOCs) related to odor changes in the grouper lipid solution were identified using HS-SPME-GC-MS. Correlation network analysis revealed potential microbial and lipid contributions to VOC categories, including alcohols, aldehydes, ketones, and nitrogen- and sulfur-containing compounds. This study provides new insights into the roles of microorganisms and lipids in flavor formation, offering valuable knowledge for improving seafood quality control.

How lipids, as important endogenous nutrient components, affect the quality of aquatic products: An overview of lipid peroxidation and the interaction with proteins

As the global population continues to grow and the pressure on livestock and poultry supply increases, the oceans have become an increasingly important source of quality food for future generations. However, nutrient-rich aquatic product is susceptible to lipid oxidation during storage and transport, reducing its nutritional value and increasing safety risks. Therefore, identifying the specific effects of lipid oxidation on aquatic products has become particularly critical. At the same time, some lipid oxidation products have been found to interact with aquatic product proteins in various ways, posing a safety risk. This paper provides an in-depth exploration of the pathways, specific effects, and hazards of lipid oxidation in aquatic products, with a particular focus on the interaction of lipid oxidation products with proteins. Additionally, it discusses the impact of non-thermal treatment techniques on lipids in aquatic products and examines the application of natural antioxidants in aquatic products. Future research endeavors should delve into the interactions between lipids and proteins in these products and their specific effects to mitigate the impact of non-thermal treatment techniques on lipids, thereby enhancing the safety of aquatic products and ensuring food safety for future generations.

Integrated lipidomics and microbiomics reveal the quality changes of fresh yak tenderloin during storage

The changes in lipid and microbial during beef storage exert a substantial impact on the overall quality of beef. In this study, lipidomics and microbiomics were used to evaluate the effects of chilled storage (at 4 °C, CS) and superchilled storage (at -2 °C, SS) on the quality of yak tenderloin. The data revealed that TG, PS, PI, PE, and Car are the key factors contributing to the generation of undesirable odor during the storage of tenderloin. Macrococcus, Lactobacillus, Myroides, and Proteobacteria directly affect the storage quality of yak tenderloin. Integrated analysis revealed that microbial metabolites interact with lipids, resulting in a deterioration of meat quality. These changes are mediated by Myroides, Pseudomonas, and Lactobacillus, which regulate fatty oxidation and metabolism of PE, PI, PS, Cer, and SM. These findings have important implications for understanding the changes in quality and microbial activity of refrigerated meat and meat products.

Exploring the correlation of microbial community diversity and succession with protein degradation and impact on the production of volatile compounds during cold storage of grouper (Epinephelus coioides)

Microorganisms, proteins, and lipids play crucial and intricate roles in the aroma generation of aquatic products. To explore the impact of the interaction between microorganisms and proteins on the volatile compounds (VOCs) in grouper, this study employed whey protein isolate (WPI) to inhibit lipid oxidation and reduce mutual interference. Changes in bacterial profiles, metabolites, and VOCs were detected. Eighteen key VOCs associated with the overall flavor of grouper were identified, and the potential relationships among microorganisms, proteins, and VOCs were explored using a correlation network. Five microorganisms (Vibrio, Vagococcus, Pseudomonas, Psychrobacter, and Shewanella) closely related to characteristic flavor compounds were identified. Additionally, 30 differential metabolites related to proteins and six metabolic pathways were screened. Therefore, this study unveils the potential interaction between microorganisms and proteins in flavor formation and provides new insights into the relationships among microorganisms, proteins, and VOCs.

Effect of ultra-high pressure heat-assisted technology combined with L-cysteine on the color of ready-to-eat shrimp during storage

This study used ultra-high pressure processing (HPP) heat-assisted technology combined with L-cysteine (L-cys) to process ready-to-eat (RTE) shrimp. Subsequently, the effects of physical field and chemical modifications on the color of RTE shrimp were studied. The results showed that the RTE shrimp treated with HPP-Heat-L-cys showed better performance in terms of brightness value (65.25) and astaxanthin (AST) content (0.71 μg/g) during storage, maintaining the original color of RTE shrimp effectively. In addition, it was observed that the application of HPP-Heat-L-cys significantly delayed phenol oxidation, lipid oxidation, and Maillard reaction compared with traditional HPP or heat treatments. Specifically, the total phenolic content of RTE shrimp treated with HPP-Heat-L-cys was higher than that of other samples, but the TBARS and browning index were lower. Furthermore, HPP-Heat-L-cys could delay the production of dark products (such as 2-methylanthraquinone, p-benzoquinone, lipofuscin and melanin), ultimately safeguarding the color stability of RTE shrimp during storage.

