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Zosteric acid (ZA) is a Zostera species-derived, sulfated phenolic acid compound with antifouling activity and has gained much attention due to its nontoxic and biodegradable characteristics. However, the yield of Zostera species available for ZA extraction is limited by natural factors, such as season, latitude, light, and temperature. Here we report the development of metabolically engineered Escherichia coli strains capable of producing ZA from glucose and glycerol. First, intracellular availability of the sulfur donor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) was enhanced by knocking out the cysH gene responsible for PAPS consumption and overexpressing the genes required for PAPS biosynthesis. Co-overexpression of the genes encoding tyrosine ammonia-lyase, sulfotransferase 1A1, ATP sulfurylase, and adenosine 5′-phosphosulfate kinase constructed ZA producing strain with enhanced PAPS supply. Second, the feedback-resistant forms of aroG and tyrA genes (encoding 3-deoxy- d -arabinoheptulosonate 7-phosphate synthase and chorismate mutase, respectively) were overexpressed to relieve the feedback regulation of L- tyrosine biosynthesis. Third, the pykA gene involved in phosphoenolpyruvate-consuming reaction, the regulator gene tyrR , the competing pathway gene pheA , and the ptsHIcrr genes essential for the PEP:carbohydrate phosphotransferase system were deleted. Moreover, all genes involved in the shikimate pathway and the talA , tktA , and tktB genes in the pentose phosphate pathway were examined for ZA production. The PTS-independent glucose uptake system, the expression vector system, and the carbon source were also optimized. As a result, the best-performing strain successfully produced 1.52 g L−1 ZA and 1.30 g L−1 p -hydroxycinnamic acid from glucose and glycerol in a 700 mL fed-batch bioreactor. • Multi-level metabolic engineering of E. coli allowed p -hydroxycinnamic acid and zosteric acid production. • Knockout of cysH and overexpression of ATPSL and APSK synergically improved intracellular PAPS content. • Accumulation of p -hydroxycinnamic acid hindered sulfation in zosteric acid biosynthesis. • Fed-batch culture produced 1.52 g L−1 zosteric acid and 1.30 g L−1 p -hydroxycinnamic acid. [ABSTRACT FROM AUTHOR]

Cheese is the potential great source of umami peptides, while studies on umami peptides in cheese are scant and current sensory-guided strategies are difficult for rapid and high-throughput screening umami peptides. Herein, the peptidomics of Cheddar cheese was conducted and 6 potential umami peptides (LEEL, EKNRLNFLK, DERF, NAVPITPTLNREQ, NMAINPSKENL, GKEKVNELSK) were screened by an integrated bioinformatics approach. Peptides except LEEL were validated as umami peptides while LEEL and DERF exhibited significant umami-enhancing effects. Molecular docking revealed that hydrogen bonds formed by hydrophilic amino acids between peptides and T1R1/T1R3 are critical for the binding of umami peptides to umami receptors. Furthermore, Phe247, Gln278 of T1R1 and Pro106 of T1R3 were inferred as key binding sites. In silico gastrointestinal digestion indicated that peptides except DERF have hypoglycemic and hypotensive potential. This work lays the foundation for high-throughput umami peptide screening and advances to understand the umami mechanism of cheese. • Peptidomics and bioinformatics were jointly used to screen umami peptides. • Six novel umami/umami-enhancing peptides were identified from Cheddar cheese. • Peptide-T1R1/T1R3 H-bonds formed by hydrophilic AAs are vital for umami perception. • Phe247, Gln278 of T1R1 and Pro106 of T1R3 were also key binding sites. • The other 5 peptides except DERF have hypoglycemic and hypotensive potential. [ABSTRACT FROM AUTHOR]

