Lipid Oxidation Research Articles

Obesity-induced tissue alterations resist weight loss: A mechanistic review.

Interventions aimed at weight control often have limited effectiveness in combating obesity. This review explores how obesity-induced dysfunction in white (WAT) and brown adipose tissue (BAT), skeletal muscle, and the brain blunt weight loss, leading to retention of stored fat. In obesity, increased adrenergic stimulation and inflammation downregulate β-adrenoreceptors and impair catecholaminergic signalling in adipocytes. This disrupts adrenergic-mediated lipolysis, diminishing lipid oxidation in both white and brown adipocytes, lowering thermogenesis and blunting fat loss. Emerging evidence suggests that WAT fibrosis is associated with worse weight loss outcomes; indeed, limiting collagen and laminin-α4 deposition mitigates WAT accumulation, enhances browning, and protects against high-fat-diet-induced obesity. Obesity compromises mitochondrial oxidative capacity and lipid oxidation in skeletal muscle, impairing its ability to switch between glucose and lipid metabolism in response to varying nutrient levels and exercise. This dysfunctional phenotype in muscle is exacerbated in the presence of obesity-associated sarcopenia. Additionally, obesity suppresses sarcolipin-induced sarcoplasmic reticulum calcium ATPase (SERCA) activation, resulting in reduced oxidative capacity, diminished energy expenditure, and increased adiposity. In the hypothalamus, obesity and overnutrition impair insulin and leptin signalling. This blunts central satiety signals, favouring a shift in energy balance toward energy conservation and body fat retention. Moreover, both obese animals and humans demonstrate impaired dopaminergic signalling and diminished responses to nutrient intake in the striatum, which tend to persist after weight loss. This may result in enduring inclinations toward overeating and a sedentary lifestyle. Collectively, the tissue adaptations described pose significant challenges to effectively achieving and sustaining weight loss in obesity.

Adsorption study on the formation of interfacial layers based on birch glucuronoxylans

Glucuronoxylans (GX), particularly crude fractions obtained by pressurized hot water extraction of birch wood, act as potent emulsifiers and stabilizers against physical separation and lipid oxidation. Herein, we studied the adsorption of GX on hydrophobic interfaces to correlate their multicomponent character towards the formation of interfacial layers in emulsions. Dynamic interfacial tension (DIFT) and quartz crystal microgravimetry with dissipation monitoring (QCM-D) were applied to various GX fractions and the results compared with those from cellulose-based emulsifiers. The roles of residual lignin and polysaccharides are discussed considering the formation of interfacial layers during emulsification. The DIFT of the different GXs reached quasi-equilibrium faster as the lignin concentration increased, implying a correlation between the rate of adsorption and the residual lignin content. The effect of NaCl addition was more pronounced in polysaccharide-rich fractions, indicating that the polysaccharide fraction modulated the effect of ionic strength. QCM-D showed that despite the fast adsorption exhibited by the lignin-rich GX extract in the DIFT curves, the adsorbed materials were lightweight, suggesting that the polysaccharide fraction built the bulk of the interfacial layer. These results provide a foundation towards understanding the role of GX in interfacial stabilization beyond traditional plant-based counterparts.

Soybean molasses increases subcutaneous fat deposition while reducing lipid oxidation in the meat of castrated lambs.

This study aimed to evaluate the effect of including soybean molasses (SM) on performance, blood parameters, carcass traits, meat quality, fatty acid and muscle (longissimus thoracis) transcriptomic profiles of castrated lambs. Twenty Dorper × Santa Inês lambs (20.06 ± 0.76kg BW) were assigned to a randomized block design, stratified by BW, with the following treatments: CON - 0g/kg of SM and SM20 - 200g/kg of SM on DM basis, allocated in individual pens. The diet consisted of 840g/kg concentrate and 160g/kg corn silage for 76 days, with the first 12 days as an adaptation period and the remaining 64 days on the finishing diet. The SM20 diet increased blood urea concentration (P = 0.03) while reduced glucose concentration (P = 0.04). Lambs fed SM showed higher subcutaneous fat deposition (P = 0.04) and higher subcutaneous adipocyte diameter (P < 0.01), in addition to reduced meat lipid oxidation (P < 0.01). Soybean molasses reduced the quantity of branched-chain fatty acids in longissimus thoracis (P = 0.05) and increased the quantity of saturated fatty acids (P = 0.01). In the transcriptomic analysis, 294 genes were identified as differentially expressed, which belong to pathways such as oxidative phosphorylation, citric acid cycle, and monosaccharide metabolic process. In conclusion, diet with SM increased carcass fat deposition, reduced lipid oxidation, and changed the energy metabolism, supporting its use in ruminant nutrition.