Assessment of the impact of whey protein hydrolysate on myofibrillar proteins in surimi during repeated freeze-thaw cycles: Quality enhancement and antifreeze potential

The quality of surimi, widely used in processed seafood, is compromised by freeze-thaw cycles, leading to protein denaturation and oxidative degradation. The objective of this study is to explore the effects of adding natural whey peptide hydrolysate (WPH) on the myofibrillar proteins of repeatedly freeze-thawed surimi. Results indicated surimi treated with 15% WPH exhibited only a 128% increase in surface hydrophobicity and a maximum peroxide value of 7.84 μg/kg, significantly lower than the control group. Additionally, salt-soluble protein content, emulsification activity, and stability decreased with the increase in freeze-thaw cycles. With a 15% WPH offering the most significant protective effect, evidenced by reductions of only 25.02%, 42.52% and 37.02% in salt-soluble protein content, emulsification activity, and stability, respectively. These outcomes demonstrate that WPH effectively reduces protein denaturation during repeated freeze-thaw processes. Future research should explore the molecular mechanisms underlying WPH's protective effects and evaluate their applicability in other food systems.

Omega 3 Blends of Sunflower and Flaxseed Oil-Modeling Chemical Quality and Sensory Acceptability

Oil blending is increasingly utilized to improve and model the characteristics of enriched oils. This study aims to investigate the effect of blending refined sunflower oil (rich in essential omega 6 fatty acids) with cold-pressed flaxseed oil (a source of essential omega 3 fatty acids) on the fatty acid composition, quality, color, and sensory characteristics of the resulting oils. Principal component analysis (PCA) showed that the optimal fatty acid composition was achieved in the sample with 20% sunflower oil and 80% flaxseed oil (20S/80F). However, developing a new product is highly complex due to the importance of oil quality and sensory characteristics. Therefore, an Artificial Neural Network (ANN) was applied to optimize the proportions of flaxseed and sunflower oil to create an oil blend with improved nutritional, oxidative, and sensory characteristics compared to the individual oils. The ANN analysis determined the optimal composition of the oil blend to be 51.5% refined sunflower oil and 48.5% cold-pressed flaxseed oil. Sensory characteristics pose a particular challenge in optimization, as flaxseed oil, which increases essential omega 3 fatty acids, has a specific taste that is not widely favored by consumers. Nonetheless, by blending with refined sunflower oil, the resulting optimal blend (51.5% refined sunflower oil and 48.5% cold-pressed flaxseed oil) possesses pleasant sensory characteristics.

Molecular mechanism of color deepening of ready-to-eat shrimp during storage

Color deepening occurs during storage of ready-to-eat (RTE) shrimps, which seriously affects their marketing cycle. This study investigated the molecular mechanisms of color deterioration in RTE shrimps during accelerated storage, shedding light on the pattern of change in colored products and content. The findings revealed significant occurrences of phenolic oxidation, lipid oxidation, and Maillard browning reactions during accelerated storage. Qualitative and quantitative analyses were conducted on the colored products resulting from these chemical reactions. Multivariate mathematical models were employed to analyze the phenolic oxidation products (2-methylanthraquinone and p-benzoquinone), lipid oxidation products (lipofuscin-like pigments and hydrophobic pyrroles), and Maillard browning products (pyrazines and melanoidins). These products were identified as the main contributors to the deepening of the color of RTE shrimps during storage. The outcomes of this research could enhance our understanding of the color change mechanism in thermally processed marine foods, providing valuable insights for quality maintenance and industrial advancement.

Changes in meat quality, metabolites and microorganisms of mutton during cold chain storage

During the cold chain storage process, changes in metabolites and microorganisms are highly likely to lead to changes in meat quality. To elucidate the changes in the composition of metabolites and microbiota during cold chain storage of mutton, this study utilized untargeted metabolome and 5R 16S rRNA sequencing analyses to investigate the changes in the longissimus dorsi under different cold chain temperatures (4 °C and -20 °C). With the extension of cold chain storage time, the meat color darkened and the content of C18:2n-6, C20:3n-6, and C23:0 were significantly increased in mutton. In this study, nine metabolites, including 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine, alanylphenylala-nine, indole-3-acrylic acid and the others, were significantly altered during cold chain storage. The abundance of the dominant microorganisms, including Brachymonas, Aeromonas, Corynebacterium and Steroidobacter, was significantly altered. Furthermore, a high correlation was observed between the different metabolites and microorganisms. These findings provide an in-depth understanding of the effects of different cold chain storage temperatures and times on the quality of mutton.

The exploration of dominant spoilage bacteria in blue mussels (Mytilus edulis) stored under different modified atmospheres by MALDI-TOF MS in combination with 16S rRNA sequencing

Few studies have addressed species-level identification of spoilage bacteria in blue mussels packed under modified atmospheres (MAs). We investigated the effect of MAs and seasons on the tentative species-level of dominant spoilage bacteria in blue mussels. Summer (s) and winter (w) blue mussels were stored at 4 °C in the atmospheres (%CO2/O2/N2): A40s (30/40/30), B60s (40/60/0), C60s (0/60/40), A40w (30/40/30), and D75w (25/75/0). In total, 122 culturable isolates were obtained at the final stage of shelf life, when mortality was high (56-100%) and total psychrotrophic bacteria counted >7 log CFU g-1. Biochemical properties were analyzed using gram reactions, catalase and oxidase activities, and salt tolerance tests. Culturable isolates were identified through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16 S rRNA gene sequence analysis. Spoilage potential tests were investigated by evaluating protease, lipase, and fermentation activities as well as gas and H2S production. The culturable isolates showed tolerance to varied salt concentrations. Psychromonas arctica, Pseudoalteromonas elyakovii, and Shewanella frigidimarina were dominating in specific MAs. Winter blue mussels resulted in a higher variation of spoilage bacteria, including S. frigidimarina, S. vesiculosa, S. polaris, Micrococcus luteus, Paeniglutamicibacter terrestris sp. nov., and Alteromonas sp.

