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.

Influence of hot-smoking on the stability of fresh and frozen-thawed deep-skinned Atlantic mackerel fillets during cold storage.

Atlantic mackerel (Scomber scombrus) caught during the summer months in Icelandic waters after intensive feeding is rich in lipids and, thus, sensitive to lipid degradation. Recent studies have led to improved cooling and handling on board, ensuring high-quality raw material. However, studies on the development of high-quality products for human consumption are lacking. The study aimed to investigate the effects of hot-smoking on the physicochemical, microbial, and sensory quality of deep-skinned Atlantic mackerel fillets during chilled storage (1 ± 0.6°C). In addition, the quality of smoked mackerel from frozen-thawed fillets (9 months at -25 ± 1.8°C) was compared to that of fresh-smoked fillets to evaluate the possibility of the industry being able to provide smoked fillets throughout the year, despite the short fishing season. Brining and hot-smoking reduced total viable counts and inactivated Listeria monocytogenes. Hot-smoking positively affected the sensory attributes of the fillets and sensory quality was largely maintained for at least 21 days of chilled storage. Although slightly lower sensory and texture scores were obtained for frozen-thawed smoked fillets, they remained within acceptable limits throughout the period of cold storage. The shelf-life of smoked Atlantic mackerel deep-skinned fillets stored at 1°C is, therefore, assessed to be at least 21 days. Well-fed Atlantic mackerel is suitable for developing high-quality and stable smoked fillet products from both fresh and frozen-thawed raw materials.

Methods to Screen the Adhesion of Fish Cells on Plant-, Algal- and Fungal-Derived Biomaterials.

Cellular agriculture, an alternative and innovative approach to sustainable food production, has gained momentum in recent years. However, there is limited research into the production of cultivated seafood. Here, we investigated the ability of fish mackerel cells (Scomber scombrus) to adhere to plant, algal and fungal-based biomaterial scaffolds, aiming to optimize the cultivation of fish cells for use in cellular agriculture. A mackerel cell line was utilized, and metabolic assays and confocal imaging were utilized to track cell adhesion, growth, and differentiation on the different biomaterials. The mackerel cells adhered and grew on gelatin (positive control), zein, and soy proteins, as well as on alginate, chitosan, and cellulose polysaccharides. The highest adhesion and growth were on the zein and chitosan substrates, apart from the gelatin control. These findings provide a blueprint to enhance scaffold selection and design, contributing to the broader field of cellular agriculture through the development of scalable and eco-conscious solutions for meeting the growing global demand for seafood.

Preparation of Calcium-Binding Peptides Derived from Mackerel (Scomber japonicus) Protein and Structural Characterization and Stability Analysis of Its Calcium Complexes.

The purpose of this study was to prepare mackerel peptides (MPs) with calcium-binding capacity through an enzyme method and to investigate the potential role they play in improving the bioavailability of calcium in vitro. The calcium-binding capacity, degree of hydrolysis (DH), molecular weight (MW), and charge distribution changes with the enzymolysis time of MPs were measured. The structural characterization of mackerel peptide-calcium (MP-calcium) complexes was performed using spectroscopy and morphology analysis. The results showed that the maximum calcium-binding capacity of the obtained MPs was 120.95 mg/g when alcalase was used for 3 h, with a DH of 15.45%. Moreover, with an increase in hydrolysis time, the MW of the MPs decreased, and the negative charge increased. The carboxyl and amino groups in aspartic (Asp) and glutamate (Glu) of the MPs may act as calcium-binding sites, which are further assembled into compact nanoscale spherical complexes with calcium ions through intermolecular interactions. Furthermore, even under the influence of oxalic acid, MP-calcium complexes maintained a certain solubility. This study provides a basis for developing new calcium supplements and efficiently utilizing the mackerel protein resource.

Population genetic structure and demographic history of short mackerel, Rastrelliger brachysoma, in the Gulf of Thailand.

