Search results for "Chemical Engineering"
showing 10 items of 5892 documents
In vitro interactions between calcium, zinc, copper and iron in milk- and soy-based infant formulas / Interacciones in vitro entre calcio, cinc, cobr…
2000
Interactions among calcium, zinc, copper and iron in milk- and soy-based infant formulas were as sessed in order to evaluate the influence of supplementation with one trace element on the bioavailability of the others. The criterion used to estimate the bioavailability is the percentage of dialysis, estimated by applying an in vitro method. Infant formulas were supplemented with CaCl2, ZnO, CuCO3 Cu(OH) 22H2O and FeSO4 7H2O at two levels (maximum (+) and minimum (-) allowed by the European Union). A factorial design at two levels with three factors (Zn, Cu and Fe addition) was carried out. The main effects and the second-order interactions of the studied factors on the bioavailability of a…
The effect of abrasive pretreatment on the drying kinetics and phenolic compounds in goji berries ( Lycium barbarum L.)
2020
The paper investigated the effect of a physical surface abrasion of goji berries on drying kinetics and the evolution of phenolic compounds at 323, 333, and 343 K. A diffusion model was developed to describe the drying process. The effective diffusion coefficient estimated by the model ranged from 7.5 × 10–9 to 4.2 × 10–8 m2/s for cylinder and 2.0 × 10–9 to 1.15 × 10–8 m2/s for sphere for untreated samples (UTR). Higher values were found for treated samples (TR) (from 2.50 × 10–8 to 1.20 × 10–7 m2/s for cylinder and 8.0 × 10–9 to 2.70 × 10–8 m2/s for sphere). For the UTR samples, the values of activation energy were found to be 79.5 and 80.8 kJ/mol, respectively, in the cylinder and sphere …
Viscous Synergism in Carrageenans (κ and λ) and Locust Bean Gum Mixtures: Influence of Adding Sodium Carboxymethylcellulose
2001
Se han estudiado las interacciones sinergicas entre la goma de garrofin (LBG) y dos tipos de carragenanos (kappa y lambda). Para cada mezcla se obtuvo el indice de sinergia viscosa, Iy, en funcion de la relacion de concentraciones, z =c'LBG/c'car, y de la velocidad de cizalla. Los valores de estos indices disminuyeron al aumentar la velocidad de cizalla en ambos sistemas binarios. En las mezclas de LBG + K, I, presento un maximo para una relacion de concentraciones z = 60/40, que puede considerarse como la optima proporcion de estas gomas en la mezcla. Sin embargo, en los sistemas LBG + A, I, aumento con z en todo el intervalo considerado, es decir, la mayor sinergia correspondio a las meno…
Influence of composition on mechanical properties of strawberry gels. Compression test and texture profile analysis / Influencia de la composición de…
1999
Fruit gels were prepared containing four levels (20, 40, 60 and 80%) of strawberry pulp, four levels (0.5, 0.7, 0.9 and 1.1 %) of hydrocolloids (kappa-carrageenan plus locust bean gum, 1:1) and two levels (0, 10%) of sucrose. Their mechanical properties were analyzed by compression (failure stress and failure strain) and by texture profile analysis, TPA (hardness, cohesiveness, springiness, adhesive ness, and chewiness). Addition of hydrocolloids produced expected increases in both stress and strain at failure. Sucrose increased failure stress but did not alter strain values. Increasing the pulp content from 20 to 80% resulted in a slight increase in stress and clearly lowered strain at fa…
Influence of the addition of different origin sources of protein on meat products sensory acceptance
2019
The effect of the addition of different protein sources on the sensory properties of meat products was evaluated. Pork liver pâte, turkey patties, cooked turkey breast, fresh pork sausages, and marinated turkey breast were elaborated with soybean (control), and other protein sources, such as aspea, lentil, bean, Chlorella, Spirulina, and dairy protein. Physicochemical parameters (pH, color, and hardness), taste profile, acceptance, and preference were assessed. The incorporation of different protein sources in meat products modified the sensorial characteristics, which differentially influenced the acceptance of panelists, generating panelist groups with different preference profiles. Meat …
Cellulose ether emulsions as fat source in cocoa creams: Thermorheological properties (flow and viscoelasticity)
2019
Flow behaviour and viscoelastic properties at three different temperatures (20, 45 and 70 °C) of cocoa filling creams have been studied. These creams were composed of cocoa, starch, sugar, skimmed milk powder and non-digestible cellulose ether emulsions as fat source. Two types of methylcelluloses, MC, and two types of hydroxypropyl methylcelluloses, HPMC, with different chemical substitution degrees were employed. Results showed important differences in zero shear viscosity and shear thinning character at room temperature, due to the different internal structure revealed by the viscoelastic moduli spectra. Temperature sweeps of storage modulus showed different temperature gelation dependin…
An air-lift biofilm reactor for the production of γ-decalactones by Yarrowia lipolytica
2014
Decalactones are interesting flavouring compounds that can be produced from ricinoleic acid. In this study, the production of lactones in biofilms using Yarrowia lipolytica is investigated. The hydrophobia of cells increased for increased aeration rates resulting in higher adhesion when the reactor wall was hydrophobic (plastic). To increase adhesion, sheets of methyl-polymethacrylate (PMMA) were added in the reactor and the production of lactones increased with the surface of plastic added, reaching 850 mg/L of 3-hydroxy-γ-decalactone for 60 cm2. In an Airlift bioreactor made of PMMA, biofilms were present at the top of the reactor for increased aeration. In the meantime, a metabolic shift…
New challenges and opportunities of food fermentation processes: Application of conventional and innovative techniques.
2019
International audience
From Norway Spruce Bark to Carbon Foams : Characterization, and Applications
2020
Fresh bark from spruce Picea abies was milled and extracted with hot water. The extracts were purified in a number of steps in order to get tannin-extracts pure enough to prepare tannin-based carbon foams. The chemical composition of the extracts were analyzed. The foams were maturated and thermally treated to obtain desired properties, such as specific surface area, porosity, and compressive strength. It was possible to produce carbon foams even if they contained carbohydrate impurities. Differences in the properties of the carbon foams such as compressive strength, specific surface areas, and pore size distributions might be related to the compositions of the extracts. The foams were fina…
Note. Kinetic parameters of Bacillus stearothermophilus spores under isothermal and non-isothermal heating conditions Nota. Parámetros cinéticos del …
1998
Thermobacteriological studies using Bacillus stearotherrnophilus spores were carried out by heating the spores under isothermal and non-isothermal conditions followed by an isothermal period. Ex perimental data obtained after isothermal heating were analyzed using a two-step linear regression procedure and a one-step nonlinear regression method. Results obtained using both analytical tech niques were close, but the 90% interval of confidence for predictions was lower when the one-step nonlinear regression was used. These results indicated the convenience of using the one-step nonlin ear regression method to obtain thermal kinetic parameters for bacterial spores. Also, the parameters obtain…