Effect of L. Plantarum Y279 and W. Cibaria Y113 on microorganism, lipid oxidation and fatty acid metabolites in Yu jiaosuan, A Chinese tradition fermented snack

Fatty acids are one of the main sources of flavour in fermented Yu jiaosuan (YJS) in southwest China. Bacilli (50.18 %) and Oxyphotobacteria (32.70 %) were the dominant class. Lactiplantibacillus (40.51 %) and Weissella (20.43 %) were the dominant species in the inoculated fermented group (HY). The peroxide value (ZY: 0.025 g/100 g, HY: 0.016 g/100 g) and lipoxygenase (LOX) (ZY: 5.7654 U/min·g, HY: 3.3856 U/min·g) in the HY group were significantly lower compared with the natural fermentation group (ZY), while acid lipase activity (ZY: 0.3184 U/h·g, HY: 0.7075 U/h·g) and neutral lipase activity (ZY: 12.65443 U/h·g, HY: 20.25142 U/h·g) were significantly higher than the control sample. Totally 40 differential fatty acid metabolites were screened. Arachidonic acid metabolism, unsaturated fatty acid biosynthesis and linoleic acid metabolism were potential metabolic pathways. Seven major bacterial species were closely associated with 15 differential fatty acid. This study contributes to the targeted production of fatty acid functional active substances of YJS.

Changes in the Physicochemical Properties and Microbial Communities of Air-Fried Hairtail Fillets during Storage

This study assessed the physicochemical properties of air-fried hairtail fillets (190 °C, 24 min) under different storage temperatures (4, 25, and 35 °C). The findings revealed a gradual decline in sensory scores across all samples during storage, accompanied by a corresponding decrease in thiobarbituric acid reactive substances (TBARS) and total viable count over time. Lower storage temperatures exhibited an effective capacity to delay lipid oxidation and microbiological growth in air-fried hairtail fillets. Subsequently, alterations in the microbiota composition of air-fried hairtail fillets during cold storage were examined. Throughout the storage duration, Achromobacter, Escherichia-Shigella, and Pseudomonas emerged as the three dominant genera in the air-fried hairtail samples. Additionally, Pearson correlation analysis demonstrated that among the most prevalent microbial genera in air-fried hairtail samples, Achromobacter and Psychrobacter exhibited positive correlations with the L* value, a* value, and sensory scores. Conversely, they displayed negative correlations with pH, b* value, and TBARS. Notably, air-fried samples stored at 4 °C exhibited prolonged freshness compared with those stored at 25 °C and 35 °C, suggesting that 4 °C is an optimal storage temperature. This study offers valuable insights into alterations in the physicochemical properties and microbial distribution in air-fried hairtail fillets during storage, facilitating the improvement of meat quality by adjusting microbial communities in air-fried hairtail fillets.

Lipid-Induced Oxidative Modifications Decrease the Bioactivities of Collagen Hydrolysates from Fish Skin: The Underlying Mechanism Based on the Proteomic Strategy

Collagen peptides exhibit various bioactivities, including antioxidation and ACE inhibition. However, the bioactivities of collagen peptides decrease gradually due to oxidation deterioration during storage, and this degradation of bioactive peptides is rarely studied. In this study, the oxidative levels and the bioactivities of collagen peptides were investigated during an oxidative-induced storage accelerated by lipids. The results suggested that the oxidation of collagen peptides was divided into three stages. At the early stage, the carbonyl content of collagen peptides increased rapidly (from 2.32 to 3.72 μmol/g peptide), showing a close correlation with their bioactivities (for antioxidation, r = -0.947; for ACE inhibition, r = -0.911). The oxidation level in the middle stage continued but was stable, and the bioactivities decreased. At the later stage, the Schiff base and dityrosine content increased significantly and showed a strong correlation with the bioactivities (antioxidation, r = -0.820, -0.801; ACE inhibition, r = -0.779, -0.865). The amino acid and proteomic analyses showed that Met, Lys, and Arg were susceptible to oxidation and revealed their oxidative modification types. This study provided an insight into the dynamic oxidative modifications of collagen peptides, which were shown to correlate well with the change in bioactivities.

Marine Animal Co-Products-How Improving Their Use as Rich Sources of Health-Promoting Lipids Can Foster Sustainability

Marine lipids are recognized for their-health promoting features, mainly for being the primary sources of omega-3 fatty acids, and are therefore critical for human nutrition in an age when the global supply for these nutrients is experiencing an unprecedent pressure due to an ever-increasing demand. The seafood industry originates a considerable yield of co-products worldwide that, while already explored for other purposes, remain mostly undervalued as sustainable sources of healthy lipids, often being explored for low-value oil production. These co-products are especially appealing as lipid sources since, besides the well-known nutritional upside of marine animal fat, which is particularly rich in omega-3 polyunsaturated fatty acids, they also have interesting bioactive properties, which may garner them further interest, not only as food, but also for other high-end applications. Besides the added value that these co-products may represent as valuable lipid sources, there is also the obvious ecological upside of reducing seafood industry waste. In this sense, repurposing these bioresources will contribute to a more sustainable use of marine animal food, reducing the strain on already heavily depleted seafood stocks. Therefore, untapping the potential of marine animal co-products as valuable lipid sources aligns with both health and environmental goals by guaranteeing additional sources of healthy lipids and promoting more eco-conscious practices.

