Influence of starch-protein interactions on the digestibility and chemical properties of a 3D-printed food matrix based on salmon by-product proteins.

This study evaluated the influence of starch-protein interactions on the chemical properties and digestibility of a 3D-printed gel based on salmon by-product protein. Changes in the starch-protein interactions of the stable cornstarch (CS, 15%) and salmon protein isolate (SPI, 4%-12%) printable gels during the in vitro gastrointestinal digestion process were studied by principal component analysis. Protein-rich printed gels increased resistant starch content by 18.05%. Changes in chemical properties and the starch-protein concentration of the gels during the digestion process were highly correlated. The CS-SPI gels in the gastric and intestinal phases exhibited lower α-helix/ß-sheet ratio and fluorescence intensity values, whereas surface hydrophobicity increased. This resulted in more ordered structures with a high level of molecular interaction that inhibited enzymatic hydrolysis. This study provides crucial information about the transformations of starch-protein interactions during the digestibility of 3D-printed food matrices as an alternative source of nutrients with a high nutritional quality.

Three-Dimensional Printing Parameter Optimization for Salmon Gelatin Gels Using Artificial Neural Networks and Response Surface Methodology: Influence on Physicochemical and Digestibility Properties.

This study aimed to optimize the 3D printing parameters of salmon gelatin gels (SGG) using artificial neural networks with the genetic algorithm (ANN-GA) and response surface methodology (RSM). In addition, the influence of the optimal parameters obtained using the two different methodologies was evaluated for the physicochemical and digestibility properties of the printed SGG (PSGG). The ANN-GA had a better fit (R2 = 99.98%) with the experimental conditions of the 3D printing process than the RSM (R2 = 93.99%). The extrusion speed was the most influential parameter according to both methodologies. The optimal values of the printing parameters for the SGG were 0.70 mm for the nozzle diameter, 0.5 mm for the nozzle height, and 24 mm/s for the extrusion speed. Gel thermal properties showed that the optimal 3D printing conditions affected denaturation temperature and enthalpy, improving digestibility from 46.93% (SGG) to 51.52% (PSGG). The secondary gel structures showed that the ß-turn structure was the most resistant to enzymatic hydrolysis, while the intermolecular ß-sheet was the most labile. This study validated two optimization methodologies to achieve optimal 3D printing parameters of salmon gelatin gels, with improved physicochemical and digestibility properties for use as transporters to incorporate high value nutrients to the body.

Liposomes Loaded with Green Tea Polyphenols-Optimization, Characterization, and Release Kinetics Under Conventional Heating and Pulsed Electric Fields.

This study aimed to increase the encapsulation efficiency (EE%) of liposomes loaded with green tea polyphenols (GTP), by optimizing with response surface methodology (RSM), characterizing the obtained particles, and modeling their release under conventional heating and pulsed electric fields. GTP-loaded liposomes were prepared under conditions of Lecithin/Tween 80 (4:1, 1:1, and 1:4), cholesterol (0, 30, and 50%), and chitosan as coating (0, 0.05, and 0.1%). Particles were characterized by size, polydispersity index, ζ-potential, electrical conductivity, and optical microscopy. The release kinetics was modeled at a temperature of 60 °C and an electric field of 5.88 kV/cm. The optimal manufacturing conditions of GTP liposomes (ratio of lecithin/Tween 80 of 1:1, cholesterol 50%, and chitosan 0.1%) showed an EE% of 60.89% with a particle diameter of 513.75 nm, polydispersity index of 0.21, ζ-potential of 33.67 mV, and electrical conductivity of 0.14 mS/cm. Optical microscopy verified layering in the liposomes. The kinetic study revealed that the samples with chitosan were more stable to conventional heating, and those with higher cholesterol content were more stable to pulsed electric fields. However, in both treatments, the model with the best fit was the Peppas model. The results of the study allow us to give an indication of the knowledge of the behavior of liposomes under conditions of thermal and non-thermal treatments, helping the development of new functional ingredients based on liposomes for processed foods.

Combined Treatments of High Hydrostatic Pressure and CO2 in Coho Salmon (Oncorhynchus kisutch): Effects on Enzyme Inactivation, Physicochemical Properties, and Microbial Shelf Life.

This study focused on applying different high hydrostatic pressure + carbon dioxide (HHP + CO2) processing conditions on refrigerated (4 °C, 25 days) farmed coho salmon (Oncorhynchus kisutch) to inactivate endogenous enzymes (protease, lipase, collagenase), physicochemical properties (texture, color, lipid oxidation), and microbial shelf life. Salmon fillets were subjected to combined HHP (150 MPa/5 min) and CO2 (50%, 70%, 100%). Protease and lipase inactivation was achieved with combined HHP + CO2 treatments in which lipase activity remained low as opposed to protease activity during storage. Collagenase activity decreased approximately 90% during storage when applying HHP + CO2. Combined treatments limited the increase in spoilage indicators, such as total volatile amines and trimethylamine. The 150 MPa + 100% CO2 treatment was the most effective at maintaining hardness after 10 days of storage. Combined treatments limited HHP-induced color change and reduced the extent of changes caused by storage compared with the untreated sample. Microbial shelf life was extended by the CO2 content and not by the HHP treatments; this result was related to an increased lag phase and decreased growth rate. It can be concluded that combining HHP and CO2 could be an effective method of inactivating endogenous enzymes and extend salmon shelf life.