The short mackerel Rastrelliger brachysoma (Bleeker 1851) is an important fish in the Gulf of Thailand (GoT). The biology of this species has been intensively studied, but its genetic diversity is little known. The genetic diversity, population genetic structure, and demographic history of this species in the GoT were studied using complete mt control region sequences. The CR sequences of 455 mackerel samples collected from 23 localities at four fishing grounds revealed 333 haplotypes with haplotype diversity (h) per population, ranging between 0.8933 and 1.000, with an average of 0.9781. In turn, the nucleotide diversity (µ) ranged between 0.0119 ± 0.0060 and 0.0333 ± 0.0174, with an average of 0.0220 ± 0.00059.A haplotype network analysis showed that all sequences segregated into two subgroups named, clade I and clade II. Two clades were separated by 26 mutational steps. Each clade formed star-like clusters with many haplotypes derived from a common haplotype. Moreover, an analysis of molecular variance (AMOVA) revealed no significant differences among the studied localities, suggesting the presence of a single population in the GoT. Pairwise differences between samples from different fishing regions also indicated no population structure. Both Tajima's D and Fu's FS statistics were highly significant for the two clades but nonsignificant for the entire population according to a mismatch distribution analysis. These results confirmed that both clades experienced demographic expansion. The estimated expansion times for clade I and clade II were 1,542.307 years (1.5423 ka BP) and 7,602.541 (7.6025 ka BP) years, respectively.

Effect of solar powered MgO/graphene nano catalysed biodiesel production from Scomber scombrus.

The aim of the work is to find the efficiency of solar power in biodiesel preparation from mackerel fish. The paper also focusses on the ability of MgO/graphene prepared by one-pot synthesis using combustion methodology. The physicochemical properties of the material were analysed by XRD, N2 sorption studies, BET sorption analysis and SEM. The adsorption studies revealed the porosity of the graphene is intact, and the morphology studies indicated that MgO is uniformly distributed on the graphene surface. The highest biodiesel yield of 98.95% was obtained using the solar-powered Fresnel solar concentrator at 12.30 p.m in 6 min reaction time using 3 wt% MgO/GO catalyst at 65 °C. Conventional heating produced only 75% biodiesel at the same reaction condition, consuming25 min to complete. The solar assisted biodiesel had better HHV of 37.81 MJ/Kg, viscosity of 4.3 mm2/s, pour point of -15 °C, and a density of 0.875 g/mL. The optimized catalyst showed a shelf life of 5 cycles. The results portray the efficacy of natural energy source in alternative liquid fuel production.

Exploring the spatial variation of mercury in the Gulf of St. Lawrence using northern gannets as fish samplers.

Mercury (Hg) is a ubiquitous and pervasive environmental contaminant with detrimental effects on wildlife, which originates from both natural and anthropogenic sources. Its distribution within ecosystems is influenced by various biogeochemical processes, making it crucial to elucidate the factors driving this variability. To explore these factors, we employed an innovative method to use northern gannets (Morus bassanus) as biological samplers of regurgitated fish in the Gulf of St. Lawrence. We assessed fish total Hg (THg) concentrations in relation to their geographical catch location as well as to pertinent biotic and anthropogenic factors. In small fish species, trophic position, calculated from compound-specific stable nitrogen isotopes in amino acids, emerged as the most influential predictor of THg concentrations. For large fish species, THg concentrations were best explained by δ13C, indicating higher concentrations in inshore habitats. No anthropogenic factors, such as pollution, shipping traffic, or coastal development, were significantly related to THg concentrations in fish. Moreover, previously published THg data in mussels sampled nearby were positively linked with THg concentrations in gannet prey, suggesting consistent mercury distribution across trophic levels in the Gulf of St. Lawrence. Our findings point to habitat-dependent variability in THg concentrations across multiple trophic levels. Our study could have many potential uses in the future, including the identification of vulnerability hotspots for fish populations and their predators, or assessing risk factors for seabirds themselves by using biologically relevant prey.

Impact on Growth and Feed Availability from Including Jack Mackerel (Trachurus japonicas) Meal in Rockfish (Sebastes schlegeli) Feeds Which Otherwise Replace Fish Meal with Chicken By-Product Meal.

This study was conducted to elucidate the impact on the growth and feed availability of rockfish (Sebastes schlegeli) from including jack mackerel meal (JMM) in feeds which otherwise substitute 20% fish meal (FM) with chicken by-product meal (CBM). Six formulated feeds were designed to be isonitrogenous and isolipidic. Specifically, 55% FM was included in the control (Con) diet. In the Con diet, 20% FM was substituted by CBM, and then the graded levels (0, 20, 40, 60, and 80%) of JMM were included instead of FM, named as the C20J0, C20J20, C20J40, C20J60, and C20J80 diets, respectively. Five hundred and forty juvenile rockfish (initial weight of 11.2 g) were assigned to 18 tanks. All experimental feeds were fed to triplicate groups of rockfish twice daily for 8 weeks. Superior weight gain, specific growth rate (SGR), and feed intake of rockfish fed the C20J60 and C20J80 diets compared to rockfish fed the Con and C20J0 diets were observed. However, the feed utilization, biological indices, proximate composition, amino acid profiles, and blood chemistry of the rockfish were not affected by the dietary treatments. The slightly but not significantly higher economic profit index and growth performance were obtained in the C20J60 diet compared to the C20J80 diet. In conclusion, the C20J60 diet was the most recommendable treatment based on the improvement in growth performance (weight gain and SGR) and feed intake of rockfish, and the highest economic return to farmers.