A comprehensive investigation on the interaction between jaceosidin, baicalein and lipoxygenase: Multi-spectroscopic analysis and computational study

Lipoxygenase (LOX) has the harmful effect of accelerating lipid oxidation, and polyphenols have the inhibitory effect on lipoxygenase. However, there were rare researches investigated on the interactions between polyphenols and LOX. In this study, the binding mechanisms between polyphenols (Jaceosidin-JSD and baicalein-BCL) and LOX were investigated by multi-spectroscopic analysis and computational study. Both JSD and BCL binding to LOX resulted in static fluorescence quenching, and the complexes of JSD-LOX and BCL-LOX were built at a molar ratio of 1:1, respectively. The binding constants of LOX-JSD (72.18 × 105 L/mol at 298 K) and LOX-BCL (12.43 × 105 L/mol at 298 K) indicated that LOX had stronger binding affinity to JSD compared to BCL. Compared with BCL-LOX, the JSD-LOX system formed more hydrogen bonds which ensured a stronger bond between JSD and LOX. The studies in molecular dynamics also demonstrated that the JSD-LOX complex is more stable, and the addition of JSD is more conducive to the complex formation. The current study provides some new insights for the study on the inhibition of lipid oxidation and affords a new strategy for the discovery of novel food preservatives.

Effects of food processing on the lipid nutritional quality of commercially important fish and shellfish

Fish and shellfish are important sources of high quality lipids, especially omega-3 long-chain polyunsaturated fatty acids. In most countries, seafood is eaten cooked to eliminate any potential parasites and pathogens. In addition, cold storage plays an important role in extending the shelf life of seafood. However, both cooking and storage processes can cause alterations in the lipid content and fatty acid profile of fish and shellfish. Although the lipid nutritional quality of fish and shellfish have recently been reviewed, these reviews mainly focus on raw seafood, and information on the impact of food processing on the lipid nutritional quality of fish and shellfish still lacks coherence. Therefore, this study was carried out to provides a critical reviews on the effects of food processing, especially cooking and cold storge, on the lipid nutritional quality of fish and shellfish. Overall, from the perspective of lipid nutritional quality, baking and steaming are the most recommended cooking methods for fish and shellfish, respectively, while it is strongly not recommended to fry seafood with margarine. For cold storage, 3 days and 2 weeks are the most recommended storage periods for refrigeration and frozen storage, respectively. This article can provides consumers with useful information to choose food preparation and storage methods based on their personal interest in specific lipid nutritional quality indicators.

Exploring the effects of lipid oxidation and free fatty acids on the development of volatile compounds in grouper during cold storage based on multivariate analysis

To investigate the relationship between lipid oxidation and the development of volatile compounds (VOCs) in grouper lipid during cold storage, lipids were extracted from grouper as a single-factor study to avoid the complex interactions between microorganisms and proteins. Lipid oxidation during storage and the content of 12 long-chain fatty acids (FAs) in grouper lipids were evaluated. The HS-SPME-GC-MS technique was used to analyze the VOCs in grouper lipids, and a total of 13 key VOCs, primarily comprising alcohols and aldehydes, were screened. Pearson correlation analysis showed a strong acorrelation between these 13 key VOCs, which influenced the overall flavor of grouper lipids, and lipid oxidation, mainly involving secondary oxidation of lipids and the oxidation of long-chain polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Possible solutions for grouper lipid deterioration were proposed, providing a reference for maintaining the overall quality of grouper and regulating flavor formation.

The Sous Vide Cooking of Mediterranean Mussel (Mytilus galloprovincialis): Safety and Quality Assessment

This study involves an investigation of the effects of various cooking temperatures, freeze-thaw processes, and food preservatives on the quality and shelf-life of sous vide Mediterranean mussels. Cooking temperatures of 80 °C or above significantly improved the microbiological quality, with bacterial counts remaining within the acceptability range for human consumption even after 21 days of refrigerated storage. Fast freezing followed by slow thawing preserved the highest moisture content, potentially improving texture. Sensory analysis revealed that refrigerated sous vide mussels maintained a comparable taste to freshly cooked samples. Frozen samples reheated via microwaving exhibited more intense flavour than pan-reheated or fresh mussels. Food additives, including citric acid, potassium benzoate, and potassium sorbate, alone or in combination with grape seed oil, significantly reduced total volatile basic nitrogen and thiobarbituric acid-reactive substances during 28 days of storage, indicating decreased spoilage and lipid oxidation. Mussels with a combination of these additives registered a nitrogen content as low as 22 mg of N/100g after 28 days, well below the limit of acceptability (<35 mg of N/100g). Food additives also inhibited bacterial growth, with mesophilic bacteria count below 3.35 Log CFU/g after 28 days, compared with 5.37 Log CFU/g in control samples. This study provides valuable insights for developing optimal cooking and preservation methods for sous vide cooked seafood, underscoring the need for further research on optimal cooking and freeze-thaw protocols for various seafood types.

