Multi-scale bioimpedance flexible sensing with causal hierarchical machine learning for fish vitality evaluation under adversity stress.

It is expected that waterless low-temperature stressful environments will induce stress responses in fish and affect their vitality. In this study, we developed a laser-activated, stretchable, highly conductive liquid metal (LM) based flexible sensor system for fish multi-scale bioimpedance detection. It has excellent conformability, electrical conductivity, bending and cyclic tensile stability. Meanwhile, test result showed that wireless power supply is a potential solution for realizing safe power supply for devices inside waterless low-temperature packages. In addition, a hierarchical regression model (GC-HRM) based on Granger causality was established. The result showed that tissue bioimpedance can induce changes in individual bioimpedance with unidirectional Granger causality. The R2 of the linear regression (LR), support vector regression (SVR) and artificial neural network (ANN) models under single-scale individual bioimpedance were 0.85, 0.90 and 0.78, respectively. By adding the multi-scale bioimpedance features, the R2 of the LR, SVR and ANN models were improved to 0.95, 1.00 and 0.98, respectively.

Effect of a collagen peptide-fish oil high internal phase emulsion on the printability and gelation of 3D-printed surimi gel inks.

The effect of a high internal phase emulsion (HIPE) on three-dimensional-printed surimi gel inks was studied. Increasing the concentration of collagen peptide decreased the particle size of HIPE droplets and improved the viscoelasticity and stability. For example, when the collagen peptide concentration was 5 wt%, the viscoelasticity of the HIPE was high, as indicated by the presence of small and uniform particles, which formed a monolayer in the outer layer of the oil droplets to form stable a HIPE. A HIPE was used as the filling material to fill the surimi gel network, which reduced the porosity of the network. Surimi protein and peptides have dual emulsifying effects on the stabilization of oil. After adding the emulsion, the texture, gel properties and rheological properties of the surimi were reduced, and its printing adaptability was improved. This study provides new ideas for the production of surimi and its application in 3D printing.

Flavor formation of tilapia byproduct hydrolysates in Maillard reaction.

The Maillard reaction (MR) of tilapia byproduct protein hydrolysates was investigated for the use of byproduct protein as a food ingredient and to mask its fishy odor and bitter flavor. The flavor differences in tilapia byproduct hydrolysates before and after the MR were analyzed to explore the key flavor precursor peptides and amino acids involved in MR. The results suggested that eight key volatile substances, including 2,5-dimethylpyrazine, 2-pentylfuran, hexanal, octanal, nonanal, (E)-2-decenal, decanal, and 1-octen-3-ol contributed most to the MR products group (ROAV > 1). Ten volatile compounds, including 1-octen-3-ol, hexanal, 2-pentylfuran, 2,5-dimethylpyrazine, methyl decanoate, and 2-octylfuran, were the flavor markers that distinguished the different samples (VIP > 1). The four most consumed peptides were VAPEEHPTL, GPIGPRGPAG, KSADDIKKAF, and VWEGQNIVK. Umami peptides and bitter free amino acids (FAAs) were the key flavor precursor peptide and FAAs, respectively. Overall, the hydrolysates of tilapia byproducts with flavor improved by MR are a promising strategy for the production of flavorings.

Polysaccharide from Artocarpus heterophyllus Lam. (Jackfruit) Pulp Ameliorates Dextran Sodium Sulfate-Induced Enteritis in Rats.

A polysaccharide from Artocarpus heterophyllus Lam. (jackfruit) pulp (JFP-Ps) is known for its excellent bioactivities. However, its impact on small intestinal barrier function is still largely unexplored. The study aimed to examine the protection effect of JFP-Ps against dextran sodium sulfate-induced enteritis and its underlying mechanism. This research revealed that JFP-Ps mitigated small intestinal tissue damage by reducing the expression of pro-inflammatory cytokines and promoting the expression of the anti-inflammatory cytokine interleukin-10 in the small intestine. JFP-Ps diminished oxidative stress by bolstering the activity of antioxidant enzymes and reducing the concentration of malondialdehyde in the small intestine. In addition, JFP-Ps may restore the mechanical barrier and inhibit intestinal structure damage by augmenting the expression of short-chain fatty acids (SCFAs) receptors (GPR41/43) and up-regulating the expression of tight junction proteins (occludin). In conclusion, JFP-Ps may positively influence intestinal health by relieving oxidative stress in the small intestine, improving mechanical barrier function, activating the SCFA-GPR41/GPR43 axis, and inhibiting TLR4/MAPK pathway activation. The results augment our comprehension of the bioactivities of JFP-Ps, corroborating its great potential as a functional food.