Magnolol ameliorates fumonisin B1-induced oxidative damage and lipid metabolism dysfunction in astrocyte-like C6 cells

The neurotoxicity of fumonisin B1 (FB1), a commonly detected mycotoxin in crops and the environment, has attracted considerable attention in recent years. However, no effective method for eliminating FB1 completely exists due to the thermal stability and water solubility of this mycotoxin. Magnolol (MAG) is a neolignane with antioxidative and neuroprotective effects. It has been applied in neurotoxicity treatment. However, the application of MAG to attenuate FB1-induced toxicity has not been reported. This study explored the protective mechanism of MAG against FB1-induced damage in C6 cells through antioxidant and lipid metabolism modulation. Results showed that exposure to 15 μM FB1 caused oxidative stress by changing the levels of malondialdehyde, reactive oxygen species, total superoxide dismutase, catalase, and total glutathione. These changes were reversed by MAG addition, especially at the concentration of 80 μM. The protective effects of MAG were further confirmed by the reduction in the phosphorylation levels of proteins in the MAPK signaling pathway. Lipidomics analysis identified 263 lipids, which belong to 24 lipid classes. Among all of the identified lipids, triglycerides (TGs), diglycerides (DGs), phosphatidylcholines (PCs), wax monoesters (WEs), Cers, and phosphatidylethanolamines (PEs) were major categories. Moreover, nine categories of lipids showed the opposite change trend in the FB1 exposure and MAG 80 groups. A further investigation of the 34 co-occurring differential lipids with remarkable changes (P value < 0.05 and VIP value > 1) in the control, FB1 exposure, and MAG 80 groups was performed. Therein, nine lipids (PCs, LPCs, and SM) were screened out as potential biomarkers to reveal the cytoprotective effects of MAG. This work is the first to investigate the rescue mechanism of MAG in FB1-induced cytotoxicity. The obtained results may expand the application of MAG to alleviate the toxicity of mycotoxins.

Difference comparison of characteristic aroma compounds between braised pork cooked by traditional open-fire and induction cooker and the potential formation cause under electromagnetic cooking

The characteristic aroma compounds of braised pork were identified through molecular sensory science and PLSR analysis, and the difference between two cooking methods, traditional open-fire (BPF) and induction cooker (BPC), was compared. Seventeen aroma compounds with odor activity values (OAVs) > 1 were identified in both samples. BPF revealed higher OAVs for most of the aroma compounds compared to BPC, and the higher aroma quality. Aroma recombination and omission experiments confirmed that twelve aroma compounds significantly contributed to the characteristic aroma of braised pork, and eight compounds such as hexanal, (E)-2-octenal, and methanethiol were further confirmed as important contributors by PLSR analysis. Furthermore, PLSR analysis clarified the role of aldehydes such as hexanal, (E)-2-octenal, and (E,E)-2,4-decadienal in contributing to fatty attribute, whereas methanethiol was responsible for the meaty aroma. These characteristic aroma compounds mainly derived from lean meat due to its high content of phospholipids, and the exogenous seasonings contributed to the balanced characteristic aroma profile of braised pork by altering the distribution of these characteristic aroma compounds. Variations in heating parameters affected the formation of lipid oxidation and Strecker degradation products, which might explain aroma discrepancy between braised pork cooked by two methods with different heat transfer efficiencies.

