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The effects of different concentrations (0%–20%) of soybean oil or lard added to pomfret surimi gel on its physicochemical properties and protein structure were studied. The addition of 8% lard or soybean oil significantly increased the whiteness, water-holding capacity (WHC), gel strength, storage modulus (G’) and sensory evaluation of surimi. When the addition level was higher than 8%, the strength, WHC, and G’ decreased. Surimi gel with 8% lard was better than that with the same concentration of soybean oil. The results of scanning electron microscopy (SEM) showed that lipids not only filled the void between protein molecules, but also formed an interfacial protein film on the surface, which combined with the protein matrix through protein filaments. It was shown that there was an interaction between lipids, the interfacial protein membrane and proteins in surimi gels. Raman spectra showed that the addition of lipids decreased the relative content of α-helix, and the first increases and then decreases of β-sheet. The addition of soybean oil also significantly increased the relative content of random coils, while the change in random coils of lard was not as significant as that of the soybean oil treatment group. Both soybean oil and lard led to the exposure of hydrophobic groups on the side chain of proteins in surimi gels. These results suggest that the addition of oil changes protein structure and microenvironment in surimi, which in turn affects the physicochemical properties of surimi gels. The surimi gel with 8% lard has better properties.

A novel antioxidant peptide EDEQKFWGK from porcine plasma hydrolysate (PPH) was separated by chromatography, HPLC, and identified by LC‐MS/MS. Results showed that EDEQKFWGK had better antioxidant ability (Hydroxyl RAS 32.19%, ABTS RAS 92.93% and DPPH RAS 26.76%) compared with glutathione (30.11%, 82.01%, 26.44%) due to the presence of hydrophobic, aromatic acids (F, W) and acidic amino acids (E, D), decreasing ROS by providing hydrogen atom and chelating metal ions. Furthermore, the antioxidant properties of synthetic EDEQKFWGK still significant despite in vitro digestion because of the production of smaller active peptide. Additionally, it could increase SOD, CAT, GSH‐Px to resist oxidative damage in HepG2 cells by inhibiting ROS (O2−, OH·), forming complexes to prevent OH· from destroying DNA and binding to ARE to promote antioxidase expression. Thereby, the novel peptide EDEQKFWGK from porcine plasma had much stable antioxidant properties and hade great potential in formulating functional foods. Practical applications: This research isolated a novel antioxidant peptide. Moreover, the antioxidant effects of peptide were confirmed under the in vitro digestion model and oxidative damage HepG2 cells model. The results showed the antioxidant peptide could play better effect after digestion and protect the cells from oxidative damage. These data could expand the sequence data of antioxidant peptides and promote the high‐value utilization of PPH. [ABSTRACT FROM AUTHOR]

Summary: 3D printing, as an emerging intelligent additive manufacturing processing technology, has been widely used in materials, aerospace, construction, medicine and other fields. Moreover, 3D printing technology has gradually emerged in field of food processing because of its characteristics of moulding without moulds and saving materials. The materials properties have a great influence on 3D‐printed food, especially mechanical strength and viscosity which affect accuracy and moulding ability of printed food. Moreover, the combination of materials also could change viscosity and rheology of printable materials (protein, starch, fat and hydrogel) and enhance the printing effect of not‐easy‐printable materials (cellulose). Additionally, the mixing of functional compounds and printing materials had great potential which was beneficial to personally customise functional nutritious foods to meet different people. This manuscript lays a foundation for the development and application of 3D printing technology in food processing. [ABSTRACT FROM AUTHOR]