Phycobiliprotein Peptide Extracts from Arthrospira platensis Ameliorate Nonalcoholic Fatty Liver Disease by Modulating Hepatic Lipid Profile and Strengthening Fat Mobilization.

Arthrospira platensis phycobiliprotein peptide extracts (PPEs) exhibit potential mitigative effects on hepatic steatosis. However, the precise role of PPEs in addressing high-fat-induced nonalcoholic fatty liver disease (NAFLD), as well as the underlying mechanism, remains to be elucidated. In this study, NAFLD was induced in rats through a high-fat diet (HFD), and the rats were subsequently treated with PPEs for a duration of 10 weeks. The outcomes of this investigation demonstrate that PPE supplementation leads to a reduction in body weight gain, a decrease in the accumulation of lipid droplets within the liver tissues, alterations in hepatic lipid profile, regulation of lipolysis-related gene expression within white adipose tissues and modulation of intestinal metabolites. Notably, PPE supplementation exhibits a potential to alleviate liver damage by manipulating neutral lipid metabolism and phospholipid metabolism. Additionally, PPEs appear to enhance fat mobilization by up-regulating the gene expression levels of key factors such as HSL, TGL, UCP1 and UCP2. Furthermore, PPEs impact intestinal metabolites by reducing the levels of long-chain fatty acids while concurrently increasing the levels of short-chain fatty acids. The findings from this study unveil the potential of PPE intervention in ameliorating NAFLD through the modulation of hepatic lipid profile and the reinforcement of the fat mobilization of intestinal metabolites. Thus, PPEs exhibit noteworthy therapeutic effects in the context of NAFLD.

Improving the flavor of tilapia fish head soup by adding lipid oxidation products and cysteine.

Deodorization and umami enhancement are important challenges in promoting and consuming fish products. The aim of this study was to establish whether exogenous addition of oxidized lipids and cysteine can improve the fishy, umami and create a characteristic flavor in tilapia fish head soup. The results revealed that adding oxidized lipids and cysteine enhanced the sensory attributes of fish head soup and promoted the production of pleasant-tasting amino acids and fewer bitter amino acids in the Maillard reaction. Additionally, the combination increased the levels of well-flavored aldehydes, esters, heterocyclic compounds and less hydrocarbons in the fish head soup. Among the 13 volatile compounds screened, nine were identified as characteristic aromas of fish head soup, including nonanal, (E,E)-2,4-decadienal, 1-octen-3-ol, (E)-2-decenal, acetic acid, hexanal, heptanal, 2-octenal, and decanal. Exogenous lipid oxidation products, fatty acid oxidation, and Maillard reaction can improve the aroma and umami of tilapia fish head soup.

Effects of different drying temperatures on the profile and sources of flavor in semi-dried golden pompano (Trachinotus ovatus).

Drying is an important process that can impart a different flavor to dried fish. The differences and sources of flavor of semi-dried golden pompano at different drying temperatures (40, 48, and 56 °C) were investigated, and the sensory quality, flavor substances, nonenzymatic reactions, and protein degradation were analyzed. Significant flavor differences were observed among different drying temperatures (P < 0.05), with several sensory properties showing superior results in the 40 °C group. Thirteen volatile compounds that contributed to the overall aroma were screened according to the relative odor activity value. Glu (umami taste) and Ala (sweet taste) were identified as key flavor substances based on the taste activity value. Nonanal, hexanal, heptanal, acetoin, pentadecane, and octanal represented the flavor markers. The flavor sources at higher drying temperatures included the joint action of lipid oxidation and the Maillard reaction, while those at lower temperature were lipid oxidation and protein degradation, which increased the aldehyde and free amino acid levels in the product, thus leading to the best flavor.

Identification and virtual screening of novel salty peptides from hydrolysate of tilapia by-product by batch molecular docking.

