Influence of temperature, calcium and sucrose concentration on viscoelastic properties of prosopis chilensis seed gum and nopal mucilage dispersions

Viscoelastic properties of two nontraditional hydrocolloid dispersions were evaluated. Prosopis chilensis seed gum was evaluated based on temperature (5-80 degrees C) and added CaCl2 (0.07%), whereas nopal mucilage was evaluated based on temperature (5-80 degrees C) and sucrose concentration (0-20%). Viscoelasticity was tested by the small strain oscillatory shear test; storage modulus (G), loss modulus (G) and tan were reported. Prosopis chilensis and nopal dispersions behaved as weak gels (G'>G'') regardless of experimental condition. Raising temperature from 20 to 80 degrees C significantly increased G'. The gel structure was strengthened by adding CaCl2 and G' increased at 40 degrees C. The sucrose effect depended on concentration and temperature; at low sucrose concentrations, G' modulus increased regardless of temperature level, but at high concentrations, it decreased at temperatures >40 degrees C. In conclusion, nopal and Prosopis chilensis dispersions show weak gel structure regardless of experimental condition. G increases as temperature increases, and these dispersions could be suitable for food applications requiring heat tolerance

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 β-turn structure was the most resistant to enzymatic hydrolysis, while the intermolecular β-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

Combined Treatments of high hydrostatic pressure and CO2 in Coho Salmon (Oncorhynchus kisutch): Efects 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 degrees 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.Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) CONICYT FONDECYT 117130