Effect of different cooking conditions on the quality characteristics of chicken claws

AbstractChicken claw products with their unique texture are loved by consumers, and cooking is a key step to affect the taste of chicken claw consumption, through the moderate hydrolysis of proteins and a series of physicochemical changes, so that the chicken claw gets tender and presents a crispy taste, but the current research on the optimal cooking conditions for chicken claw is still relatively small. In the present work, combinations of time (11, 13, 15, 17, and 19 min) and temperature (82, 86, 90, 94, and 98°C) were applied to the cooking of chicken claws. The effects of different cooking conditions on the quality characteristics of chicken claws were investigated, with special emphasis on the cooking loss rate, color, texture properties, lipid oxidation, myofibrillar fragmentation index (MFI), and total sulfhydryl content. The results showed that the cooking loss rate, lipid oxidation, and MFI value of chicken claws gradually increased, and the total color difference (∆E), puncture force, shear force, and total sulfhydryl content gradually decreased with the increase of cooking temperature and cooking time. Overall, chicken claws cooked at 86, 90, and 94°C for 15 and 17 min had better texture and flavor.

Melatonin Mitigates Lead-Induced Oxidative Stress and Modifies Phospholipid Profile in Tobacco BY-2 Suspension Cells.

Many studies have shown that melatonin (an indoleamine) is an important molecule in plant physiology. It is known that this indoleamine is crucial during plant stress responses, especially by counteracting secondary oxidative stress (efficient direct and indirect antioxidant) and switching on different defense plant strategies. In this report, we present exogenous melatonin's potential to protect lipid profile modification and membrane integrity in Nicotiana tabacum L. line Bright Yellow 2 (BY-2) cell culture exposed to lead. There are some reports of the positive effect of melatonin on animal cell membranes; ours is the first to report changes in the lipid profile in plant cells. The experiments were performed in the following variants: LS: cells cultured on unmodified LS medium-control; (ii) MEL: BY-2 cells cultured on LS medium with melatonin added from the beginning of culture; (iii) Pb: BY-2 cells cultured on LS medium with Pb2+ added on the 4th day of culture; (iv) MEL+Pb: BY-2 cells cultured on LS medium with melatonin added from the start of culture and stressed with Pb2+ added on the 4th day of culture. Lipidomic analysis of BY-2 cells revealed the presence of 40 different phospholipids. Exposing cells to lead led to the overproduction of ROS, altered fatty acid composition and increased PLD activity and subsequently elevated the level of phosphatidic acid at the cost of dropping the phosphatidylcholine. In the presence of lead, double-bond index elevation, mainly by higher quantities of linoleic (C18:2) and linolenic (C18:3) acids in the log phase of growth, was observed. In contrast, cells exposed to heavy metal but primed with melatonin showed more similarities with the control. Surprisingly, the overproduction of ROS caused of lipid peroxidation only in the stationary phase of growth, although considerable changes in lipid profiles were observed in the log phase of growth-just 4 h after lead administration. Our results indicate that the pretreatment of BY-2 with exogenous melatonin protected tobacco cells against membrane dysfunctions caused by oxidative stress (lipid oxidation), but also findings on a molecular level suggest the possible role of this indoleamine in the safeguarding of the membrane lipid composition that limited lead-provoked cell death. The presented research indicates a new mechanism of the defense strategy of plant cells generated by melatonin.

The potential formation mechanism of key volatile compounds in pumpkin seeds performed with different heat processing methods based on Maillard reaction and lipid oxidation

The potential formation mechanism of key volatile compounds in pumpkin seeds performed with different heat processing methods based on Maillard reaction and lipid oxidation

Modulation of the Nrf-2 and HO-1 signalling axis is associated with Betaine's abatement of fluoride-induced hepatorenal toxicities in rats.