Introduction: Tilapia produces a large number of by-products during processing, which contain potentially flavorful peptides. Methods: The application of PyRx software enabled batch molecular docking andscreening of 16 potential salty peptides from 189 peptides identified in the enzymaticdigestion of tilapia by-products. Results: According to sensory analysis, all 16 peptides werepredominantly salty with a threshold of 0.256 - 0.379 mmol/L with some sournessand astringency, among which HLDDALR had the highest salty intensity, followedby VIEPLDIGDDKVR, FPGIPDHL, and DFKSPDDPSRH. I addition, moleculardocking results showed these four core peptides with high salt intensity bound to thesalt receptor TRPV1 mainly via van der Waals interactions, hydrogen bonds, andhydrophobic forces; Arg491, Tyr487, VAL441, and Asp708 were the key sites for thebinding of salty peptides to TRPV1. Therefore, the application of batch moleculardocking using PyRx is effective and economical for the virtual screening of saltypeptides.

Reconfiguration of Gut Microbiota and Reprogramming of Liver Metabolism with Phycobiliproteins Bioactive Peptides to Rehabilitate Obese Rats.

Phycobiliproteins (derived from Arthrospira platensis) bioactive peptide extracts (PPE) possess multiple pharmacological effects in the mitigation of human metabolic disorders. The role of PPE in the treatment of diet-induced obesity and the understanding of the underlying mechanism between the gut microbiome and metabolic blood circulation for obese patients remains poorly understood. In this study, we showed that PPE attenuated obesity by reducing body weight, and ameliorated glucose and lipid indexes in serum. In particular, PPE is postulated to mitigate liver steatosis and insulin resistance. On the other hand, dietary treatment with PPE was found to "reconfigure" the gut microbiota in the way that the abundances were elevated for Akkermansia_muciniphila, beneficial Lactobacillus and Romboutsia, SCFA-producing species Faecalibacterium prausnitzii, Lachnospiraceae_bacterium, Clostridiales_bacterium, probiotics Clostridium sp., Enterococcus faecium, and Lactobacillus_johnsonii, while the abundance of Firmicutes was reduced and that of Bacteroidetes was increased to reverse the imbalance of Firmicutes/Bacteroidetes ratio. Finally, the metabolomics of circulating serum using UHPLC-MS/MS illustrated that PPE supplementation indeed promoted lipid metabolism in obese rats. As summary, it was seen that PPE reprogrammed the cell metabolism to prevent the aggravation of obesity. Our findings strongly support that PPE can be regarded as a potential therapeutic dietary supplement for obesity.

Holothuria Leucospilota polysaccharides alleviate hyperlipidemia via alteration of lipid metabolism and inflammation-related gene expression.

Hyperlipemia is becoming a chronic disease that threatens human health. At the same time, people pay more and more attention to hyperlipemia. Holothuria Leucospilota polysaccharide (HLP) has been reported to ameliorate hyperlipidemia in high-fat diet-induced rats. Therefore, this study aimed to explore further metabolomics' role in improving liver function and reveal its mechanism. After oral administration of HLP for 4 weeks, total cholesterol (TC) and triglycerides (TG) levels of the liver in 100 and 200 mg/kg HLP groups were both decreased significantly (p < .05). The results showed that serum AST and ALT activity decreased by professing to be convinced of HLP. HLP also exerted antioxidant activities and up-regulated the expression of ACC, CD36, TNF-α and NF-κB in the liver of diabetic rats. Six potential biomarkers were recognized by UPLC-Q-TOF/MS and OPLS-DA. HLP alleviated liver injury by regulating the contents of metabolic end products in the serum of hyperlipidemic rats, such as nadolol and glycodeoxycholic acid. The results indicated that HLP effectively relieved HFD-induced hyperlipidemia by regulating metabolic disorders. PRACTICAL APPLICATIONS: As a chronic disease, hyperlipidemia has attracted more and more attention. Studies have shown that HLP regulates dyslipidemia, oxidative damage and inflammation to relieve hyperlipidemia. It mainly improved the liver damage caused by hyperlipidemia by inhibiting the expression of hepatic lipogenesis, oxidative stress and inflammatory factors. At the same time, we also detected six metabolites, among which high GDCA content indicated serious liver damage. Therefore, in the future, it can be suggested that HLP may be used as a functional, active substance in health products to assist in relieving hyperlipidemia, and GDCA may be used as an essential metabolic marker for the degree of liver injury.