Effects of different curing concentrations and drying times on the microbial community structure and metabolites of dried Spanish mackerel.

Cured Spanish mackerel has a promising market owing to its nutritious nature as well as ease of transportation and preservation. However, the nutritional and flavor formation mechanism of Spanish mackerel after curing and drying is unclear. To overcome this problem, the effects of different processing conditions on the free amino acid, microbial community, and flavor of Spanish mackerel were explored. Staphylococcus and Cobetia are the main microorganisms in cured mackerel and are closely associated with the formation of their quality. Compared with fresh mackerel, cured mackerel contains increased levels of protein, fat, and chloride, contributing to its distinctive flavor. The contents of free amino acids in the BA64 group were substantially higher than those in other groups, particularly the contents of threonine, glycine, and tyrosine. These findings will contribute to the development of high-quality cured Spanish mackerel products and cured aquatic products.

Modelling seasonal and geographical n-3 polyunsaturated fatty acid contents in marine fish from the Northeast Atlantic Ocean.

Demand for n-3 polyunsaturated fatty acids (n-3 PUFAs) exceeds supply. Large-scale studies on effects of season and geography of n-3 PUFAs in marine fish from the Northeast Atlantic Ocean (NEAO) may be used to optimize utilization and improve nutrition security. Using a sinusoid model, seasonal cycles of n-3 PUFAs were determined and found to be species-specific and clearly pronounced for the pelagic zooplankton feeding species. The Greenland halibut showed very little seasonal variation. The n-3 PUFA content in North Sea autumn-spawning (NSAS) herring peaked in summer, while Norwegian spring-spawning (NSS) herring and mackerel had their peak in autumn. A time shift of peaks in n-3 PUFAs between the two herring stocks was detected, likely due to different spawning strategies in addition to a delay of n-3 PUFAs flux in the northern regions of the NEAO. This study demonstrates that consideration of nutrient contents, such as n-3 PUFAs, when organizing and structuring fishery approaches may improve overall nutritional yield. Based on total annual Norwegian fish landings and seasonal variation in n-3 PUFA contents, n-3 PUFAs yield could theoretically be increased from 13.79 kilo ton per year from the current fishing tactics, to 15.54 if the pelagic species were only caught during the time of their seasonal n-3 PUFA peaks. Pelagic fish is a good source for dietary n-3 PUFAs, but harvest timing will also influence n-3 PUFAs intake by human consumers. One portion of fatty fish harvested during winter/spring may not meet the weekly intake reference nutritional guidelines for n-3 PUFAs. Marine n-3 PUFAs yields also varied geographically and decreased southwards, with the lowest values in Skagerrak. This study can serve as a model to understand patterns of reproductive cycles and geographical distribution of n-3 PUFAs in fatty fish from the NEAO and the novel approach may be useful to support sustainable, seasonal fishing programmes for optimization of n-3 PUFAs yields.

New Forms of Neuroactive Phospholipids for DHA Enrichment in Brain.