Enrichment of antiplatelet peptides and removal of fishy odor from silver carp skin collagen hydrolysates by macroporous resins: pH value of loading sample affects the peptides separation

Enrichment of antiplatelet peptides from silver carp skin collagen hydrolysates (CH) was studied using macroporous resins. Static adsorption showed that XAD-16 resin was the suitable resin due to its high adsorption capacity. The dynamic desorption of CH was studied on XAD-16 resin by ethanol gradient elution. Interestingly, pH value of loading sample had a great impact on the peptides separation. Results revealed that the yield and the antiplatelet activity of Ethl-20% fraction were highest at loading sample pH 6.0. The antiplatelet peptides were enriched in the 20% ethanol fraction with IC₅₀ 2.03 mg/mL compared to IC₅₀ of CH, 4.7 mg/mL. Besides, the Ethl-20% fraction had a weakest fishy odor. Moreover, a series of peptides containing Hyp-Gly or Pro-Gly were identified from Ethl-20% fraction, which contributed to the antiplatelet activities. This study provided a simple and efficient method for large-scale separation enrichment of antiplatelet peptides as functional foods from CH.

Effects of ethanol pretreatment on osteogenic activity and off-flavors in blue mussel (Mytilus edulis L.) enzymatic hydrolysates

Aquatic protein hydrolysates have many biological activities, but the off-flavor seriously decreases their commercial acceptability. Therefore, it is important to invest in finding an effective deodorization of aquatic hydrolysates that do not affect activities. In this study, ethanol pretreatment of mussel was applied to establish a new method to deodorize the blue mussel (Mytilus edulis L.) hydrolysates. LC-MS and GC-MS analysis results showed that 87.34% of fatty acids, 83.94% of aldehydes, most volatile flavor compounds including aldehydes, ketones, alcohols, acids, and hydrocarbons were decreased after ethanol pretreatment. Besides, it was found that the enzymatic hydrolysates of mussel with or without ethanol pretreatment showed high osteogenic activity, which induced an increase of 33.65 ± 4.36% and 31.77 ± 5.45% in MC3T3-E1 cell growth. These results suggest that ethanol pretreatment has beneficial potential for improving the flavor aspects of blue mussel peptides which may have the potential to stimulate bone regeneration and formation.

Effect of Vacuum Impregnation and High Hydrostatic Pressure Treatments on Shelf Life, Physicochemical, and Sensory Properties of Seabream Fillets

Marination is commonly used to preserve fish, which, in combination with other non-thermal technologies, such as vacuum impregnation and high hydrostatic pressure, may help to preserve freshness and extend shelf life. In addition, marination may mask changes in physicochemical properties and the sensory attributes of fish resulting from intense pressurization treatments. In this study, we evaluated the effects of vacuum impregnation (50 mbar for 5 min) alone or in combination with a moderate pressurization treatment (250 MPa for 6 min) on the physicochemical properties, microbiological and oxidative stability, and sensory properties of refrigerated seabream fillets. Compared to conventional marination, vacuum impregnation alone had no effect on the aforementioned properties, except for a higher perception of lemon aroma (0.9 vs. 1.6). However, vacuum impregnation with pressurization reduced the total viable mesophilic aerobic bacteria to counts below 4 log colony forming units (CFU)/g after 16 days of storage at ≤ 2 °C, compared to 6 log CFU/g with conventional marination. Additionally, the color and texture were affected by the pressurization treatment. However, color was more susceptible, and at the beginning of storage, lightness was higher in the pressurized samples than in the control (52 vs. 78). Regardless, this whitening effect and other minor changes in texture and sensory properties compared to conventional marination with vacuum impregnation with pressurization can be considered of little relevance considering the increase in shelf life, the lack of lipid oxidation (maintained at low and similar levels as those of the non-pressurized samples), and the intrinsic whitening effects of certain marinades.

Determination of free fatty acids in Antarctic krill meals based on matrix solid phase dispersion

Amino-modified mesoporous silicawas prepared by modifying mesoporous silica with 3-aminopropyltriethoxysilane and used as adsorbents in matrix solid-phase dispersion (MSPD) to analyze free fatty acids (FFAs) in krill meals for the first time. The adsorption-desorption experiments and Fourier-transform infrared spectroscopy showed amino-modified mesoporous silica with ordered mesoporous structure was successfully synthesized. The adsorption experiments including static and dynamic adsorption showed thatabsorption capacity of amino-modified mesoporous silica towards FFAs was better than that of aminated silicon microspheres at all concentrations. Under optimal extraction conditions, outstanding linearity (0.1-12000 nmol g^-1), low LODs (0.05-1.25 nmol g^-1), satisfactory recoveries (82.17-96.43%) and precisions (0.19-5.26%) were obtained. Moreover, the application of MSPD for FFAs analysis avoided complicated lipid extraction procedures and accomplished the homogenization, crushing, extraction and cleaning of the samples in one step. Consequently, this approach provides an alternative choice to the existing approach for analyzing FFAs in solid and semi-solid samples.