Sodium fluoride (NaF) ingestion has several detrimental effects in humans and rodents. NaF mechanisms of toxicity include perturbation of intracellular redox homeostasis and apoptosis. Betaine (BET) is a modified amino acid with anti-inflammatory, antioxidant, and anti-apoptotic properties. This study investigates BET's effect on NaF-induced hepatorenal toxicities in rats. Experimental rats (n=30) were randomly assigned to groups (n=6) and treated by gavage for 28 days. Group I (2 mL of distilled water), Group II (NaF: 9 mg/kg) alone, Group III: (BET: 100 mg/kg), Group IV: (NaF: 9 mg/kg and BET 1: 50 mg/kg), and Group V: (NaF: 9 mg/kg and BET 2: 100 mg/kg). Our findings revealed significantly (p<0.05) increased hepatic transaminase activities alongside creatinine and urea levels following NaF-alone treatment in addition to increased oxidative status, lipid peroxidation, reactive oxygen and nitrogen species, decreased superoxide dismutase, catalase, glutathione-s-transferase, glutathione peroxidase, glutathione, and total sulfhydryl groups. The reduced levels of nuclear factor erythroid 2-related factor-2 and the activities of heme oxygenase-1, thioredoxin, and thioredoxin reductase in NaF-alone treated rats equally compromised cellular molecular responses to oxidative stress. Also, NaF increased (p<0.05) hepatorenal inflammatory biomarkers-nitric oxide, interleukin-10, myeloperoxidase, and xanthine oxidase. Furthermore, caspase-3 and caspase-9 were increased (p<0.05) in rats treated with NaF alone. Contrastingly, BET was observed to alleviate the harmful effects of NaF. Treatment with BET mitigated NaF-induced oxido-inflammatory responses and apoptosis in the experimental rat's hepatorenal system. The study demonstrates the potential of BET to abate NaF-induced hepatorenal toxicity.

Sfrp5 overexpression reverses oxLDL-induced lipid accumulation in HVSMCs.

Atherosclerosis (AS) is the major cause of multiple cardiovascular diseases. In addition, the lipid accumulation of human vascular smooth muscle cells (HVSMCs) can cause the occurrence of AS. Sfrp5 was known to be downregulated in atherosclerosis; however, the detailed function of Sfrp5 in HVSMCs remains unclear. Specifically, we found that Sfrp5 expression in oxLDL-treated HVSMCs was downregulated. Sfrp5 overexpression inhibited the viability of HVSMCs induced by oxLDL. In addition, oxLDL-induced proliferation and migration in HVSMCs were abolished by Sfrp5 overexpression. Sfrp5 overexpression reduced oxLDL-caused oxidative stress, lipid accumulation, and inflammation in HVSMCs. Meanwhile, oxLDL treatment increased the expressions of Wnt5a, c-Myc, and β-catenin in HVSMCs, while this phenomenon was rescued by Sfrp5 overexpression. Furthermore, the inhibitory effect of Sfrp5 upregulation on the viability and migration of HVSMCs was reversed by R-spondin. These results indicate that Sfrp5 overexpression could reverse oxLDL-induced lipid accumulation in HVSMCs through inactivating Wnt5a/β-catenin signaling pathway.

Bioprotective potential of Latilactobacillus sakei and Latilactobacillus curvatus in smoked chicken legs with modified atmosphere packaging

The effects of inoculation with bioprotective bacteria (Latilactobacillus sakei and Latilactobacillus carvatus) on the bacterial succession, physicochemical properties, volatile organic compound (VOCs), and sensory attributes of smoked chicken legs stored in modified atmosphere packaging (MAP, 60% CO2 and 40% N2) at 4 °C for 28 days were investigated. Compared with the control (without inoculation), inoculation with L. sakei and L. curvatus inhibited the growth of common spoilage bacteria (Serratia proteamaculans, Weissella ceti, and Pseudomonas fragi) in smoked chicken legs stored in MAP. They significantly (P < 0.05) decreased the levels of lipid oxidation and spoilage markers such as ethanol, 1-octen-3-ol, carbon disulfide, cyclooctanol, 2,3-butanediol, and 3-methyl-1-butanol, slowed down the deterioration of the surface skin color and odor, and prolonged the shelf-life of the product. Inoculation with L. sakei and L. curvatus extended the shelf life of smoked chicken legs stored in MAP by 7 and 14 days, respectively.