Litopenaeus vannamei is a highly sought-after seafood, but its short shelf life makes it highly perishable due to microbial and chemical reactions. Freezing is a common technology used for extending the shelf life of shrimp. However, it is essential to undergo a thawing process before consuming or further processing frozen shrimp. In this study, the effects of different thawing methods, including immersion (IT), ultrasonic (UT), microwave (MT), refrigerator (RT), and air thawing (AT) on the qualitative parameters and protein denaturation of shrimp were investigated. The results showed that UT reduced fat oxidation and color degradation and was more effective than other thawing treatments like AT, IT, MT, and RT at retaining water. Based on the results of surface hydrophobicity, turbidity, particle size, and Zeta potential, UT reduced the aggregation and oxidation of myofibrillar proteins (MP) during the thawing process compared to other thawing methods. Utilizing UT also minimized the amount of harm that was done to MP secondary and tertiary structures during the thawing process. In conclusion, UT is a novel thawing technique to maintain the quality of shrimp meat quickly and effectively compared with other thawing methods, which is important for the quality of subsequent processing of frozen shrimp. • Ultrasonic thawing (UT) significantly shortened thawing time of frozen shrimp. • UT delays changes in color and texture of texture and lipid oxidation compared to other thawing methods. • The microstructure of the UT group was smoother and more complete. • UT reduces oxidation and denaturation of myofibrillar protein (MP), which has the most stable structure. [ABSTRACT FROM AUTHOR]

This study aimed to isolate and investigate five novel xanthine oxidase (XO) inhibitory peptides FF, YF, WPW, WPDARG and YNVTGW from alkaline protease hydrolyzate (F0) of Pacific cod processing by-product bone-flesh mixture (CBFM 2 2 CBFM: Pacific cod processing by-product bone-flesh mixture.). F0 was separated by dextran gel chromatography to obtain F1, F2, F3, F4 and F5 components. The components with the highest XO inhibitory activity were analyzed and identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the peptides were further screened by molecular docking using Autodock Vina. The results showed that the F4 component had the highest XO inhibitory activity, with a molecular weight ranging from 200 to 600 Da. Five novel XO inhibitory peptides FF, YF, WPW, WPDARG and YNVTGW were obtained with IC 50 values of 0.80 mM, 0.52 mM, 1.68 mM, 0.40 mM and 0.23 mM, respectively. According to the results of molecular docking, peptides having at least one aromatic amino acid are more favorable to occupy the catalytic core of XO, reducing its catalytic activity. The amino acids Thr1010 and Phe914 in the XO active pocket interact with peptides. Overall, novel peptides from CBFM have the potential to be used as a natural uric acid reducing ingredient in functional and health foods. • Peptides were obtained by enzymatic hydrolysis of cod by-products. • Molecular docking software was used for targeted screening of active peptides. • The obtained active peptides contain at least one end of the aromatic amino acid. • Most active peptides form π-π stacking effect with xanthine oxidase 914Phe. [ABSTRACT FROM AUTHOR]

Nanoliposomes are adequate technology for the encapsulation and controlled release of bioactive compounds as well as improving their stability and bioavailability. Despite the fact that liposomes are commonly prepared from egg or soybean phospholipids, recently, more focus has been directed towards marine phospholipids (MPL) due to their health benefits and better stability. In this study, marine phospholipids nanoliposomes containing vitamin C obtained by thin-film evaporation method were prepared and characterized as well as their physicochemical stability. The mean particle size and zeta potential (ZP) of all nanoliposomes gradually increased as the phospholipids concentrations increased. The results showed a polydispersity index (PDI) value lower than 0.3 for most of samples. The encapsulation efficiency of vitamin C did not show a correlation with phospholipids concentrations. The highest encapsulation efficiency recorded was 52.09%. The antioxidant activity of nanoliposomes assessed by DPPH and reducing power assays showed an enhancement as phospholipids concentration increased. The differential scanning calorimetry (DSC) revealed a stable nanoliposomes up to 300 °C. Furthermore, the storage stability pointed to a relatively stable vitamin C in nanoliposomes when stored at 4 °C for 49 days. The present work demonstrated the potentiality of MPL nanoliposomes to protect vitamin C during long term storage. Image 1 • Vitamin C loaded marine phospholipids nanoliposomes were prepared and characterized. • Size of nanoliposomes increased as phospholipids ratios increased. • Encapsulation efficiency did not show a correlation with phospholipids ratios. • DSC analysis revealed stable nanoliposomes up to 300 °C. • Overall, the nanoliposomes showed better stability at 4 °C for 49 days. [ABSTRACT FROM AUTHOR]