LC/MS analysis of storage-induced plasmalogen loss in ready-to-eat fish

Plasmalogens are functional and oxidation-sensitive phospholipids abundant in fish. Chilling and freezing are common storage methods for maintaining the quality of fish, but their effect on plasmalogen preservation has not been studied. Therefore, plasmalogen loss in ready-to-eat tuna meat during storage under different conditions was investigated. LC/MS was used to analyze the time- and temperature-dependent changes of plasmalogens, which was the most evident for the species with an ethanolamine headgroup and polyunsaturated fatty acyl chains. Moreover, a series of oxidized plasmalogen molecules were identified, and their storage-induced accumulation was observed. Plasmalogen loss was strongly correlated with total lipid oxidation and phospholipid degradation. Repeated freeze-thaw cycles were found to accelerate the loss of plasmalogens, whereas the different thawing methods did not. The present study provides a deeper understanding of changes in lipid nutrients from fish meat during storage and demonstrates the importance of using advanced strategies to maintain food quality.

Proteomics and Metabolomics Profiling of Pork Exudate Reveals Meat Spoilage during Storage

Previous studies have evaluated pork quality by omics methods. However, proteomics coupled with metabolomics to investigate pork freshness by using pork exudates has not been reported. This study determined the changes in the profiles of peptides and metabolites in exudates from pork stored at different temperatures (25, 10, 4, and −2 °C). Multivariate statistical analysis revealed similar changes in profiles in exudates collected from pork stored at −2 and 4 °C, and additional changes following storage at higher temperatures. We identified peptides from 7 proteins and 30 metabolites differing in abundance between fresh and spoiled pork. Significant correlations between pork quality and most of the peptides from these 7 proteins and 30 metabolites were found. The present study provides insight into changes in the peptide and metabolite profiles of exudates from pork during storage at different temperatures, and our analysis suggests that such changes can be used as markers of pork spoilage.

Effects of curcumin-mediated photodynamic treatment on lipid degradation of oysters during refrigerated storage

BACKGROUND

Oyster's lipid degradation leads to a decrease in edible and nutritional value. Curcumin-mediated photodynamic treatment (PDT) is an innovative non-thermal technology, although evaluation of the oyster's lipid degradation has been scarce. In the present study, we investigated peroxide value, thiobarbituric acid reactive substance, triacylglycerol and free fatty acids to evaluate the effect of curcumin-mediated PDT on lipid degradation of oysters during refrigerated storage.

RESULTS

The results showed that curcumin-mediated PDT could delay oyster's lipid degradation. Next, the activities of enzymes were detected to determine the mechanisms behind the effects of curcumin-mediated PDT. It was revealed that the activities of lipase, phospholipase A₂ (PLA₂ ), phospholipase C (PLC), phospholipase D (PLD) and lipoxygenase (LOX) were significantly inhibited after curcumin-mediated PDT (P < 0.05). Furthermore, 16 s rRNA analysis established that the relative abundances of Pseudoalteromonas and Psychrilyobacter were reduced by 51.58% and 43.82%, respectively, after curcumin-mediated PDT.

CONCLUSION

Curcumin-mediated PDT could delay oyster's lipid degradation by inhibiting the activities of lipase, PLA₂ , PLC, PLD and LOX, as well as by changing the oyster's microbial composition, reducing the relative abundance of Pseudoalteromonas and Psychrilyobacter. © 2021 Society of Chemical Industry.

Investigation of the changes in lipid profiles induced by hydroxyl radicals in whiteleg shrimp (Litopenaeus vannamei) muscle using LC/MS-based lipidomics analysis

The oxidative effects of hydroxyl radical on the alterations of lipid profiles were investigated in shrimp muscle. Chemical results indicate peroxide value (PV) and thiobarbituric acid index (TBA-i) value in oxidation-treated shrimp significantly increased with oxidation time, and hydroxyl radical concentration increased, compared with those of in fresh samples. It was assumed that radical attack might induce lipid decomposition, backbone cleavage, and/or side-chain modifications. LC/MS-based lipidomics analysis revealed 835 lipids in shrimp assigned to 27 lipid classes, including 219 PCs and 98 CLs. In total, 86 and 34 differentially abundant lipids (DALs) accumulated at lower and higher levels, respectively, were identified in OS, compared with that in FS. This indicates hydroxyl radical attack altered the lipidomics profiles of shrimp muscle to a large extent. Furthermore, DALs, including CL 62:2, PC 38:3, and PE 34:9, could be considered as promising biomarkers to distinguish fresh and oxidation-treated shrimp products.