Physical and microbiological quality and oxidative stability in different storage periods of Angus-Nellore heifer meat in an integrated livestock-forest system

This study aimed to evaluate the physical and microbiological quality as well as the oxidative stability of meat stored frozen (30, 60, 90, 180, and 360 days) and obtained from Angus-Nelore heifers kept in a conventional system (CS; no shade available) and Integrated Livestock-Forest (ILF-1L and ILF-3L). Forty-eight ½ Nellore ½ Angus heifers with an average initial weight of approximately 276.70 ± 20.1 kg and an average age of nine months were distributed across a randomized block design with three treatments and four replicates. After slaughter, the Longissimus thoracis muscle was collected from each carcass for pH, lipid oxidation, meat color, and microbiological analyses. The physical and microbiological quality and oxidative stability of the meat were not affected by the tree component present in the pasture. Regarding the duration of frozen storage, it was found that the pH, meat color (a*, b*, C*, H*, O/M), and lipid oxidation increased as the period of storage increased (P&lt;0.05). The physical and microbiological quality, as well as the oxidative stability of the meat, was not affected by the tree component present in the pasture. However, the meat changed as the frozen storage time increased.

Impact of urban pollution on freshwater biofilms: Oxidative stress, photosynthesis and lipid responses

Urban ecosystems are subjected to multiple anthropogenic stresses, which impact aquatic communities. Artificial light at night (ALAN) for instance can significantly alter the composition of algal communities as well as the photosynthetic cycles of autotrophic organisms, possibly leading to cellular oxidative stress. The combined effects of ALAN and chemical contamination could increase oxidative impacts in aquatic primary producers, although such combined effects remain insufficiently explored. To address this knowledge gap, a one-month experimental approach was implemented under controlled conditions to elucidate effects of ALAN and dodecylbenzyldimethylammonium chloride (DDBAC) on aquatic biofilms. DDBAC is a biocide commonly used in virucidal products, and is found in urban aquatic ecosystems. The bioaccumulation of DDBAC in biofilms exposed or not to ALAN was analyzed. The responses of taxonomic composition, photosynthetic activity, and fatty acid composition of biofilms were examined. The results indicate that ALAN negatively affects photosynthetic yield and chlorophyll production of biofilms. Additionally, exposure to DDBAC at environmental concentrations induces lipid peroxidation, with an increase of oxylipins. This experimental study provides first insights on the consequences of ALAN and DDBAC for aquatic ecosystems. It also opens avenues for the identification of new biomarkers that could be used to monitor urban pollution impacts in natural environments.

112 Nutritional, feed safety, and environmental benefits and limitations of using soybean co-products in swine diets

Abstract Various types of soybean co-products are used in swine diets which have benefits and limitations related to protein quality, environmental impact, and feed safety. To address these concerns for sustainable pork production, methodologies have evolved. Soybean processing and storage methods affecting protein oxidation have been studied less than lipid oxidation. Protein carbonyl concentrations were measured and compared among diverse samples of soybeans and soybean meal from different regions of the US and processed by mechanical or solvent extraction. Mechanically extracted soybean meal had greater concentrations of protein carbonyls than solvent extracted soybean meal which were associated with a greater concentration of residual oil. Soybeans and their co-products also contain antioxidants that may protect against more extensive lipid and protein oxidation. Understanding the interactions between natural antioxidants and oxidation of lipid and proteins in soy co-products is important for optimizing nutritional efficiency and health in sustainable pork production systems. Because soybean meal is a major component of swine diets, its origin and environmental footprint affects the environmental impact of feed, manure, and pork production. Using a spatially explicit lifecycle assessment of feed ingredients and regional manure management programs, we compared the effect of using four feeding programs on greenhouse gas (GHG) emissions, land use, and embedded water consumption in 3 major U.S. pork production regions assuming they would provide equal growth performance and carcass composition. Although environmental impacts varied among regions, the corn-soybean meal feeding program resulted in the greatest land and water use of all grower-finisher feeding programs, and more GHG emissions than feeding low protein amino acid supplemented (LP) diets and diets containing 8% supermarket food waste, but less overall GHG emissions than the distiller’s dried grains with solubles (DDGS) feeding program. Results from a subsequent study showed that feeding corn-soybean meal diets optimized growth performance and carcass composition while simultaneously reducing impacts on climate change, marine and freshwater eutrophication, and fossil resource use compared with feeding DDGS and LP diets. Lastly, the extended survival of infectious agents such as African swine fever virus in feed ingredients has important implications for biosecurity and prevention of transboundary transmission of swine diseases. We developed a risk-free in situ surrogate non-animal assay (RISNA) to estimate survival of ASFV in various feed ingredients and conditions, and results indicate greater thermal stability than previously observed, and comparable extended survival among corn- and soybean-based ingredients. These new insights will be useful in revising feed biosecurity protocols to prevent introduction and transmission of ASFV in feed supply chains. In conclusion, holistic assessments of feed ingredients, like our evaluation of soybean co-products, are needed to achieve a more sustainable, One Health approach to pork production.