Low levels of docosahexaenoic acid (DHA) in the brain have been related to neurological disorders, like Alzheimer's disease (AD). After ingestion, dietary DHA must cross the blood-brain barrier, where it is absorbed as lysophosphatidylcholine (LPC), due to its role as a preferential DHA carrier in the brain. This work aimed at the production of LPC-DHA extracts to be used in supplementation/food fortification intended neural enrichment in DHA. As it is rich in DHA, especially its phospholipids (PL), Atlantic mackerel (Scomber scombrus, caught in Spring/2022) was used as a raw material. The polar lipids fraction was separated and hydrolysed with Rhizomucor miehei lipase, to enzymatically convert phosphatidylcholine (PC) into LPC. The fish (muscle and by-products) lipids fraction was used for total lipids (TL) content, lipid classes (LC) and fatty acid (FA) profile evaluation, whilst polar lipids extracts were studied for LC production and FA analysis. Muscle TL ranged between 1.45 and 4.64 g/100 g (WW), while by-products accounted for 7.56-8.96 g/100 g, with the highest contents being found in March. However, PL were more abundant in muscle (22.46-32.20% of TL). For polar lipids extracts, PL represented 50.79% of TL, among which PC corresponded to 57.76% and phosphatidylethanolamine to 42.24%. After hydrolysis, nearly half of this PC was converted into LPC. When compared to the initial PC, DHA relative content (33.6% of total FA) was significantly higher after hydrolysis: 55.6% in PC and 73.6% in LPC. Such extract, obtained from this undervalued species, may represent a promising strategy to increase DHA uptake into brain cells while allowing this species to upgrade.

Effects of Dietary Inclusion of a Crude Protein Source Exhibiting the Strongest Attractiveness to Red Sea Bream (Pagrus major) on Growth, Feed Availability, and Economic Efficiency.

Dietary incorporation of an attractive feed protein source is a practical method of enhancing feed intake and consequently improving the growth of fish. The attractiveness of 18 crude protein sources to juvenile red sea bream (Pagrus major) and the effects of the dietary inclusion of the crude protein source that exhibited the strongest attractiveness on growth, feed availability, and economic efficiency were determined. Jack mackerel meal (JMM) showed the strongest attractiveness to red sea bream among 18 crude protein ingredients. In an 8-week feeding trial, 810 juveniles were randomly distributed into 27 tanks (30 fish/tank). Nine experimental diets were prepared. The control (Con) diet included 60% fish meal (FM). Various levels (1, 3, 5, 10, 20, 40, 60, and 100%) of JMM were included at the expense of FM in the Con diet, and the resulting diets were named the JMM1, JMM3, JMM5, JMM10, JMM20, JMM40, JMM60, and JMM100 diets, respectively. Fish were hand-fed to apparent satiation twice daily for 8 weeks. The weight gain, specific growth rate, and feed consumption of red sea bream that were fed the JMM40, JMM60, and JMM100 diets were significantly (p < 0.0001 for all) higher than those of the fish fed all other diets. However, dietary JMM inclusion had no remarkable impacts on the feed utilization, biological indices, and chemical composition of the whole body of red sea bream. In terms of the economic view of the study, the economic profit index of red sea bream fed the JMM40, JMM60, and JMM100 diets was significantly (p < 0.0001) greater than that of the fish fed all other diets. In conclusion, the strongest attractiveness to red sea bream among 18 crude protein sources was observed in JMM. The inclusion of more than 40% JMM at the expense of FM in the diet of red sea bream is highly recommended for practical feed formulations to induce remarkable improvement in the growth performance of fish and the economic returns for farmers.

Determination of potentially toxic elements bioaccumulated in the commercially important pelagic fish narrow-barred Spanish mackerel (Scomberomorus commerson).

Anthropogenic activities have increased the discharge of marine contaminants threatening marine life. Small gulfs, such as the Arabian Gulf, are vulnerable to accumulating potentially toxic elements in marine species due to slow water exchange. The concentration of 21 elements was determined in the tissues of Scomberomorus commerson from Umm Al Quwain (United Arab Emirates) and Bandar Abbas (Iran). Chromium, Copper, and Iron exceeded internationally established maximum permissible limits. Sites could not be distinguished based on Principle Component Analyses of elements. Elevated Cu and Cr in muscle are of concern to marine species as well as humans. Metal Pollution Index showed a significant difference between sites, with 20.34 % and 100 % of individuals suffering high metal toxicity and poor body conditions, respectively. The Arabian Gulf is experiencing an increase in discharge of industrial wastes. Implementation of strict policies to reduce discharge of toxic substances is required to protect marine organisms and humans.

Multi-omics Analysis of Volatile Flavor Components in Pacific Chub and Spanish Mackerel during Freezing using GC-MS-O.