Significantly Different Lipid Profile Analysis of Litopenaeus vannamei under Low-Temperature Storage by UPLC-Q-Exactive Orbitrap/MS

Low-temperature storage is one of the most important preservation methods for aquatic product storage. However, the effects of low-temperature storage on the lipid profiles of shrimp are unclear. Herein, UPLC-Q-Exactive Orbitrap/MS combined with LipidSearch software was applied to analyze the effect of three low storage temperatures (4 °C, -2 °C, and -18 °C) on the lipidomics of Litopenaeus vannamei. A total of 15 lipid classes were analyzed, and PC, PE, DG, and TG accounted for vast majority of peak areas. Furthermore, 531 individual lipid variables enriched in 12 metabolic pathways were identified via bioinformatics analysis methods. A total of 56 significantly different lipid molecular species (55 belonging to PC, PE, DG, and TG) were selected as potential biomarkers of lipid oxidation via correlational analysis between physical properties (texture and color) and individual lipid variables. The results indicated that the three low storage temperatures caused different effects on the lipidomics profile of L. vannamei, and PC, PE, DG, and TG could become potential focuses in further studies of lipid oxidation in L. vannamei.

Tea polyphenols increase the antioxidant status of laying hens fed diets with different levels of ageing corn

This study was conducted to evaluate the effects of ageing corn levels (stored for 4 years) with or without the supplementation of tea polyphenols (TPP) on the performance, egg quality and antioxidant status of laying hens. A total of 288 Lohmann commercial laying hens (63-week-old) were used under a 2 × 4 factorial arrangement with 4 levels of dietary ageing corn (0%, 25%, 50%, or 100%) and 2 levels of TPP (0 and 600 mg/kg) for 8 wk. Dietary ageing corn linearly decreased (P < 0.05) the egg production, serum total antioxidant capacity (T-AOC), liver glutathione peroxidase (GSH-Px) of laying hens, yolk index, yolk colour, 1,1-diphenyl-2-picrylhydrazyl (DPPH) value and the reducing power value of egg yolk, but it linearly increased (P < 0.05) the feed conversion rate, ovary malondialdehyde (MDA) content of laying hens, and the protein carbonyl content of egg yolk. Tea polyphenol supplementation increased (P < 0.05) the serum T-AOC, serum superoxide dismutase (SOD), liver SOD, liver GSH-Px, ovary SOD, GSH-Px, the expression of antioxidant-related genes of laying hens, albumen height, Haugh unit, DPPH value and the majority free amino acids of egg yolk, but it decreased (P < 0.05) the serum MDA content of laying hens, MDA and protein carbonyl of egg yolk. In conclusion, the ageing corn significantly reduced the performance, egg quality, antioxidant status and egg antioxidant capacity of laying hens, while TPP supplementation partially counteracted the adverse effects, especially antioxidant status and egg antioxidant capacity of laying hens.

Shelf-Life of Half-Shell Mussel (Mytilus edulis) as Affected by Pullulan, Acidic Electrolyzed Water, and Stable Chlorine Dioxide Combined Ice-Glazing during Frozen Storage

Mussel (Mytilus edulis) is an economic shellfish with a high nutritional value. Due to the high amount of protein and fat, fresh mussels are susceptible to spoilage during storage. In the present study, how a combination of pullulan, acidic electrolyzed water (AEW), and stable chlorine dioxide (ClO₂) ice-glazing treatments affect the quality of mussels was investigated during 90 days of frozen storage. The results indicate that the combined glazing treatment effectively maintained the mussel muscle quality during storage mainly due to its air barrier actions. Mussel samples coated with AEW and ClO₂ showed lower aerobic plate counts than other groups, resulting from the strong antibacterial action of AEW and ClO₂. After 90 days of frozen storage, the mussel glazed with a combination of AEW, ClO₂, and pullulan solutions showed better texture properties, higher content of myofibrillar proteins, higher Ca²⁺-ATPase activity, and more SH groups than the other glazing treatments. The water-holding capacity and SEM observations showed that the pullulan glazing efficiently inhibited the physical damage caused by the frozen and long-term storage, which mainly contributed to the high amount of hydrophilic hydroxyl groups in the muscle tissues. The present study supports the use of a combination of cryoprotectants for extending the shelf-life of frozen mussel products during long-term storage.

The relationship between flavor formation, lipid metabolism, and microorganisms in fermented fish products

Traditional fermented fish products are favored due to their unique flavors. The fermentation process of fish is accompanied by the formation of flavor substances through a complex metabolic reaction of microorganisms, especially lipolysis and lipid oxidation. However, it is difficult to precisely control the reaction of microorganisms during the fermentation process in modern industrial production, and fermented fish products have lost their traditional characteristic flavors. The purpose of this review is to summarize the different kinds of fermented fish, core microorganisms in it, and flavor formation mechanisms, providing guidance for industrial cultural starters. Future research on the flavor formation mechanism is necessary to confirm the relationship between flavor formation, lipid metabolism, and microorganisms to ensure stable flavor and safety, and to elucidate the mechanism directly toward industrial application.