134 Does inclusion of high oleic soybeans in a swine finishing ration influence lipid oxidation and consumer taste panel preference?

Abstract The objective of this study was to determine if a swine finishing ration that included soybeans with greater concentration of oleic acid will have an impact on lipid oxidation and palatability of pork. Crossbred pigs [n = 72; initial body weight (BW) = 78 ± 9 kg] were blocked by BW, sex, and distributed within 18 pens. Each pen was randomly assigned to 1 of 3 experimental diets: a control soybean-meal (CTRL), extruded conventional soybean (CONV), and extruded high oleic acid soybean (TRU). Six different harvest groups (n = 12/group) were created across treatments to ensure uniformity of final BW. Therefore, experimental diets were offered to animals for 34, 37, 41, 42, 48, or 50 d, until all pigs reached 118 ± 5 kg. Carcasses were harvested, and chilled (2°C) for 24 h, before fabricating one 2.5 cm chop from the 11th rib of the right carcass side. The chops were vacuum packaged, aged for 7 d at 2 oC, and frozen (-18 oC) for later sensory analysis. Pork chops were thawed and cooked to 71 oC peak internal temperature (AMSA sensory guidelines) and fed to 115 consumers that rated overall liking, flavor, tenderness, juiciness, and presence of off flavors using hedonic scales. Also, a 50 g sample was obtained from each loin at the 12th rib, aged for 7 d and frozen at -80 oC for evaluation of malondialdehyde (MDA) as indicator of lipid oxidation. Subcutaneous fat samples were obtained from the first thoracic vertebra, frozen, and saved for fatty acid analysis. Data were analyzed using the MIXED procedure of SAS where diet was the main effect, while pen and breed were random effects. Repeated measures were used to analyze the consumer panel. Differences were considered significant at P ≤ 0.05 with pen as experimental unit. There were no significant differences (P &amp;gt; 0.05) for consumer perception of overall like, pork flavor, and presence of off flavors. Experimental diets impacted the perception of juiciness and tenderness (P &amp;lt; 0.05), where CONV was perceived as juicier and more tender than CTRL and TRU. As expected, diet affected the fatty acid profile of subcutaneous fat (P &amp;lt; 0.0001), with TRU having the greatest percentage for oleic (43.9 %), CONV the greatest percentage for linoleic and linolenic (17.8 and 1.3 % respectively), and CTRL for saturated fatty acids (34.5 %). Surprisingly, the lipid oxidation was not affected by the diet (P &amp;gt; 0.05). These results indicate that feeding extruded high oleic soybeans during the finishing period can modify the fatty acid profile in pork by improving the percentage of unsaturated fatty acids, so these soybeans can be considered as an alternative to improve nutritional value of pork without increasing the lipid oxidation or affecting the consumers acceptability.