This study employed gas chromatography-mass spectrometry with olfactory (GC-MS-O) and multi-omics methods to investigate the changes in volatile flavor compounds during the freezing process of Pacific chub mackerel (Scomber japonicus) from Japan and China, and Spanish mackerel (Scomberomorus niphonius). A total of 18 volatile flavor compounds were identified, and significant differences in volatile flavor components were observed among samples frozen for 1 week, 1 year, and 2 years. The results of the Partial least squares regression (PLSR) indicated that the fishy odor was correlated with independent variables such as fatty acids (FA 22:4, FA 28:6, FA 24:4), differentially expressed genes (Gene.2425 (NDUFA5), Gene.38 (GPX1), and Gene.2844 (DAD1)). Classification and regression tree (CART) analysis revealed that the peak area values of fatty acids (FA 22:5, FA 20:4) and fatty acid esters of hydroxy fatty acids (FAHFA 18:0/22:3) were the main differentiating factors for fishy odor perception.

Levels of mercury, arsenic, cadmium and lead in Northeast Atlantic mackerel (Scomber scombrus) from northern European waters.

Fillets from a total of 1245 Northeast Atlantic mackerel (Scomber scombrus) sampled in different fishing areas of the Northeast Atlantic during 2007-2016 were analysed for mercury, cadmium, arsenic and lead using ICPMS. Mercury levels varied from <0.01 to 0.36 mg/kg wet weight (ww) with a total mean of 0.046 mg/kg ww and were significantly higher in Skagerrak than in the North Sea, the Norwegian Sea and west of Scotland. Cadmium concentrations varied from <0.002 to 0.16 mg/kg ww with a mean value of 0.015 mg/kg ww. Only 0.24 % and 0.16 % of the sampled fish exceeded the EU's maximum levels for cadmium and mercury, respectively. Arsenic levels varied between 0.43 and 6.9 mg/kg ww with a mean value of 2.2 mg/kg ww and showed seasonal variation following variations in fat content. Lead concentrations were low and below the analytical limit of quantification (LOQ) in 97 % of the samples.

Relatively Low Lecithin Inclusion Improved Gelling Characteristics and Oxidative Stability of Single-Washed Mackerel (Auxis thazard) Surimi.

The effect of lecithin addition on the gelling characteristics and oxidative stability of single-washed mackerel (Auxis thazard) surimi was investigated in this study. Surimi was chopped in the presence of 2.5% (w/w) NaCl with different concentrations of lecithin (0, 0.1, 0.5, 1, and 1.5 g/100 g surimi). The rheological behavior, gel-forming ability, microstructure, and lipid oxidation of lecithin-added surimi varied significantly depending on lecithin content. When compared to the control, lecithin at 0.1, 0.5, and 1 g/100 g improved the breaking force of the gel (p < 0.05). The breaking force of the gel decreased significantly as lecithin concentration increased (up to 1.5 g/100 g) (p < 0.05). Deformation, on the other hand, reacted differently to the lecithin than it did to the breaking force. At a lecithin level of 0.1 g/100 g, the surimi gel displayed improved deformation (p < 0.05). Nonetheless, at higher doses (0.5-1.5 g/100 g), lecithin considerably reduced surimi gel deformation (p < 0.05), and the gel containing lecithin at 1.5 g/100 g showed significantly decreased deformation. Surimi with 0.1 g/100 g lecithin had the lowest expressible drip (p < 0.05). In general, lecithin at concentrations ranging from 0.1 to 1 g/100 g reduced expressible drip (p < 0.05), but not at 1.5 g/100 g, which was equivalent to the control (p > 0.05). Adding lecithin to mackerel surimi improved its whiteness slightly, regardless of concentration. Lecithin impacted the microstructures of surimi gel in a concentration-dependent manner. Lecithin at a concentration of 0.1 g/100 g produced a densely packed network with small, jointed clusters and minimal holes within the gel. Joined clusters in the gel were reduced by 0.5-1.5 g/100 g lecithin, and continuous aggregates predominated. Surprisingly, at higher doses of lecithin, notably 1.5 g/100 g, porous structures with continuous voids were perceived. Surimi gels treated with various lecithin doses had lower thiobarbituric acid reactive substances (TBARS) levels than the control (p < 0.05). Overall, lecithin at a low concentration of 0.1 g/100 g was most effective at improving the texture, increasing water-holding capacity, lightening the color, and delaying lipid oxidation of single-washed mackerel surimi.

Microplastics in the stomach content of the commercial fish species Scomber colias in the Gulf of Cadiz, SW Europe.