Effects of acid and alkaline treatments on physicochemical and rheological properties of tilapia surimi prepared by pH shift method during cold storage

Microbial, physicochemical, rheological, and microstructural changes of surimi prepared by pH shift methods and the traditional water-washing method during cold storage were investigated. The starting aerobic mesophilic count (AMC) of pH shift surimi was around 1 log CFU/g lower than water-washed surimi, suggesting antimicrobial effects of the pH shift. All samples could be stored for 5 to 6 days based on the AMC results. Throughout the storage, the gel strength of alkaline-treated surimi increased from 204.2 to 491.9 g, while water-washed surimi decreased from 462.1 to 172.9 g. After the storage, alkaline-treated surimi showed lower total volatile basic nitrogen (TVB-N) value and smaller network hole size that was suitable for incorporation of moisture and starch. It also remained its rheological properties comparing with acid-treated surimi, with better odour properties, less protein degradation, and better network formation. The results indicate that alkaline-treated surimi is more suitable for cold storage.

Differences in lipid composition of Bigeye tuna (Thunnus obesus) during storage at 0 °C and 4 °C

This study aimed to investigate the lipid oxidation and distribution in Bigeye tuna stored at 0 °C and 4 °C for 6 days. Tuna were evaluated by determining the peroxide value (POV), acid value (AV), anisidine value (AnV), polyene index, fluorescence ratio (FR), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) content, and major glycerophospholipid molecular species. The value of lipid oxidation indexes (POV, AV, AnV, FR, PC, PE and PI) increased as the storage time increased. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) results indicated that the major types of lipids included diacylglycerol (DAG), monoacylglycerol (MAG), phospholipid (PL), and triacylglycerol (TAG). At least 136 PC and 64 PE molecular species were identified in Bigeye tuna. The results of the confocal laser scanning microscope analysis indicated the distribution of TAG and PL particles. In addition, principal component analysis showed that the contents of PI and TAG were positively correlated with PC, polyene index and lipid content but negatively correlated with PI, POV, FR, AOV, AnV, MAG, and DAG, which might be explained by distinguishing the lipid parameters affecting lipid oxidation. Therefore, this study may provide a novel method to evaluate lipid changes and contribute to the balanced nutritional value of aquatic foods during cold storage.

The impact of prolonged frozen storage on the preparation quality of bird skins and skeletons in zoological collections

Specimens from zoological collections play a pivotal role in improving scientific knowledge in many natural science disciplines. To guarantee an optimum state of conservation and ensure their usefulness, the preparation process employed is crucial. Skins and skeletons are key elements in vertebrate scientific collections and, ideally, are prepared from recently deceased animals; however, specimens are often stored in a frozen state for a long time (years) prior to preparation. Whether the duration of this frozen state has a deleterious effect on preparation quality has rarely been studied. The main objective of this study was thus to contribute towards research into zoological preparation by testing to see whether prolonged frozen storage hinders the preparation of bird skins and skeletons. We used the common buzzard (Buteo buteo) and the barn owl (Tyto alba) as biological models. Our results showed that long-term frozen storage led to weight loss, bone marrow acidification and solidification, and hampered skin preparation. The necropsy affected weight loss and decreased the skin tear resistance, probably due to tissue dehydration. Thus, prolonged frozen storage appears to have a harmful effect on the preparation quality of vertebrate specimens. Since frozen storage could ultimately have an impact on the conservation and scientific use of museum specimens, practices should be implemented to minimise the amount of time specimens are frozen or to mitigate any detrimental effects. More importance should be attached to research on zoological preparation since it is fundamental for optimising the quality, conservation status, and value of museum collections.

Molecular mechanism of lipid transformation in cold chain storage of Tan sheep

Cold chain (-20 °C) is one of the main transportation methods for storage of Tan sheep products. Lipids (66) in seven subclasses involved in sphingolipid, glycerophospholipid and fatty acid degradation metabolism were quantified in Tan sheep under cold chain storage, including fatty acyl carnitines, phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE), ceramides, sphingomyelin (SM) and lysophosphatidylethanolamine (LPE). Lipid transformation and molecular mechanism analyzed using fragmentation mechanisms and UHPLC-Q-Orbitrap MS/MS combined with lipidomics approaches determined transient increases of certain PC, PE and fatty acyl carnitine during the first 12 days of cold storage, subsequent declines of SM, PC, PE and fatty acyl carnitine, as well as increases of ceramide, LPC and LPE (24 days). These results offered insights into lipid transformation and quality of Tan sheep during cold chain storage.

Change of lipids in whelks (Neptunea arthritica cumingi Crosse and Neverita didyma) during cold storage

The objective of this study was to evaluate the change of lipids in two whelk samples during cold storage. Results showed that the peroxide value (PV) and thiobarbituric acid reactive substance (TBARS) increased while the percentage of polyunsaturated fatty acid decreased, indicating that lipid oxidation occurred. The cold storage significantly reduced the levels of triacylglycerol (TAG), polar lipid (PoL), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) but increased the levels of acid value (AV), free fatty acid (FFA) and monoacylglycerol, suggesting the hydrolysis of lipids. Moreover, the results showed that the lipoxygenase, acid lipase and phospholipase contributed to the hydrolysis and oxidation of lipids in the two whelks. Additionally, partial least squares discriminant analysis showed PC was positively correlated with PE, PoL and TAG, but negatively correlated with AV, FFA, PV and TBARS, indicating there is a close relationship between hydrolysis and oxidation of lipids.