Hemp Flour as a Functional Ingredient for the Partial Replacement of Nitrites in a Minced Meat Model: Effect on Nutrient Composition, Antioxidant Profile and Sensory Characteristics

Consumers are becoming increasingly concerned about synthetic preservatives like nitrites in meat, prompting the meat industry to explore alternatives in order to lower nitrite levels. This study investigated the effects of incorporating hemp flour on the chemical and shelf-life characteristics of minced meat products with reduced nitrite content. Three types of products were prepared: HF0 (control) (0% hemp flour, 30 mg/kg NaNO2), HF4 (4% hemp flour, 15 mg/kg NaNO2), and HF6 (6% hemp flour, 15 mg/kg NaNO2). Analyses were conducted on proximate composition, fatty acid composition, antioxidant properties, lipid oxidation, colour, texture, and sensory characteristics. The addition of hemp flour at 6% reduced moisture content and influenced ash and sodium chloride levels in minced meat products. Despite the favorable fatty acid profile of hemp flour, its inclusion did not significantly alter the composition of the products. However, it did lead to significantly lower levels of lipid oxidation and modified the antioxidant capacity. Colour attributes were affected, with a higher hemp flour content resulting in colour deterioration. Cooking loss increased with a higher hemp flour content, and the minced meat products were significantly harder. Visual and olfactory sensory evaluation indicated that there were no significant differences in most traits, suggesting consumer acceptance of hemp-flour-enriched minced meat products. Overall, this study highlights the potential of hemp as a functional ingredient in minced meat products, also exhibiting the ability to reduce lipid oxidation.

Unraveling effective modified atmosphere conditions to improve the quality of refrigerated stored dark and white muscle fish

Although MAP in fish under refrigerated storage has been investigated since 1980, there is a knowledge gap about ideal concentration gases to improve the quality of dark- or medium/high-fat muscle fish (DM) and white- or lean/low-fat muscle fish (WM). As it is essential to industrial application, this study aimed to find promising MAP conditions to maximize fresh WM and DM quality throughout refrigerated storage based on bacteriological shelf life, physicochemical, and sensory parameters. Research articles were retrieved from Science Direct, PubMed, Web of Science, and Scopus without establishing a research period (n = 3840), and 148 were included in this systematic and meta-analytic review. Identifying an effective MAP treatment was impossible for WM, considering all physicochemical parameters evaluated in this study. However, promising MAP ranges for further optimization were found for WM (60–75% CO2/25–40% N2 and 40–80% CO2/10–30% N2/10–30% O2), which increased shelf life by 2–12 days, reduced lipid oxidation (LOX) by 1.50–3.00 mg malonaldehyde (MDA)/kg, maintained color (∆E difference < 1), and sensory quality. For DM, the best treatment was 60% CO2/40% N2 since it increased bacteriological and sensory shelf life by 10–11 days, reduced LOX by 2 mg MDA/kg and biogenic amines by 6.50–172.60 mg/kg, and retained color and hardness quality close to fresh fish. Nevertheless, studies should evaluate gas mixtures from 40 to 100% CO2 to 0–60% N2 (without O2) to optimize our findings further. Therefore, MAP is a fresh-keeping preservation alternative to meet the current trend for sustainable development of the fish production chain.

Characterization of Pseudomonas spp. contamination and in situ spoilage potential in pasteurized milk production process