Concerning microplastics (MPs) contamination is increasing due their negative impacts on marine food webs and their potential toxicity to wildlife and humans. In this study, we analyze the presence of MPs in the stomachs of the commercial fish species Scomber colias (Atlantic chub mackerel) in the Gulf of Cadiz (GoC). Out of the 104 analyzed stomachs, 90.4 % contained some type of MPs, with an average of 5.4 MPs per individual. Of the 1152 MPs analyzed, 91.1 % were fibers, and 8.9 % fragments type. Fourier Transformation Infrared Spectrometry analysis was performed on 152 items, revealing that 73.6 % were MPs. The most common synthetic polymers found were polyamide (64 %), polypropylene (15 %), polystyrene (12 %), polyvinyl chloride (5 %), and polyethylene (4 %). The consistent ingestion of synthetic polymers by the individuals of Atlantic chub mackerel across different zones might suggest an even distribution of MP contamination throughout the GoC.

Effects of curing concentration and drying time on flavor and microorganisms in dry salted Spanish mackerel.

This study investigated the quality changes of dry salted mackerel during curing and drying process and the relationship between flavor substances and microorganisms. The results showed that the thiobarbituric acid reactive substances (TBARS) values increased gradually with the increase of salt concentration and treatment time. The total volatile base nitrogen (TVB-N) values and total viable counts (TVC) values showed the same trend. Under 3% condition, the TVB-N values exceeded the standard and was not suitable for consumption. A total of 61 volatile flavor substances were identified by Gas chromatography-ion mobility spectrometry (GC-IMS), among which aldehydes contributed the most. Staphylococcus and Cobetia were the most abundant by High-throughput sequencing (HTS). There was significant correlation between TOP15 microorganisms and TOP20 flavor substances. Staphylococcus and Cobetia were positively correlated with 13 volatile flavor substances, which contributed to the formation of flavor in naturally fermented Spanish mackerel.

Oral intake of collagen hydrolysate from mackerel scad (Decapterus macarellus) attenuates skin photoaging by suppressing the UVB-induced expression of MMP-1 and IL-6.

OBJECTIVES: Excessive skin exposure to UVB radiation can induce photoaging caused by an imbalance in oxidative stress and inflammatory responses, damaging the skin's structure and surface layer. A previous study revealed that collagen hydrolisate extracted from the skin of mackarel scads (Decapterus macarellus) had antiaging properties that were tested in vitro, which serves as a foundation for a subsequent study of its use in vivo. This study aimed at investigating the repair effect of the mackerel scad's skin collagen hydrolysate (MSS-CH) in photoaging conditions in a mouse model. METHODS: MSS-CH was given orally in mice model of skin photoaging under chronic exposure to UVB irradiation for 12 weeks. Morphological and histological changes on the skin were evaluated using SEM and HE staining, along with the measurement of the expression of matrix metalloproteinases (MMP-1) and cytokine pro-inflammatory interleukin 6 (IL-6) using ELISA. RESULTS: MSS-CH inhibits the occurrence of epidermal thickening and damage to the dermal layer of the skin. As a result, it restores the epidermis' barrier function and reduces surface damage caused by photoaging. The skin of the MSS-CH treated group exhibited improved physical appearance with reduced fine lines, wrinkles, and enhanced smoothness. Additionally, administering MSS-CH to the mice groups reduced the expression of MMP-1 and IL-6 in UVB-exposed skin. CONCLUSIONS: Altogether, this in vivo study demonstrates the photoaging-protective properties of CH-MSS, aligning with previous in vitro data. Thus, MSS-CH emerges as a strong candidate for use as an ingredient in nutraceuticals and biocosmetics.

Formation mechanism of lipid-derived volatile flavor compounds metabolized by inoculated probiotics and their improving effect on the flavor of low-salt dry-cured mackerel.

This study aimed to evaluate the contribution and mechanisms of Lactobacillus plantarum and Zygosaccharomyces mellis inoculation to the enhancement of aroma in low-salt dry-cured mackerel (LDCM). Inoculating probiotics significantly improved the LDCM's aroma, with mixed probiotics showing a superior effect. The contents of lipid-derived volatile flavor compounds (LVFCs), free fatty acid contents, and key enzyme activities significantly increased (p < 0.05) in probiotic-treated groups. The dominant species in the probiotics-treated groups were the inoculated Lactobacillus plantarum and Zygosaccharomyces mellis, which were the main producer of metabolic enzymes for the generation of LVFCs. Lactobacillus plantarum performed well in lipid hydrolysis and aldehydes reduction, while Zygosaccharomyces mellis played a main role in aldehyde production.