The effects of polyphenols on fresh quality and the mechanism of partial freezing of tilapia fillets.

BACKGROUND: Fish is one of the most popular foods for consumers because of its abundant nutrition, tenderness and delicious taste. With increasing demand for tilapia fillets, practical preservation is widely used to maintain quality and safety during long-distance transportation and storage. Thus the effects of polyphenols (2 g L-1 ) on color, flavor quality and mechanism of tilapia fillets were studied during 49 days of partial freezing (-4 °C). RESULTS: Treatment with carnosic acid (CA), procyanidin (PA), quercetin (QE) and resveratrol (RSV) inhibited water migration, myoglobin oxidation and psychrophilic bacteria stability during partial freezing storage. Aeromonas and Acinetobacter were the dominant bacteria of tilapia fillets during -4 °C storage. The relative abundance of aromatic substances (T70/2) in the polyphenol groups (>20%) was richer than in the control (CON) group (17%). Partial least squares discriminant analysis results showed that the different odors of the control and polyphenol groups were completely separated. Moreover, 35 fatty acids were identified by gas chromatographic analysis. On 49 days, the ratios of unsaturated fatty acids in the PA group (58.64%), QE group (57.70%) and RSV group (57.25%) were higher than in the control group (57.19%), and the PA group was the highest. CONCLUSION: Polyphenol treatment effectively maintained freshness and improved the quality of tilapia fillets during partial freezing. The polyphenol treatment comprehensively sustained the color and flavor quality of tilapia fillets found in the proposed mechanism. In particular, PA treatment was considered a potential method for preserving the freshness of fillets. © 2022 Society of Chemical Industry.

EGCG-gelatin biofilm improved the protein degradation, flavor and micromolecule metabolites of tilapia fillets during chilled storage.

The protein degradation, flavor and micromolecule metabolites changes of (-)-epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on chilled tilapia fillets in 21 days were investigated. Morphology observations revealed EGT protected good connective myofibrillar protein. It maintained protein secondary structure by significantly increasing the proportion of α-helix (15.20%) and decreasing the ratio of random coils (22.02%) in the EGT group compared to the control (CON) group (P < 0.05). Metabolomics with UHPLC-Q-TOF/MS analysis indicated a distinct separation between the CON and treatment groups at the end of storage. Small peptides analysis demonstrated that the EGT group increased the level of sweet peptides. Additionally, the EGT group significantly reduced the formation of amino acid derivatives and esters and off-flavor development. Overall, EGT effectively improved flavor, inhibited fish protein oxidation/degradation, and verified metabolomics results. This study unveiled the potential of metabolomics to analyze metabolites determined by tilapia and monitor the changes during storage.

Sweet potato starch addition together with partial substitution of tilapia flesh effectively improved the golden pompano (Trachinotus blochii) surimi quality.

In order to improve the gel performance and edible quality of surimi for sustainable manufacture, the present study explored the feasibility of four kinds of starchs (potato, corn, sweet potato, and wheat) and fresh water fish tilapia as additives for golden pompano based surimi production. Sweet potato starch stood out as the most appropriate additive for golden pompano surimi due to the highest gel strength, lowest expressible moisture content and more compact microstructure. When the tilapia flesh substitution ratio reached 30%, best gel property of tilapia-golden pompano compound surimi with best texture property and whiteness value was achieved. Moreover, addition of 5% sweet potato starch to the golden pompano-tilapia (7:3) compound surimi comparatively obtained the optimal effect. Namely, it was observed that the texture parameters with hardness (3.62 N), gumminess (2.74 N), chewiness (17.35 mJ), cohesiveness (4.918), and springiness (0.872) being biggest values. On the other hand, the gel strength and expressible moisture content were 2,137.31 g. mm and 3.52%, respectively, which were overwhelming than other levels. Simultaneously, the whiteness of 5% addition group was 74.75, which was also a little higher than other groups. In summary, partial substitution of tilapia and proper addition of sweet potato starch effectively improved the gel performance and quality of golden pompano-based surimi products, which has potential applications in the industry of surimi.