To investigate the prevalence of Pseudomonas in the pasteurized milk production process and its effect on milk quality, 106 strains of Pseudomonas were isolated from the pasteurized milk production process of a milk production plant in Shaanxi Province, China. The protease, lipase and biofilm-producing capacities of the 106 Pseudomonas strains were evaluated, and the spoilage enzyme activities of their metabolites were assessed by simulating temperature incubation in the refrigerated (7 °C) and transport environment (25 °C) segments and thermal treatments of pasteurization (75 °C, 5 min) and ultra-high temperature sterilization (121 °C, 15 s). A phylogenetic tree was drawn based on 16S rDNA gene sequencing and the top 5 strains were selected as representative strains to identify their in situ spoilage potential by examining their growth potential and ability to hydrolyze proteins and lipids in milk using growth curves, pH, whiteness, Zeta-potential, lipid oxidation, SDS-PAGE and volatile flavor compounds. The results showed that half and more of the isolated Pseudomonas had spoilage enzyme production and biofilm capacity, and the spoilage enzyme activity of metabolites was affected by the culture temperature and sterilization method, but ultra-high temperature sterilization could not completely eliminate the enzyme activity. The growth of Pseudomonas lundensis and Pseudomonas qingdaonensis was less affected by temperature and time, and the hydrolytic capacity of extracellular protease and lipase secreted by Pseudomonas lurida was the strongest, which had the greatest effect on milk quality. Therefore, it is crucial to identify the key contamination links of Pseudomonas, the main bacteria responsible for milk spoilage, and the influence of environmental factors on its deterioration.

Protein and Polysaccharide Recovery from Shrimp Wastes by Natural Deep Eutectic Solvent Mediated Subcritical Water Hydrolysis for Biodegradable Film.

Environmental pollution is a significant problem due to the improper disposal of plastics and shrimp shells outdoors. Therefore, the synthesis of biodegradable film from waste materials is highly important. The novelty of this research lies in the extraction of protein hydrolysates and chitosan from shrimp shells, as well as the fabrication of biodegradable film from these materials. In this study, the composite films were produced using the solution casting method. Moreover, the combined effect of ultrasound pretreatments (UPT) and natural deep eutectic solvents (NADES) was investigated as extraction media, to determine their potential impact on shrimp waste subcritical water hydrolysis (SWH). Shrimp shells were submitted to UPT in NADES solution, followed by SWH at different temperatures ranging from 150 to 230°C under 3MPa for 20min. Then, the physiochemical properties and bioactivities of the hydrolysates were assessed to determine their suitability for use in biodegradable packaging films. Additionally, the physiochemical properties and bioactivities of the resulting hydrolysates were also analyzed. The highest amount of protein (391.96 ± 0.48mg BSA/g) was obtained at 190°C/UPT/NADES, and the average molecular size of the protein molecules was less than 1000Da with different kinds of peptide. Overall, combined UPT and SWH treatments yielded higher antioxidant activity levels than individual treatments. Finally, the application of composite films was evaluated by wrapping fish samples and assessing their lipid oxidation. The use of higher concentrations of protein hydrolysates significantly delayed changes in the samples, thereby demonstrating the film's applicability.

Acid-hydrolyzed phenolic extract of parsley (Petroselinum crispum L.) leaves inhibits lipid oxidation in soybean oil-in-water emulsions

The antioxidant activity of the natural phenolic extracts is limited in particular food systems due to the existence of phenolic compounds in glycoside form. Acid hydrolysis post-treatment could be a tool to convert the glycosidic polyphenols in the extracts to aglycones. Therefore, this research investigated the effects of an acid hydrolysis post-treatment on the composition and antioxidant activity of parsley extracts obtained by an ultrasound-assisted extraction method to delay lipid oxidation in a real food system (i.e., soybean oil-in-water emulsion). Acid hydrolysis conditions were varied to maximize total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. When extracts were exposed to 0.6 M HCl for 2 h at 80 ℃, TPC was 716.92 ± 24.43 µmol gallic acid equivalent (GAE)/L, and DPPH radical scavenging activity was 66.89 ± 1.63 %. Not only did acid hydrolysis increase the concentrations of individual polyphenols, but it also resulted in the release of new phenolics such as myricetin and gallic acid. The extract's metal chelating and ferric-reducing activity increased significantly after acid hydrolysis. In soybean oil-in-water emulsion containing a TPC of 400 µmol GAE/L, the acid-hydrolyzed extract had an 11-day lag phase for headspace hexanal compared to the 6-day lag phase of unhydrolyzed extract. The findings indicated that the conversion of glycosidic polyphenols to aglycones in phenolic extracts can help extend the shelf-life of emulsion-based foods.